Did the AR5 take the ‘dangerous’ out of AGW?

by Judith Curry

Section 12.5.5 in the WG1 Report provides some important insights on what is most commonly regarded as the ‘dangerous’ aspects of AGW.

For background on this topic, see this previous Climate Etc. post Redefining dangerous climate change.

I was pointed to section 12.5.5  by a post at BishopHill.  The relevant text is below:

12.5.5 Potentially Abrupt or Irreversible Changes

12.5.5.1 Introduction

This report adopts the definition of abrupt climate change used in Synthesis and Assessment Product 3.4 of the U.S. Climate Change Science Program CCSP (CCSP, 2008b). We define abrupt climate change as a large-scale change in the climate system that takes place over a few decades or less, persists (or is anticipated to persist) for at least a few decades, and causes substantial disruptions in human and natural systems (see Glossary). Other definitions of abrupt climate change exist. For example, in the AR4 climate change was defined as abrupt if it occurred faster than the typical time scale of the responsible forcing.

A number of components or phenomena within the Earth system have been proposed as potentially possessing critical thresholds (sometimes referred to as tipping points, (Lenton et al., 2008)), beyond which abrupt or non-linear transitions to a different state ensues. The term irreversibility is used in various ways in the literature. The AR5 report defines a perturbed state as irreversible on a given timescale if the recovery timescale from this state due to natural processes is significantly longer than the time it takes for the system to reach this perturbed state (see Glossary). In that context, most aspects of the climate change resulting from CO2 emissions are irreversible, due to the long residence time of the CO2 perturbation in the atmosphere and the resulting warming (Solomon et al., 2009). These results are discussed in Sections 12.5.2–12.5.4. Here, we also assess aspects of irreversibility in the context of abrupt change, multiple steady states and hysteresis, i.e., the question whether a change (abrupt or not) would be reversible if the forcing was reversed or removed (e.g., Boucher et al., 2012). Irreversibility of ice sheets and sea level rise are also assessed in Chapter 13.

In this section we examine the main components or phenomena within the Earth system that have been proposed in the literature as potentially being susceptible to abrupt or irreversible change (see Table 12.4).

Abrupt changes that arise from nonlinearities within the climate system are inherently difficult to assess and their timing, if any, of future occurrences is difficult to predict. Nevertheless, progress is being made exploring the potential existence of early warning signs for abrupt climate change (see e.g., Dakos et al., 2008; Scheffer et al., 2009).

Table 12.4: Components in the Earth system that have been proposed in the literature as potentially being susceptible to abrupt or irreversible change. Column 2 defines whether or not a potential change can be considered to be abrupt under the AR5 definition. Column 3 states whether or not the process is irreversible in the context of abrupt change, and also gives the typical recovery time scales. Column 4 provides an assessment, if possible, of the likelihood of occurrence of abrupt change in the 21st century for the respective components or phenomena within the Earth system, for the scenarios considered in this chapter.

(click image for full size).

The section then goes on to discuss each of these in detail (with most of the ice sheet material in ch 13).

But the bottom line is this.  The only one of these changes likely to occur in the 21st century is disappearance of the summer sea ice, and by ‘disappearance’ I assume they mean what they usually do when they say this:  < 1 M sq km left.

Bishop Hill summarizes it this way:

Abrupt changes that aren’t really abrupt and irreversible changes that aren’t really – er – irreversible.

Catastrophe? Er – we don’t know.

JC summary:  For background on this topic, see this previous Climate Etc. post Redefining dangerous climate change.  The classic reference on the topic of abrupt climate change is the NRC report Abrupt Climate Change: Inevitable Surprises.

Admittedly there are numerous definitions of ‘abrupt climate change’, but the IPCC chooses a fairly trivial one:  seemingly, the climate shift circa 2001 would qualify as an ‘abrupt’ climate change.

But the real issue is this.  The IPCC approach, using highly damped deterministic global climate models, is incapable of producing abrupt climate change (beyond the melting of Arctic sea ice, which is  not irreversible even on timescales of a decade).

The most scientifically interesting, and societally relevant topic in climate change is the possibility of abrupt climate change, with genuinely massive societal consequences (the disappearance of Arctic sea ice and regional forest diebacks arguably don’t qualify here).  The IPCC has high confidence that we don’t have to worry about  any of the genuinely dangerous scenarios (e.g. ice sheet collapse, AMOC collapse) on timescales of a century.  These collapses have happened in the past, without AGW, and they will inevitably happen sometime in the future, with or without AGW.   Are the IPCC overconfident in their conclusions on these also?

352 responses to “Did the AR5 take the ‘dangerous’ out of AGW?

  1. Yippeee! Global warming can go back to being simple benign ( as in kindly, kind, warmhearted, good-natured, friendly, warm, affectionate, agreeable, genial, congenial, cordial, approachable, tenderhearted, gentle, sympathetic, compassionate, caring, well-disposed, benevolent) global warming and not mean old catastrophic global warming!!!

  2. MangoChutney

    About time, they’ve been taken the P out of us for way too long

  3. A fan of *MORE* discourse

    Judith Curry and the IPCC inexplicably restrict their conclusions: “We don’t have to worry about any of the genuinely dangerous scenarios (e.g. ice sheet collapse, AMOC collapse) on timescales of a century”

    That’s why folks who reckon upon timescales greater than one century prefer to rely upon paleo-calibrated energy-balance models.

    That’s the difference between strong science versus mediocre science. And the difference between timorous policy versus tough-minded policy, eh Judith Curry?

    Conclusion  The best available climate-change science plainly tells us that “ We don’t  *WE DO* have to worry about the genuinely dangerous scenarios (e.g. ice sheet collapse, AMOC collapse) on timescales of [more than] a century.”

    Common-sense amendments summarized by FOMD!

    \scriptstyle\rule[2.25ex]{0.01pt}{0.01pt}\,\boldsymbol{\overset{\scriptstyle\circ\wedge\circ}{\smile}\,\heartsuit\,{\displaystyle\text{\bfseries!!!}}\,\heartsuit\,\overset{\scriptstyle\circ\wedge\circ}{\smile}}\ \rule[-0.25ex]{0.01pt}{0.01pt}

    • FOMD,

      Do man’s GHG emissions make sudden climate change more or less likely, happen sooner or later, and the consequences better or worse?

      How do you know?

      • [...] the consequences better or worse?

        Most probably worse. Any major change will invalidate many of the assumptions behind any society’s investments in process and plant. This is why marginal and/or primitive agricultural societies tend to be highly conservative.

      • No guessing and no more BS. We’ve had 20+ years of that and it’s wearing thin.

        If you reckon GHG emissions will make the consequences worse rather than better, you need to substantiate your assertion.


      • Peter Lang | October 3, 2013 at 8:59 am

        Do man’s GHG emissions make sudden climate change more or less likely, happen sooner or later, and the consequences better or worse?

        How do you know?

        Probably worse, because an environment which is forced to retain massive amounts of thermal energy doesn’t spontaneously cause things to cool. On the other hand, the other warming direction is more likely. We know this because of all our experience with positive thermal feedbacks.

        Lang, Go get your beauty sleep in and get back to me tomorrow morning, Aussie time.

      • Latimer Alder

        @Webster

        Where and what are these ‘massive amounts of thermal energy’?

        Those being discussed are said to make a difference in the deep ocean of 0.06K in about 280K. So the proportional increase in thermal energy is 0.06/280. Or about 1/40th of one percent. (0.021%), Just less than 1 part in 4000.

        Try as I might to put my terrified hat on and soil my underwear, I really cannot persuade myself that such a minor change will have the huge effects you envisage. Please explain why you do.

      • Little Lattie, They are massive in human terms. Having several extra watts per square meter of thermal power that needs to be shed is mind boggling in scope.

        Someone calculated that the current buildup of heat was the equivalent of 4 Hiroshima bombs exploding per second.

        I agree that in relative terms to the sun’s output it is outweighed, but it is still significant and worthy of being considered massive.

        Talk to the hand if you are trying to do a gotcha.

      • Latimer Alder

        @webster

        Being ‘massive in human terms’ is irrelevant. They are tiny in global terms. The ocean has a vast thermal capacity and increasing its overall temperature by 0.06C is trivial (as well as being pretty much unmeasurable).

        Sorry that you mind is boggled by these numbers. Perhaps you haven’t learnt how to do BOTE calculations for significance. I have, and my mind is unboggled.

        BTW ‘Hiroshima’s per second’ has got to be one of the daftest measures of power ever invented. Hiroshima is not remembered for its heat but its blast and radiation. The cynic might think that the inventor hoped that the association between Hiroshima and bad things would leave a residual memory. But (s)he has failed.

      • Lattie,
        I warned you that you wouldn’t catch me in a gotcha.

        The OHC is increasing at about 0.7 W/m^2 across its surface. This is enough to suppress the SST heating by half over what the land is heating at.

      • Latimer Alder

        @webster

        I wasn’t trying to catch you in a ‘gotcha’…if you can see one, you’re getting even more paranoid than before.

        Just pointing out that the vast ‘quantities of heat’ you envisage are trivial when compared to the amount already there. It’s the difference between my favourite football team getting 3897 spectators for tomorrow’s big match and 3898. Not really noticeable until after the event.

        ‘The OHC is increasing at about 0.7 W/m^2 across its surface. This is enough to suppress the SST heating by half over what the land is heating at.’

        Maybe so (though I confess I don’t fully understand what you are getting at) , but please present some observational data to explain the practical effects that this will have on us.

        Example; ‘This will make us all 15 C hotter by three weeks after Thanksgiving and our crops will die’ – or whatever today’s alarmist narrative is. ‘The oceans will be another 0.03C hotter by 2297 and the Vogons/Daleks will invade’ ain’t going to cut it.

      • WebHubTelescope says: “The OHC is increasing at about 0.7 W/m^2 across its surface. This is enough to suppress the SST heating by half over what the land is heating at.”

        Er … just to remind you, SST means ‘sea SURFACE temperature’. Like you say, it would be the surface of the ocean that received 0.7 W/m^2 more of incoming radiation, not the bulk below. So how come the SST hasn’t warmed at all since 2001 and yet the bulk has? I thought the idea was that an increase in the atmospheric radiative forcing from above would warm the skin layer a bit, reducing the temp gradient to the water layer below, thus impeding the transport of absorbed solar energy up and back out of the ocean, and thus making it pile up to increase OHC. So how come we see an increase in OHC even within a twelve and a half year period when the global skin layer hasn’t generally warmed at all (if anything, rather the opposite)?

        If the surface doesn’t warm first (from the increased radiative forcing, 0.7 W/m^2), it means the proposed mechanism through which it causes energy to slowly build in the bulk below simply isn’t observed to work. The increase in OHC has to be caused by something else. And I have a hunch of what it might be.

      • Kristian, the ocean circulation means it is not that simple. It can’t be viewed as a static pool. it is conveyor belt with cooler water coming to the surface in various areas. This cooling effect has slowed the surface warming, while the warm water sinks deeper elsewhere. Land is static and responds more immediately to the forcing above it. This is the main difference.

      • Jim D,

        The dynamics of the ocean has no bearing on the proposed atmospheric mechanism for ocean warming. That’s a different process.

        There is no documentation anywhere that the temp gradient across the surface of the global ocean has been reduced since 2001. And such a reduction is exactly what your mechanism depends upon. If we don’t see it, then your mechanism doesn’t work. Simple as that. Everything else, movement of water with different temperature up and down and back and forth is ocean dynamics and has got nothing to do with the assumed increased downward radiative flux from the atmosphere.

      • WHC: You write: “The OHC is increasing at about 0.7 W/m^2 across its surface.” Over what interval?

      • Kristian,

        Two different phenomena are, indeed, needed for the proposed explanation.

        1) Warming of the SST due to the additional CO2.
        2) Cooling from the SST due to internal variability in the upwelling and downwelling movements of ocean water.

        There’s nothing contradictory in the hypothesis that the two effects combine to maintain SST essentially unchanged. The combination allows also for slight cooling or warming of the average SST.

        That there’s nothing contradictory in that, is certainly not a proof of correctness of the hypothesis. Some people appear to tell that there’s empirical evidence for that, but the measurements are probably not accurate enough for drawing conclusions either way based on them.

      • Kristian, the dynamics has everything to do with how the warmer water gets deeper affecting the ocean heat content, and how the cooler water comes to the surface and impacts the SST. It is not just diffusion, which you assume and is leading to your confusion. The net cooling by IR is restricted by GHGs leading to a warming effect, but of course IR remains as a cooling effect itself. The ocean heat content has risen measurably and accountably from GHGs restricting the ocean IR heat loss.

      • No, Jim D. You cannot hide behind other processes. If we want to see if YOUR mechanism for ocean warming is working as proposed, then we need to look for a reducing temp gradient across the surface layer. Because THAT is the atmospheric forcing mechanism. If this signal is not observed, then there is no use postulating that it’s working.

      • Pekka,

        The point is, we know that ocean dynamics influence SSTs. It’s observed on a daily basis. We do NOT know that CO2 has a warming influence on the surface of the ocean as proposed by Peter Minnett and company. Because it’s not being observed. They propose a mechanism whereby ‘back radiation’ from the atmosphere somehow warms the cool skin which in turn reduces the temp gradient down through the surface layer. Where are the consistent global observations backing this hypothesis? The global cool skin has not warmed since 2001. How, then, do you extract the atmospheric forcing influence signal on OHC? It’s not there.

      • Kristian, the best place to look for that effect is the land. The deeper soil is warming gradually as it averages over a warming climate. The ocean is not static enough to even see such an effect. Things are washed out by motions on various scales, but the deeper ocean is warming, as measured by ARGO, and that is heat added to the earth system accounting for more than any heat change in the atmosphere or land. Heat is only added to the system by forcing, so the debate needs to be on what this forcing is.
        If you are looking for a temperature gradient changing, it is the gradient between the surface temperature and effective top-of-atmosphere radiative temperature, which is increasing from its 33 C due to the added insulating effect of CO2.

      • Kristian,

        Knowing something means different things to different people. You seem to have trust that certain measurements have been done, interpreted, and reported correctly. I wouldn’t dispute that, but I “know” with an even greater certainty that the basics of physics is understood correctly. I “know” that physics that’s true with very high certainty includes the theory of radiative heat transfer. I “know” that we can conclude from that that added CO2 produces a warming effect for the oceans.

        Being really sure that such a warming effect exists and affects ocean surface temperatures doesn’t mean that I would think that other effects are also important. I’m not surprised that the other effects turn out to be stronger over some periods.

      • @Kristian…

        The rate of heat transport from surface to mid-depth to depths is independent of the various temperatures and their gradients. Cold water is subducted at the poles, not-so-cold water is brought to the surface at temperate/sub-tropical western boundaries, and there is considerable mixing causing a net downwards flow of heat, much larger than to be expected by simple diffusion. Each of these processes can change on time scales ranging from hourly to centennially. Changes in these process lead to changes to the rate of net heat flow to the depth.

        IMO the process whose changes are most likely to be responsible for apparent changes to deep ocean heat content are changes to the nature of turbulent vertical mixing in specific areas of the world, especially the West Pacific/South China Sea, and perhaps the Caribbean and Gulf of Mexico. The former interacts with ENSO, in very complex, non-linear ways depending not so much on surface temperature but the depth of the thermocline, the specific details of tropical storm tracks and intensities, and short time-scale winds (2-24 hrs).

      • Jim D,

        I take that as a concession on your part that you have no observational backing whatsoever from the real Earth system to claim that increased atmospheric radiative forcing is what caused the rise in OHC since 2001 … even when SSTs didn’t warm at all.

        It’s a loose assertion at most. Still, you all seem to take it for granted as the eternal and established truth of the matter. And start all discussions from there. Well, it’s not. It’s a completely unsubstantiated hypothesis. No more, no less. Well, based on the observations it’s most likely wrong.

        I’m not sure why you’re even arguing about this.

      • Kristian, I started by trying to help you understand how ocean circulations make things not as simple as you thought. Then when I mention that the ocean heat content has risen, you seem to doubt that, or maybe agree to it but still don’t understand where the energy came from. To me it is clear where the energy came from, because that was predicted to happen just from basic physics, but for you it is still a mystery. I think that sums up where we stand.

      • Yes, Pekka. I know you and SoD like to promote your peculiar version of the Second Law of Thermodynamics, which you call the real 2nd Law, as opposed to an according to you imaginary 2nd Law that certain people you tend to disagree with promote. The problem is, it is your ‘real’ 2nd Law that’s the imaginary version and the one you call ‘imaginary’ is the real version.

        You say: “(…) I “know” with an even greater certainty that the basics of physics is understood correctly. I “know” that physics that’s true with very high certainty includes the theory of radiative heat transfer. I “know” that we can conclude from that that added CO2 produces a warming effect for the oceans.”

        Can you please explain me exactly how more CO2 in the atmosphere radiatively ‘produces a warming effect for the oceans’? What is the radiative mechanism here? And how does it relate to the 2nd (and 1st) Law of Thermodynamics?

        There is no underlying physics, Pekka, of radiative heat transfer anywhere explaining how a warmer object (warmed by an external heat source) gets even warmer when it in turn warms a nearby cooler object. How the cooler object becomes a contributor of ‘extra’ energy, energy already lost from the warmer object and spent at warming the cooler object, warming the warmer object beyond what its external heat source can manage.

        What is described by basic physics, is that energy to a surface/object absorbed to increase the total internal energy content of that surface/object beyond what it was before, raising its temperature … is equal to HEAT (or work). An energy flow to an object, making that object warmer than it was without that same energy flow, is HEAT (if not work). This cannot occur in nature from a cool object to a warm one.

        And yet this is exactly what you all propose.

        Compare a planet with a radiatively active atmosphere to a planet without. Let’s say the surfaces of the two planets receive and absorb the same amount of solar flux. You then claim that the surface of the former of these two planets would be a fair bit warmer than the surface of the latter. Why? It is not because of the incoming from the Sun. Those fluxes are equal. It is also not because of the initial outgoing from the surface, after absorption of and heating from that solar flux. Those fluxes would after all also be equal. There is no way to obstruct thermal radiation from escaping a warmed surface. And since the solar input is equal in both cases, then the initial terrestrial output would also be equal, relying only on surface temperature (and emissivity).

        So what is different in the two scenarios? Only the ‘extra’ incoming flux to the surface of the planet with the radiatively active atmosphere. In the ‘no atmosphere’ scenario, such an extra flux is absent. In the ‘atmosphere’ scenario, the extra flux is there. That’s the only difference. So if the surface in the latter scenario becomes warmer than the surface in the former, it’s because of this extra flux from the cool atmosphere to the warm surface alone. HEAT. And that means you’re making the atmosphere a second heat source for its own heat source, the surface.

        So, you are not increasing the incoming from the Sun to create warming. And you are not reducing the outgoing to create warming (from the piling up of solar energy). You create warming by adding ‘extra’ energy to the surface, increasing the outgoing after having warmed it some more.

        This is a clear violation of the 2nd Law (and, in fact, the 1st).

      • Sigh,

        Jim D, it’s clear you don’t even want to understand, much less address, what I’m getting at here. OHC has indeed increased since 2001. SSTs have not. That’s a big problem for your atmospheric working mechanism …

        I know exactly where we stand, Jim. You choose to believe dogma rather than what the observations from the real world are telling us. There is no trace of your hypothetical atmospheric forcing mechanism. Show us the reducing temp gradient in the global surface layer of the oceans since 2001. That’s gonna be hard as long as the skin temps haven’t warmed in that same period. If you can’t find it, it’s pretty clear we need to go elsewhere to explain the increase in OHC. Then there is no reason to assume that the atmosphere has played a role in this at all.

        Put up, or shut up. And stop deflecting and evading the issue by pointing to other processes. You take for granted that the atmosphere has a say here. Then the onus is on you to show it.

      • Kristian,

        No physicist would ever claim that a colder body acting alone could heat a warmer body. If you think that someone has proposed that, you have misunderstood the message.

        What a colder body can do is to reduce the heat loss of a warmer body and thus allow it to warm more, when heated also by some other source. In case of oceans that other source is always the sun (with a very small additional contribution from the interior of the Earth and from tides).

      • Pekka,

        “No physicist would ever claim that a colder body acting
        alone could heat a warmer body. If you think that someone has
        proposed that, you have misunderstood the message.”

        No one has ever proposed it, Pekka. Still, it is
        the exact corollary of how you propose the warming
        mechanism to work.

        This is what you say:

        “What a colder body can do is to reduce the heat loss of a
        warmer body and thus allow it to warm more, when heated also
        by some other source.”

        Did you even read my last post? You hide behind the vague
        ‘reduced heat loss’ explanation. But you need to get into
        more detail than that.

        Because in reality you’re not reducing anything. You’re not
        reducing any of the original radiative fluxes,
        either coming in or going out.

        No, you’re introducing an ‘extra’ flux coming in, separate
        from the solar flux. You’re adding a flux that wasn’t
        there before. And in so doing, create more warming.

        The added (atmospheric) flux does all the additional warming
        here. It increases the internal energy content of the
        warmer surface beyond what it was before. Nothing else. No
        restriction, no reduction.

        Hence, it is an extra heat flux.

      • AK,

        I agree.

        The ‘gradient’ thing is not my idea. It is a warmist idea. That’s how they justify atmospheric warming of the ocean. That’s the mechanism they’re clinging to.

      • Kristian,

        You write a lengthy post which includes a fundamental gross misunderstanding.

        Is this point clear?

        Do you accept that textbook level physics is a theory that has been thoroughly tested and can be considered a reliable source of information?

        If you agree on all the above two points, then we might proceed to details. If not, then I can hardly add anything worthwhile to this exchange.

      • Kristian, we have established that you agree that the ocean heat content has increased and that you don’t understand why, but meanwhile you also don’t understand or believe the greenhouse effect (which I now see from your amazing answer to Pekka). The SST has risen quite significantly, but not uniformly, and the same with the OHC. The variability is because the ocean has internal flows of energy too. No one expects these to change linearly with CO2, and it would be even more surprising if they did. However, when you take long-term trends, such as seeing what happened in the last 60 years you see the big picture without the wiggles and both the SST and OHC rose.

      • Pekka, you say:

        “You write a lengthy post which includes a fundamental gross misunderstanding.

        Is this point clear?”

        Er, no. You have to explain your claimed misunderstanding in detail, Pekka.

        “Do you accept that textbook level physics is a theory that has been thoroughly tested and can be considered a reliable source of information?”

        What textbook level physics are you talking about here? Is it the thing about a cooler object radiatively making a warmer object warmer still? Then show me empirically. Where are the ‘tests’?

        “If you agree on all the above two points, then we might proceed to details. If not, then I can hardly add anything worthwhile to this exchange.”

        Ridiculuously evasive. And quite revealing. You’re not addressing what I’m pointing at at all, Pekka. Please do. Otherwise, why should anyone take your patronising Mr. know-it-all tone seriously?

      • Kristian,

        Requiring new empirical proofs for everything that has already been proven solidly by a combination of experiments and theory does not lead anywhere. It’s only a way to prevent all learning. There’s a reason for the existence of textbooks and for university courses.

        Concepts like the Second Law must be understood before others can be accused of violating them.

        I cannot see, how we could get anywhere through exchange of further comments on the net.

      • Pekka, I can’t see you’re doing anything but evading the issue here. You’re not addressing any of the things I’m pointing at.

        Explain how it is not a violation of the laws of thermodynamics to add an ‘extra’ flux of energy to the surface to increase its internal energy content and thus raising its temperature. Like I said, you are not reducing any energy fluxes. You’re introducing an extra flux that wasn’t there before. And coming from the cooler atmosphere, this flux makes the warmer surface warmer … as if it was a transfer of heat.

      • Jim D says: “(…) we have established that you agree that the ocean heat content has increased and that you don’t understand why (…)”

        Whatever gave you that idea? I understand perfectly well why and how OHC has increased even when SSTs has cooled slightly since 2001.

        You on the other hand cannot explain it with your atmospheric mechanism, much less show it. Still, you go on assuming dogmatically that this is what caused it.

      • The gradient that is altered due to additional CO2 would never show up in the SST measurement. On a global and regional scale, nobody attempts to measure it.

      • Kristian,

        It may well be that you haven’t seen that, but your question has been presented and answered on this site really often. It’s not reasonable to repeat the same arguments in full length very often even if someone has missed them.

        Another issue is that I’m usually not willing to answer insulting comments. I believe you can figure out what I consider insulting in your earlier comments.

      • Kristian, I haven’t defended the gradient argument, that you attribute to warmists, because it is not an explanation. The explanation is the energy budget of the ocean. It loses less IR heat with more GHGs above, so it retains more energy. Restricting its loss more, warms it more because the input solar energy remains the same. You have said you have a “hunch” of how the ocean has been gaining heat content these last few decades, but have not shared it with anyone yet, as far as I can tell, so I will assume you don’t understand even your own hunch.

      • No denizens attempted to answer this question.

        Do man’s GHG emissions make sudden climate change more or less likely, happen sooner or later, and the consequences better or worse?

        How do you know?

        It seems reasonable to assume the climate science community does not have an answer to my question. I’d go further and suggest they have made little attempt to address this most important issue – that is, climate science cannot answer, and has made little attempt to provide the information that is relevant to policy analysis and to policy decision makers

      • Pekka,

        I don’t care what you find insulting. You entered this discussion without my asking. And you have brought nothing of substance to it. Your only goal seems to be to bury it.

        So if you cannot or won’t answer my questions to you, then so be it. You claimed I misunderstood. I asked you specifically how. You refuse to explain. I find that odd.

      • Jim D says: “Kristian, I haven’t defended the gradient argument, that you attribute to warmists, because it is not an explanation.”

        Good to hear. May I quote you on that?

        “The explanation is the energy budget of the ocean. It loses less IR heat with more GHGs above, so it retains more energy. Restricting its loss more, warms it more because the input solar energy remains the same.”

        Er … proof please. Observations backing this claim up. This just sounds like theoretical mumbo jumbo without real-world justification. You’re NOT restricting its loss more. You’re adding to its gain. But as soon as you add energy to a surface and raise its temperature in the process, you have created a new heat source. And the atmosphere is certainly not a heat source for the surface.

        “You have said you have a “hunch” of how the ocean has been gaining heat content these last few decades, but have not shared it with anyone yet, as far as I can tell, so I will assume you don’t understand even your own hunch.”

        It’s called ENSO.

      • lolwot,

        Minnett’s blog article expounds exactly the temp gradient mechanism I’ve been referring to here. But Jim D just admitted that he’s not defending this proposed mechanism, “because it is not an explanation”. So how is he right?

        lolwot, where’s the empirical evidence showing that this is in fact the mechanism that’s been responsible for the increase in global OHC since 2001? Has the temp gradient across the global surface skin layer grown progressively smaller over these years, causing solar energy to pile up in the bulk of the ocean? And if so, how? Seeing that global skin temperatures themselves haven’t warmed at all since then, if anything rather cooled slightly. How is this more than simply an hypothesis, and a completely unsubstantiated one at that?

    • Paleo-calibration – climate shifts from warming to cooling at the highest CO2 ‘forcings’ (and feedbacks), and from cooling to warming at the lowest. If there’s a correlation.

      • well yes. AR5 WG1 figure 5.3 appears to clearly show that sort of pattern with more abrupt rises and slower falls. They look to correlate with orbital eccentricity, though I though detailed analysis of Milkanovitch cycles suggested only partial correlation (5/9 cycles).

    • Gasp! No “tipping points!” This is in opposition to what James Hansen has claimed, you may need to pray at a new altar.

    • This post is about the next 100 years. You need to find a post where they are discussing how to read tea leaves to predict 1,000 years into the future.

    • Just look at the changes in society over the last century. : two (arguably three) world wars; Ford model T to the dawn of commercial space flight; manually operated switchboard telephone to drones bombing people from the other side of the world via the internet; steam powered weaving looms to nanotechnology and genetic engineering.

      There is more chance that the whole of society will collapse in the next 100 years than that an ice sheet will collapse. And if it doesn’t we will be living in a world that we cannot even begin to imagine today.

      Of common-sense, my friend, you possess very little.

      • Don’t forget the 10,000 thermonuclear weapons. Instant climate change at the push of a button.
        You would enjoy Kevin Kelly’s book ‘What Technology Wants’.
        I have listened to Kelly give lectures and his assessment is once human allow themselves to be physically interfaced to the internet we risk a severe disruption to civilization if something malicious should infect the net. He also thinks the explosion of self replicating nano machines pose an existential threat to both nature and mankind over the next 50 years.

      • Stephen Hawking and Scientists to Study Doomsday List

        http://guardianlv.com/2013/09/stephen-hawking-and-scientists-to-study-doomsday-list/

        “The list includes risks such as cyber attacks on world finance, utilities and transport. Manufactured bioweapons in the form of scientifically created viruses. They have even developed a scenario where computers could, similar to the plot in The Terminator, become self aware and attempt to destroy mankind.

        The world of politics focusses upon the devastation of the world by nuclear war while the brain trust will focus on, amongst other things, new technological problems that could hamper governments from dealing with disastrous events. Scientists will also look at asteroid impact, extreme and unusual climate changed weather; a highly contagious pandemic or world wide food shortages caused, again, by climate changes.”

        “Hoping for the best, prepared for the worst, and unsurprised by anything in between.”

        ― Maya Angelou, I Know Why the Caged Bird Sings

    • Matthew R Marler

      A fan of *MORE* discourse:That’s the difference between strong science versus mediocre science.

      You continue to shy away from itemizing which of the science is strong and the evidence that it is strong.

      Evidence on the absorption/emission spectra of greenhouse gases is strong. The road from there to GHG-induced climate change is full of potholes and washouts.

      Also, many climate scientists have warned about genuinely dangerous scenarios on short time scales. James Hansen, for example, has worried in print about disastrous consequences during the lives of his grandchildren, and the flooding of the periphery of Manhattan Island in no more than a half century. So the language of AR5 is a major reduction in the threat warning compared to AR4 and “An Inconvenient Truth”.

      • For Hansen, an independent line of evidence is paleoclimate, especially the Eocene, that shows the long-term effects of high CO2 levels on things like glaciers, sea-level, mammal evolution, etc.

      • Matthew R Marler

        Jim D: For Hansen, an independent line of evidence is paleoclimate, especially the Eocene, that shows the long-term effects of high CO2 levels on things like glaciers, sea-level, mammal evolution, etc.

        What does that have to do with fear for his grandchildren?

      • From all approaches paleoclimatics may be the that’s most difficult to make convincing to people who have a skeptical attitude – and that applies also to the traditional use of ‘skeptical’.

        All paleoclimatic conclusions are dependent on the narrative. Providing objective and convincing enough evidence that the large gaps of knowledge that remain on the state of the Earth at those times do not affect essentially the conclusions may remain impossible forever.

        The present increase of CO2 differs from all earlier cases, and the state of the Earth at the beginning of this ‘experiment’ is different.

        Scientist do also draw different conclusions from paleoclimatic data when quantitative results are considered. That’s natural, and I expect that to continue.

        Up to a point the climate change is understood well, but proceeding further from that has been really slow. The estimates and stated uncertainties of climate sensitivity have changed only little over decades. That’s not the full truth, but that indicates the slowness of the process.

        Developing wise climate policies must be based on something else than claims that may be true but cannot be fully substantiated. A wise climate policy is probably not an independent policy but part of a wider view of long term goals and development where climate is one main component but some others are of comparable importance.

      • Pekka, paleoclimate being independent of models is valuable as another line of evidence, and in recent years the last 60 million years has become better constrained in temperature and CO2 to allow for sensitivity ranges to be independently estimated from it, as Hansen has done. This is why Lacis just mentioned it in one of his messages today, but in the context of more recent occurrences of 450 and 400 ppm and that these levels didn’t support Arctic sea-ice last time earth had them, making this decade’s dive unsurprising in the paleoclimate context.
        Yes, skeptics haven’t started attacking paleoclimate yet, and they suffer from that, because it looks like they just ignore inconvenient results rather than discuss them, which is a pattern we see with motivated reasoning. Hopefully they will pay attention to the AR5 paleoclimate chapter, which I must read too.

      • Matthew Marler, I don’t think he mentioned his grandchildren in the paleoclimate papers, but the message is to limit total fossil fuel emissions to avoid large areas of humanly uninhabitable (i.e. dangerous) conditions in the future, so it was a longer view.

      • There are problems with paleo:

        1. For higher natural levels of CO2, the configuration of the continents and ocean basins was different, and we have no reason to suppose they have less effect than pCO2. In fact, it’s perfectly plausible that continents and ocean basins/currents were the primary drivers of temperature, which in turn drove pCO2.

        2. All the recent ice-core data has been called into question by Salby’s work, and the answers by the “concensus” were to get him blacklisted by the NSF and stranded in Europe by his Australian employer. Based on that, it’s plausible that pCO2 has been much higher than 450-500 within the last thousand years or so.

        I’m not saying either of these issues rules out a significant climate “sensitivity”, but they certainly render paleo less than certain as “proof”.

      • Pekka:”Developing wise climate policies must be based on something else than claims that may be true but cannot be fully substantiated. A wise climate policy is probably not an independent policy but part of a wider view of long term goals and development where climate is one main component but some others are of comparable importance.”

        That is a pearl, Pekka.

      • Matthew R Marler

        Pekka Pirilä Developing wise climate policies must be based on something else than claims that may be true but cannot be fully substantiated. A wise climate policy is probably not an independent policy but part of a wider view of long term goals and development where climate is one main component but some others are of comparable importance.

        I agree with that. I think the debate is about what constitutes “fully substantiated.”

      • Matthew R Marler

        Jim D: Matthew Marler, I don’t think he mentioned his grandchildren in the paleoclimate papers,

        So why did you mention them in response to my reference to Hansen’s fears about disastrous consequences during the lives of his grandchildren? Evidently those fears (concerns, worries, etc) are real, inasmuch as he wrote about them.

      • Steven Mosher

        ha.

        Watch the pee

        Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3±1°C for a 4 W m−2 CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene.

        weird, using 4watts instead of 3.7

      • Matthew Marler, I didn’t raise the issue of Hansen’s grandchildren at all, but I said I don’t think the paleo supporting evidence that he’s looked at gives him any comfort there either. You seem concerned about sea-level projections by 2100 and AR5 has larger values than AR4, so there would be more concern there too. Maybe more dangerous than AR4, if anything.

      • Strong science is physics where proof is 5-6 sigma certainty.

        Not much of climate science is strong science on that measure. (Still dying to see a proper experiment quantifying warming caused by *any* GHG free to emit any IR it might absorb.)

        Hint: if you shoot an IR laser into an IR reflective chamber, will it get warmer in there? What does that prove?

      • Matthew R Marler

        Jim D: Matthew Marler, I didn’t raise the issue of Hansen’s grandchildren at all,

        That is correct. I raised the issue of Hansen’s grandchildren as an example of a famous scientist concerned over the possibility of near-term catastrophe. What paleoclimatology had to do with the issue I raised that you responded to you never made clear.

      • Steven Mosher | October 3, 2013 at 3:28 pm |:
        “Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3±1°C for a 4 W m−2 CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene.”
        Steven, doesn’t that calculation require that you ignore the Milankovich effect on global temperature fluctuations on 10^4 years timescale (i.e. on the development of glacial maxima and interglacials) and the well-established long-term (c.10^3 years) control of atmospheric CO2 level by ocean water temperature? If you are not ignoring those two factors, how do you account for them in the calculation?

      • Matthew Marler, paleoclimate being another study area for Hansen, is why I raised it. Typically as a scientist you don’t take one line of evidence (GCMs) as proof of something unless there is an independent one. Journalists have similar rules about independent confirmation before publication. It is a good rule to have.

      • Matthew R Marler

        Jim D: Matthew Marler, paleoclimate being another study area for Hansen, is why I raised it. Typically as a scientist you don’t take one line of evidence (GCMs) as proof of something unless there is an independent one. Journalists have similar rules about independent confirmation before publication. It is a good rule to have.

        That’s a pure distraction from the fact that Hansen has raised a short-term extreme alarm with no evidence to support it. Remember the theme of the thread? The IPCC is backing off from the sort of short-term alarmism advocated by Hansen, who is repeatedly cited by fomd, whom I was responding to.

      • Matthew Marler, elsewhere I have objected that there is said to be no danger if nothing irreversible happens. Plenty of progressive reversible changes can reach dangerous levels: sea level and temperature for two, and sea level is only reversible as long as the major glaciers remain in tact. Eliminating that list does not eliminate the all dangers of climate change. The premise was wrong.

      • Matthew R Marler

        Jim D: The premise was wrong.

        The point remains unchallenged: the IPCC AR5 has backed away from the short-term alarmism advocated by James Hansen and cited repeatedly by fomd. Paleoclimate studies don’t challenge that.

      • The IPCC reports have always been conservative. They are not backing away from anything because they never said things about high sea-levels or polar methane releases being a significant factor before 2100, even the Gulf Stream shutdown. I stand to be corrected if you can find a previous report that did mention these with any more probability than they give here, but I am fairly sure they didn’t because that would have been the headline if they had. So neither did they take the “danger” out, nor modify their view of irreversible changes.

    • If you think that humans will keep on keeping on, with no regard for developing new technologies, eventually you might be right about what would happen in the long to very long run. My personal bet is that about two decades from now, solar will begin to be cheap enough to be used in countries with power grids, without subsidy. Solar will be on rooftops and in deserts, and eventually on SE, S and SW facing windows of buildings. There are huge amounts of money going into solar R&D today. I see no reason why the people who developed the technologies that are now the internet, and who kept bring the costs of semi-conductors down, year after year, for half a century, can’t and won’t do something similar for solar technologies. And when solar gets to be economic, there will begin to the an ever-larger substitution for carbon based fuels.

    • The problem of timescales more then a century is that we can barely dream of what technology will exist a century from now, never mind make a projection.

      We can reliably projected that in a century every currently existing oil well, gas well and coal mine will have been exhausted in a century. We can say that 99.999% of all the motor vehicles currently operating will be beyond repair and that 99% of all existing electric power generating capacity will also be beyond repair.

      What we will replace all of that with in the next 100 years is still unknown and unknowable.

    • Fan: If that is the “best available climate-change science”, then “climate-change science” has a century or more of difficult, disciplined and unbiased work to do. Call back when ready.

  4. “The IPCC has high confidence that we don’t have to worry about any of the genuinely dangerous scenarios (e.g. ice sheet collapse, AMOC collapse) on timescales of a century. These collapses have happened in the past, without AGW, and they will inevitably happen sometime in the future, with or without AGW.”

    I am not familiar with any past events of polar caps collapsing. Slowly diminishing over thousands of years is not what think of in terms of a collapse.
    Same goes for AMOC, though that seem more possible then polar caps
    disappearing in what could be considered a relatively short time period.
    But generally it seems that large changes in AMOC would be associated the transition periods of glacial and interglacial periods.
    Or seems this occurs when Earth has colder conditions of large ice caps on north America and/or when there is enlarged polar regions.

    • But what has happened over the last 20 years with more summer melting has been observed before and you can find scare stories in newspapers similar to todays, all quoting arctic scientists or explorers in 3-4 different periods in the last 120 years.

      • “But what has happened over the last 20 years with more summer melting has been observed before and you can find scare stories in newspapers similar to todays, all quoting arctic scientists or explorers in 3-4 different periods in the last 120 years.”

        With polar sea ice [not polar ice caps] for about 30 years we have been fairly accurately measuring it, and in arctic it has significantly decreased, 2007 and 2012 were lowest ice extent during summer. And the Antarctic
        polar sea has not decreased. This changes are not significant in terms of
        animal or human life. Though if there was generally less arctic sea ice, it sort of opens ocean shipping route during the summer and general make passage by ice breakers easier.
        Though not aware compelling evident [we only had definitive ways of exactly determine polar ice for about last 30 years- general descriptive account and other proxy type evidence neither providing a "global" monthly monitoring from satellites] it would surprise me that during our current interglacial period that there was periods when there has summers which have had far less polar sea ice than during 2007 or 2012.

        And since we have had rising sea level over last couple centuries, and this generally indicates warming global ocean volume, I expect this trend to continue for the next century [most likely] and due to warming oceans
        continuation of tread of less polar sea ice. Perhaps “ice free” or near it by 2100.
        Or I expect conditions in near future to become more like the Medieval Warm Period rather than more like the Little Ice Age.

  5. We just need Iolwot to agree that nothing much is happening and we can all go back home….

    But what will we all do with ourselves…?
    tonyb

    • tonyb
      I hope you keep writing about the cliimate. It is interesting even without C in AGW. Also, maybe it will get cold and we can study the coming ice age.
      Scott

      • Scott

        We just need the nod from Iolwot to confirm the climate wars are over .

        Its coming any time now. Perhaps we can all meet up once a year to chew over old times? Any time now…

        tonyb

  6. Admittedly there are numerous definitions of ‘abrupt climate change’, but the IPCC chooses a fairly trivial one: seemingly, the climate shift circa 2001 would qualify as an ‘abrupt’ climate change.

    And one apparently so dangerous that it ramped up the obfuscation index in the WG1 Report.

  7. The IPCC has high confidence that we don’t have to worry about any of the genuinely dangerous scenarios [...] on timescales of a century. [...] Are the IPCC overconfident in their conclusions on these also?

    Yes. In a way, it’s like the student’s introduction to calculus: two numbers both approaching zero, what happens to the ratio between them? It could go to zero, infinity, or some stable limit.

    Such catastrophic change scenarios (in the technical mathematical sense of “catastrophic”) are similar: as you define the scenario more precisely, the chance of it happening goes down, but the number of possible scenarios goes up. What matters is the area under the PDF between the limits of what generates a “catastrophic” scenario.

    IMO most anybody (including me) trying to estimate the probability of such a catastrophic scenario will focus on one particular scenario, becoming highly aware of the number of random factors that would have to come together to produce that particular scenario. As a result, there would probably be a tendency to underestimate the probability of any catastrophic scenario within the more general definition.

    I’m not trying to raise major alarms here, it seems unlikely that anthropogenic influences are any more likely to push things into a “tipping point” than natural variation. And the climate hasn’t undergone any major reorganizations since the end of the last glaciation, has it?

  8. Jim Cripwell

    I am sure people will, once again, accuse me of sounding lke a broken record. But I come back to the only issue that concerns me at this time. What do the RS and APS, and all the other learned societies, think about this issue? That is all that matters at the moment.

    • I would like to see intelligent polls of their memberships with unbiased questions that can be clearly answered. For many organizations, such as the ACS, etc. But a statement by a few officials that run the society may or may not be meaningful. It really would depend on each individual and how well read they are on the subject and their intellectual prowess. Just because someone ran for an office no one else wanted does not make them an omniscient genius.

      • I would like to see uncertainty and confidence levels explained in a way all can understand them.

      • Bill, It is not relevant WHY the learned societies write what they do. The fact is that they are who the politicians take notice of. So their opinion of the AR5 could change the minds of the people who matter.

    • “What does the RS think about this issue?”

      Go here to see what they think:

      http://www.bishop-hill.net/blog/2013/10/2/a-report-from-the-royal.html

      • From the RS meeting:
        One of the latter invocations caused an intervention from the Met Office’s Julia Slingo – she pointed out that the PDO could lead to no further warming for up to 30 years, “so we’re not out of the woods yet”. I thought that was a particularly curious turn of phrase given how so many dedicated alarmists tell me they would be overjoyed if no global warming came to pass.

        Uhuh yeah they really only want to save the planet, keeping the scare going has nothing to do with it…

      • Many thanks.

      • Wijnand, What I find interesting is that the only likely disasterous scenario, namely the disappearance of Arctic sea ice could be disproved in as little as one or two years.

    • Really?

      That is all that matters to you, here read it and tell us that you don’t agree with it.

      http://royalsociety.org/uploadedFiles/Royal_Society_Content/policy/publications/2009/4294969306.pdf

      And I quote:

      “there is no such thing as “safe” climate change”

      and

      “It is certain that GHG emissions from the burning fossil fuels and land use change lead to a warming of climate, and it is very likely that these GHGs are the dominant cause of the global warming that has taken place over the last 50 years”

      Take it or leave it, it seems that our host and the RS disagree.

      • They had a meeting about it this week and you dig up a document for m 2009. Smart, real smart.

      • Bob, That is what the RS said BEFORE the AR5 was issued.

      • Jim and Greg,
        You got anything from the Royal Society from other than Bishop Hill?

        Who doesn’t apparently understand that a trend of -0.05 to 0.15 C per decade is still a warming trend.

        I may paraphrase, despite the fact that it is still warming it’s not warming!

        They are still meeting, look who is speaking, do you expect them to change their tune from 2009?

        http://royalsociety.org/events/2013/climatescience-next-steps/

      • “there is no such thing as ‘safe’ climate change”

        OK, so is it that we haven’t had any climate change yet? Or that it was catastrophic and we missed it.

        Recent releases from the Met Office suggest they no longer want to defend the emperor’s wardrobe. They are trying to salvage what little is left of the reputation among non-warmists, in case the “pause’ they denied for so long continues.

        The 2009 statement was made at a time they were still denying the pause. So my guess is that it is “inoperative” at this time.

      • If this is any indication, they are still denying the pause, or John Shepard is, from:

        http://royalsociety.org/news/2013/Royal-Society-response-climate/

        “The recent slow-down in warming is interesting, but it may still be just a wiggle, maybe caused by a natural cycle in the ocean. If so we should expect more rapid warming in a few years time. There is no reason whatever to suppose that the slow-down is permanent: these things have happened before (e.g. 1950 to 1970), and no-one ever claimed that climate models could predict all these decadal wiggles.”

        Doesn’t seem to me like they are backing off of their 2009 statement one bit.

      • “there is no such thing as “safe” climate change”

        That’s the difference between warmists and skeptics right there. I’d venture to say every skeptic on this blog sees the profound inanity of this statement.

      • My bad, I confused the rabid Royal Society witrh the Met Office.

        I agree, the RS has joined fan and R. Gates in the CAGW bunker.

      • Nullius in verba.

    • Matthew R Marler

      JIm Cripwell: What do the RS and APS, and all the other learned societies, think about this issue?

      I agree that’s an interesting question. However, we have had in the past prominent cases of individual members of societies disputing the reports of the elected officers and selected committee members, and those disputants carry great weight in Parliament and Congress. Conditional on the reading and public debate over the IPCC report, I doubt that the opinions of the learned societies will carry any weight at all.

      At least as interesting will be the divide between the private sector scientists (and volunteer commenters) and the government-funded scientists.

      We are all broken records. Not to worry.

    • Matthew R Marler

      Jim Cripwell, allow me to elaborate. You continued with: The fact is that they are who the politicians take notice of.

      Right now the politicians are accumulating the tally of points: good science in AR5, mistakes pointed out by critics, changes noted by bloggers like Prof Curry. For example, Sen Inhof’s staff is accumulating detailed criticisms from important scientists, as they always do; that is a tiny part of the whole process.

      A few weeks from now a “learned society” will write a letter to the public or to a Senate Committee Chair saying what a swell and important report AR5 is. If they are too supportive, public esteem for the learned society will probably decline slightly, to the degree that anyone notices — especially if it is accompanied by the usual request for more government-funded research grants for the members who write the letter.

      • Ah well, then we might as well go bowling. No point in trying to find some way of driving this table home and have some influence. Cynicism shouldn’t rule out action no matter how small.

  9. George Turner

    I thought the talk of abrupt climate change and tipping points ended shortly after the release of the horrible movie “The Day After Tomorrow”, where the temperatures seemed to plummet to several hundred degrees below absolute zero.

    • There’s no real relationship between the extent of talk about them and the probability of something (within the definition) happening. Either way.

  10. An explicite admission of a lack of danger would be catastrophic to their continued wealth accumulation.

  11. There is no modern-day instrumental record for estimating the potential long-term positive feedbacks in the climate system, i.e the slow feedbacks as Hansen refers to them.

    However, the fast feedbacks are all available for analysis.
    The bottom-line for these suggest a TCR of 2C and an ECS of 3C.

    The following link shows log-sensitivity plots of TCS and ECR based on global mean surface temperature records. I applied a SOI correction to eliminate natural fluctuations.

    Again, thanks for the morning post to avoid the onslaught of Aussie crackpots.

    • Differentiate between the slow/fast systems ie what is the temporal response time of
      a) fast
      b)slow.

      • Fast responses are due to the direct GHG effect of CO2 and humidity and perhaps seasonal albedo effects, and these respond within a year.

        The slow feedback responses can take decades or centuries as cryosphere changes in the ice pack have long inertial times, as does the ocean. Hansen has further distinguished biotic and land changes in this category.

        There is no evidence that these are negative feedbacks so they contribute to the long high-side tail to the ECS PDFs.

        Note that by definition, they won’t show up in a TCR PDF.
        That’s partly why deniers like to focus on the TCR, as they only care about the future if it is within their lifetime.

      • Fast responses are due to the direct GHG effect of CO2 and humidity and perhaps seasonal albedo effects, and these respond within a year.

        The slow feedback responses can take decades or centuries as cryosphere changes in the ice pack have long inertial times, as does the ocean. Hansen has further distinguished biotic and land changes in this category.

        The failure or hesitancy to apply real numbers was identified as a flaw in Prevdi 2012.A reviewer ( Solomon) identified this here is the address and reply debate.eg

        More care needs to be taken in defining and discussing fast and slow feedbacks, and the distinctions between them

        Prevdi response

        the ‘fast’ and ‘slow’ feedback climate sensitivity are distinguished by the characteristic timescales of the feedbacks, and not by the time required for the surface temperature to reach a new equilibrium following an imposed forcing. Hansen et al. (2008) analyzed a coupled atmosphere-ocean GCM with a fast feedback climate sensitivity of 3C for doubled CO2, and found that the equilibrium
        temperature response was achieved in about a millennium. For a slow feedback climate sensitivity of 6C for doubled CO2, the equilibrium temperature response would be expected to take much longer (at least several millennia), since this response has
        been shown to be a strong function of climate sensitivity (Hansen et al., 1985).

        The problem here is that when selling the scary storyline such as the abstract they fail to address the timescales such as the effects on fast feedback’s for Hansons offspring is actually around 2^40 generations.

        http://www.earth-syst-dynam-discuss.net/2/531/2011/esdd-2-531-2011.html

        http://www.earth-syst-dynam-discuss.net/2/C341/2012/

      • Well maximo , in that case …
        We are seeing the really fast feedbacks now, and the just-fast and slow are yet to come.

        Pick your poison.

    • Leonard Weinstein

      Web,
      Those are interesting curves. Unfortunately, there is absolutely no valid basis for either. How do you explain that in the last 63 years, that only about 20 years showed temperature rising above the 1940 level, and the last 10 to 16 (or whatever period you choose) it has been flat to down? I have never seen such nonsense as you spout. You can call on aerosols or PDO or whatever, to excuse it, but you do not know what you are talking about. How many years of continued flat to dropping do you need to call quits to a flawed way of thinking? It is clear to me that human activity CO2, farming, construction, etc., has some effect, but evidence that it is significantly larger or even in the same ball game as natural variation is not there, and since we obviously are nearing the end of the Holocene, that cooling is more likely.

      • Lenny,
        Perhaps you first want to settle down. I realize that the scientific consensus is difficult to admit to once your mind is made up.

        The curves take into account natural fluctuations which tend to balance out over the long term. What you are seeing is the fast feedbacks in the log sensitivity showing up in the TCR. On land, they show up even better and that is where we can make a good estimate of the low end ECS.

        BTW, if you look at the regressive log fit, notice the intercept is at 288-25C when CO2 is 1PPM. This value 263C is close to what is predicted if the earth had no GHGs. We should be glad that we have the perfect atmospheric concentration of CO2 to support life and to thrive.

        Isn’t the GHG theory the most elegant and spot on piece of science that you have ever studied?

      • Leonard Weinstein

        Web,
        Are you calling on what is proving to be a flawed scientific consensus as proof of something? Even if a consensus happens to get it right, that is not science, but they clearly got it wrong this time, big way. So you do not accept the MWP or RWP, or even the Holocene temperature as being higher than present for much of the first half of the last 11,000 y? Where is the CO2 correlation there? What happened 1940 -1980, when the start and stop global temperatures were the same? I am an impartial scientist that actually looked at the data and came to a correct conclusion that we do not know what is going on or why, but that there is no support for your claims. It is also clear that is is as likely to cool from here as warm.

      • Leonard,
        The models are not flawed, far from it. Perhaps you are spending too much time deconstructing GCMs, which will never match any particular time series exactly.

        What you want to look at are the category of mean value and energy conservation models, of which the log sensitivity model is a member of.

        The key process step is to remove the variability of the time series instance by removing the principle components that cause that variability. These are the SOI, the volcanic data, TSI, and AMO components.

        It is about as freaking obvious as removing a 60 Hz AC signal from a DC voltage. You just do it and then move on. Forcing functions don’t care about a measly AC signal, and neither should you.

      • Leonard Weinstein

        Web,
        If you remove the principle components THAT YOU KNOW OF (obviously not including any solar effect, and probably not correct knowledge of all long period ocean effects), you still miss longer period effects such as made the ~1000 year variations causing the large variations including the MWP and LIA. Even restricting the removal to 1850-2013, and the PDO, ENSO, AMDO, and volcanoes, you have to include all available data and realistic trends, and get an approximate 0.4C to 0.5C/century rise, not 0.8C/century (from cherry picked times) as quoted or 0.2C and higher/decade as predicted. Once you find the simple fact that you started from an unusual low bottom, you have to realize the 0.4C to 0.5C/century is still not a meaningful trend.

      • Leonard,
        Half of Team Skeptic thinks the long term natural trend is cooling, because they welcome the warming. The other half of Team Skeptic thinks the long term trend is warming as a rebound from LIA.

      • Whut, the multi-millenial trend (since ~10 ka BP) is cooling. The multi-centennial trend (since LIA) is warming. The cooling trend since the Holocene peak consists of many multi-centennial warming/cooling excursions, one of them being the latest multi-centennial warming trend. Climate changes at all time-scales.

  12. Point 5 in RPJ’s post (http://rogerpielkejr.blogspot.com/2013/09/five-points-on-ipcc-report-wonky-long.html) is
    5. There is not a strong scientific basis for claiming a discernible effect of human-caused climate change on hurricanes, floods, tornadoes or drought.

    My comment to this is: What’s left for CAGW? Maybe a little AGW..if that.

  13. During the Q+A session of a recent teleconference featuring four (pro-IPCC) climate scientists and AR5 contributors:
    Linda Mearns
    Brian Soden
    Gerald Meehl
    Tad Pfeffer

    The question of “winners and losers” was asked.

    Mearns stated that the concept of winners and losers “has gone in and out of fashion”, but that the interdependency of continents/countries/cities means fewer winners.
    [Why this should be so she did not elaborate.]

    She then stated that Finland, for example, might see a longer growing season, but that this would not compensate for increased droughts and lower crop yields in equatorial regions.
    [Why she did not mention longer growing seasons not only in Finland, but across the entire higher latitudes in North America and Eurasia, which produce a substantial percentage of world grain, was again unclear.]

    She then stated that the concept of “winners and losers” is a political one – not a scientific one: “science shows fewer winners than losers”.
    [Again, Mearns did not attempt to substantiate this claim.]

    Mearns claimed that poorer developing countries, which are less able to adapt (particularly in the tropics) would be the largest losers.
    [Hmmm. I thought the "science" told us that most of the warming will occur at higher latitudes, not in the tropics.]

    She then played the fear mongering card with the statement that even rich developed nations with high adaptive capacity would be losers, as the recent floods in Colorado or Hurricane Katrina have shown.
    [No comment except: Ouch!]

    Selling the “C” in CAGW.

    Max

    • PS Here’s the link to that NCAR media teleconference with some of its IPCC lead authors, which was provided by David Wojick:

      http://www2.ucar.edu/atmosnews/news/10327/ipcc-report-teleconference-wg1-2013

      If you listen to the whole thing, you’ll see that at least three of the four scientists are doing their best to keep the fear factor alive.

      Pfeffer (contributor to the sea level chapter 13) was the least hysterical, pointing out that the AR5 increase in projected SL rise over AR4 is mostly a result of having incorporated “rapid dynamic ice loss”, a phenomenon that is not yet well understood.
      [“More work is needed” to see if “it is worse than we thought”}.

      Soden tossed in his grave concern about SL rise, since he lives in Florida. only 3 meters above SL.
      [The increase from 59 to 84 cm by 2100 doesn't seem like a real threat to him, as far as I can see.]

      Only one (Meehl) voluntarily mentioned the pause, calling it a “hiatus” during which “warming was not very large over last decade or so”.
      [Yikes! The thermometers showed cooling over the last decade not a period during which "warming was not very large".]

      More of same, I’m afraid.

      Max

      • IPCC speak: “warming was not very large” = slope less than zero

      • Tides go under Miami, streets there already flood with high tides and westerly winds.

        Time to move the whole town.

        Could be catastrophic

    • Mearns: “… , as the recent floods in Colorado or Hurricane Katrina have shown.”

      Nobel quality dumb.

    • Max I have read somewhere that there is no GHE in the tropics i.e. it is as hot as it can get because it has all those lovely oceans to produce cooling clouds and rain.

  14. There are plenty of potential consequences of AGW which do not fall into the category of “abrupt or irreversible”. Should we not be concerned about these?

    • You can be concerned if you wish. I am not convinced of any AGW, so…

    • Latimer Alder

      @andrew adams

      Name a few – and their magnitudes – and we can make a sensible assessment of the level of worry required (if any).

      General statements that ‘we need to worry’ are pretty ignorable.

      • Latimer,

        The kind of things I’m referring to are more frequent and intense heatwaves, flooding and droughts, sea level rise and its associated impacts, glacier melt, damage to sensitive ecosystems, increased tropical cyclone activity, increased hurricane strength, ocean acidification.
        Whether you (or Edim) personally want to worry about these things is up to you, my point is that there are plenty of potential effects of climate change which would not fall into the “abrupt and irreversible” category but could still cause big problems if they occur, so just because the particular outcomes the IPCC classifies as such may not happen this century it doesn’t logically mean we won’t suffer serious impacts in the shorter term.

      • Latimer Alder

        @andrew adams

        Magnitudes? ‘Increased’, ‘more intense’, ‘damage’ are all nice scary words and phrases but all unquantified. Tells us nothing.

      • Latimer,

        That’s just the old “there are uncertainties therefore we know nothing” fallacy.

      • Actually, that is the “there are uncertainties, so we need to study it more” truism. It is not the “the science is settled” fallacy.

      • Anyway, I wasn’t attempting a literature review, it was a rough outoine of the kind of things which are anticipated. If you want more information look at the IPCC report or the underlying research.

      • Latimer Alder

        @andrew adams

        No fallacy at all mon brave.

        Just pointing out that the SIZE of an effect as well as its direction has a big part to play in determining what our response should be. And if you can’t even estimate the order of magnitude, then you really don’t know very much about it at all. Certainly not enough to design ‘solutions’.

      • But we might consider that given that we don’t know the size of the effect but we do know that it will have negative impacts then it’s best to try to avoid it altogether. Uncertainty is not our friend in this situation.

    • Like what Andrew.

      consequences based on model projections don’t count.

      • timg56,

        See my above reply to Latimer. Some of the things I mention may be based to some extent on model projections, if you want to disregard them on that basis it’s up to you but the rest of us are under no obligation to.

      • k scott denison

        Andrew, can you point to one (1) event since 1900 that is tied to the warming we’ve seen? Take your pick of heat wave, drought, hurricane, sea level rise, etc. just one event that indicates there is an added risk to climate change (which, by the way, happens all the time).

      • Latimer Alder

        @andrew adams

        You’re welcome to scare yourself stupid about anything you want to as far as I’m concerned (though its a bit sad that you feel the need to do so on such flimsy grounds).

        But if you want he rest of us to join you in doing something expensive, inconvenient, ineffectual and counter-productive about it, you’ll need far more robust arguments than ‘there’s an unvalidated model that an activist programmer has used to illustrate that your bad habits will lead to some sort of bad sh*t sometime a long way in the future’

        Those happy halcyon carefree days of 2007 and ‘Trust Me, I’m a Climatologist’ are long past.

      • Latimer,

        Well I’m not a climatologist, that’s not my argument and I’m not scared stupid.

        I’m fully aware that some people are perfectly content to dismiss out of hand the argument that climate change is a threat and there is a need to take action. That’s fine, there are plenty of others who already accept that argument, including many of those who are actually in power, and there are many others who are unconvinced but open to persuasion. It doesn’t need everyone to agree.

      • What about the people that do not dismiss it out of hand, but studied the science and rejected the premiss?

        It seems most of the people here are in that category, yet you either are unaware of them or chose to ignore them.

      • k scott denison,

        As I’m sure you’re aware attributing specific events directly to AGW is very difficult, but here’s what the IPCC says about the general trends for certain kinds of events.

        Anthropogenic influences have contributed to observed increases in atmospheric moisture content in the atmosphere (medium confidence), to global-scale changes in precipitation patterns over land (medium confidence), to intensification of heavy precipitation over land regions where data are sufficient (medium confidence), and to changes in surface and subsurface ocean salinity (very likely).

        It is now very likely that human influence has contributed to observed global scale changes in the frequency and intensity of daily temperature extremes since the mid-20th century, and likely that human influence has more than doubled the probability of occurrence of heat waves in some locations.

        In any case my argument is about what is projected to happen over the rest of this century, not what has happened so far.

      • philjourdan, OK, there are some that fall into that category, but their minds seem to be made up, I don’t see any prospect of them being persuaded otherwise. To be fair I doubt they could persuade me to change my mind either.

      • And therein lies your problem. The fact that you do not understand their position, and the fact that your “mind is made up” (kind of like the types you listed – but you are one of them).

        The ones I am talking about have examined all the evidence, weighed it, and applied the scientific methods to it. They are looking for more data and information. Yet as soon as they ask a question, some 300 pound monkey comes in and slaps them down with ad hominems and grand statements of the “science being settled”. So naturally they stop asking the stupid gorillas and keep questioning. But to the true believers in the religion, that is still heresy.

        They are not trying to change your mind. They are seeking knowledge. And when that becomes a taboo endeavor (as the team has made it), that is when science suffers.

      • The distinction is between the curious and the faithful.
        ================

  15. I am continually amazed by the CAGWists’ failure to even consider the zero’th order question: is humanity better off if we stop using fossil fuels? Arguably, the answer is a resounding “NO!” Whether or not AGW is real, bad things will continue to happen in various parts of the world. Is humanity better off with more or fewer resources? If we were somehow able to severely curtail/stop the use of fossil fuels, the developing world would be less able to respond to and recover from the inevitable disasters that will befall them. Isn’t it immoral for those in the developed world to unilaterally decide that that should be their fate?

    My point is that if you believe that CO2 is the cause of global warming, [er, climate change] AND you believe that the best course for humanity is to raise the overall standard of living (education, health, income) of anyone left behind then capping CO2 is probably not the best policy. It would deny both the developing and developed world the resources necessary to raise the standard of living of those who have been left behind. Much better for the developed world to use its energy more efficiently while allowing the developing world to, well, develop.

    If we plot a variety of phenomena (expected life span, literacy, energy use…) vs national GDP, they follow an S-curve (those interested can see this in the links embedded in http://www.resilientus.org/the-death-of-growth-or-how-i-learned-to-stop-worrying-and-love-the-s-curve/). To me, this implies that the best way to first stabilize, and then to reduce our reliance on fossil fuels, is to get everyone onto the plateau of the S-curve, and then gradually beome more efficient. To those who don’t believe CO2 is a problem, it’s still a good idea – more efficient use of energy means less reliance on the Middle East, less push to mine coal…

    • +1 well said
      Innovation comes from market forces …or else we would all still be driving Model T’s

  16. Tell this to CBS News which only publishes reliable non-partisan news;

    http://mrc.org/articles/networks-embrace-catastrophic-warnings-latest-ipcc-report

    Next come climate “damages” for poor distressed Oyster farmers from Kalifornia.

  17. Hank Zentgraf

    Judith, what is the residence time of CO2 emissions.

    • Hank Zentgraf

      Judith may give you a more scientific estimate, but I have seen nothing more specific from IPCC other than the statement made back in the TAR:

      Table 1 of the IPCC TAR WG1 report says that the CO2 lifetime in the atmosphere before being removed is somewhere between 5 and 200 years with the footnote: “No single lifetime can be defined for CO2 because of the different rates of uptake by different removal processes.”

      Seems like a pretty wide range (and it isn’t really substantiated anywhere, either).

      Narrowing this down a bit, the long-term residence time of CO2 in our climate system has been estimated to equal a half-life of around 100-120 years. (Data presented at the Yale Forum by Zeke Hausfather).

      http://www.yaleclimatemediaforum.org/2010/12/common-climate-misconceptions-atmospheric-carbon-dioxide/

      Max

    • Hank

      You asked about the “residence time of CO2 emissions”

      Half of the human emissions “disappear” right away, since on average the atmospheric concentration increase is about half the human emission; so the “residence time” of this fraction is 0.

      The fraction “remaining” in the atmosphere bounces around on a year-by-year basis, but is around half of the total. This fraction has decreased by around 1% per decade since CO2 measurements started at Mauna Loa, and is around 5%-age points lower today than it was back then.

      I have seen no explanation for this observed trend.

      Max

      • Never seen it plotted that way before but my instant reaction would be the further from thermodynamic equilibrium we are, the fast the system will act to correct it.

        This is what we would expect from any negative feedback, linear or non-linear, and the usual physical laws would lead us to expect that.

        Interesting plot , there may be something more to be dug out of that, thanks.

      • PS. notable dip for Mt Agung and Mt. P
        Cooler surface absorbs more CO2 excess: temp dependency of Henry’s “constant”.

        Drop in US emissions during 1973 petrol crisis also seems evident.

      • Greg,

        Looking at changes in one year does not really tell much about the residence time. What’s removed in one year is by far mainly due to cumulative emissions of earlier years.

        It’s true that details of carbon cycle are not known accurately. A lot of uncertainty remains in particular on the long tail. The removal is not exponential, but can be approximated by a sum of several exponentials over the first 200 years or so.

        AR4 has a 28 page chapter 7.3 on the carbon cycle.

        AR 5 discusses the carbon cycle in chapter 6 spending even more pages on the subject. AR5 gives tens (or more) of references to related studies. An one page summary is presented in Box 6.1: Multiple Residence Times for an Excess of CO2 Emitted in the Atmosphere Figure 1 of that Box tells about the conclusions. From that we can see, that the uncertainties are, indeed, large, but that a non-negligible fraction is believed to persist thousands of years.

      • Hank
        The residence time is a few years. The adjustment time is what really matters and that is indefinite.

        This time is deduced by solving the diffusion equation, and since the solution to the diffusion equation has fat tails with respect to time, there isn’t one characteristic adjustment time. The reason that it doesn’t exist is that the mean as calculated by an integral of the time profile diverges.

        But for the sake of discussion, this number is on the order of centuries.

      • BTW, the curve that Mad Max Manacker presented was explained badly by someone who has no clue about the kinetics of diffusion. By badly, I mean totally wrong — moreover, the slight decline is well understood by the solution to the diffusion equation under changing stimulus. mad Max likes to keep the FUD flowing.

      • Pekka, The “sum of exponentials” is a trick to model the kernel function solution to the diffusion equation. Much easier to do this rather than tell someone to use an error function to reproduce the long tails.

      • Webby

        Sorry, it appears that you are confused once again.

        The curve I posted simply shows the fraction of the CO2 emitted by humans, which actually remains in the atmosphere year-by-year (CDIAC and Mauna Loa data).

        This bounces all over the place on a year-by-year basis (from 15% to 90%) but averages around half.

        And the linear trend of this fraction has decreased by around 1 %-age point per decade.

        The average was 55.0% over the period 1959-1990 and 50.6% over the period 1990-2010.

        No fancy theoretical diffusion calculations necessary, Webby.

        As Sgt. Friday used to say, “Just the facts, ma’am.”

        Max

      • It is not random. The uptake is less efficient in warmer years which doesn’t bode well for the future as the oceans warm more.

      • “Jim D | October 3, 2013 at 6:39 pm |

        It is not random. The uptake is less efficient in warmer years which doesn’t bode well for the future as the oceans warm more.”

        Well if you use your statement as way to measure, and you know human emission has increased, then it indicates global cooling over last decade or so.
        Large cooling.
        So your measurement stick is inaccurate, or we not in a pause but in severe cooling trend [which doesn't fit other ways of measuring global average temperature].

      • Jim D

        You are right.

        It is “not random”.

        And warmer oceans (even if they are only marginally warmer) should absorb less CO2, and there is a fairly good year-to-year correlation between the fraction remaining in the atmosphere and the temperature change from the previous year (higher in warmer years).

        But that does not change the observed fact that the fraction remaining in the atmosphere has decreased (by around 1%-point per decade since Mauna Loa measurements started – from around 55% to around 50% (even though the ocean temperature increased marginally over this period).

        If you don’t believe it, check the published data (Mauna Loa and CDIAC).

        Max

    • The sink is undefined and certainly dynamic. Like ocean heat it’s a devils playground of essential AGW mythology about co2 residence time. It’s only through elaborate “compounding” of human co2 concentrations that you can get to astounding numbers of what allegedly are the total human co2 fingerprint. All the variables are largely unknown but it’s more useful to the agenda to guess with confidence than talk about the fact that humans emit less than 5% of co2 compared to nature (we actually have a good estimate on that). They need residence time compounding and the idiotic assumption that the sink is a constant being “taxed by humans” for the meme to reach escape velocity.

      For what ever the reason residence time is usually neglected in the blood feud. It’s basic religious doctrine in the warming circle although there is no physical evidence or research to back their claims of human co2 is being retained more than a few weeks let alone the 100+ year claims. You will soon end up in a “prove god does or doesn’t exist” debate with a warming advocate and they call it “settled science”. It’s a hard claim to falsify because of the unknowns so skeptics often skip it. Then I again I adhere to the standard that the burden is on the one making the claim but that’s all before “post normal” science took over. Climate science is post normal and the residence of co2 claim is a perfect example of why it must be that way.

      Bottom line, no evidence of long co2 residence time or the warming claims of 40% long-term co2 retention, it’s unknown. I expect someone to flip out on my post. This is like drawing a picture of Mohammed, mocking Joseph Smith scroll translations or dropping a cross in urine in warming circles. It’s a basic core belief of the AGW religion and even pointing out it’s scientifically inconclusive is blasphemy.

      We certainly know more about contributions than we know about the sink. You would think that would have ended the hyperbolic co2 claims decades ago but obviously it didn’t.

      • cwon14, stick to your little political rants because you have no clue about the difficulty in permanently sequestering a non-condensing material like CO2.

      • Webby

        Tell it to all the plants out there.

        They love to “sequester” CO2 (it’s their life’s blood).

        Could it be that the more of it that’s around, the faster they gobble it up?

        Just a thought for you to gnaw on, Webby.

        Max

      • wht……non-condensing material like CO2?
        How do you make dry ice?

      • > How do you make dry ice?

        Add gin.

      • They mean non-condensing at the temperatures normally experienced naturally on earth, not like water which does condense.

        You make dry ice by collecting CO2, pressurizing and cooled until it’s liquid and then the pressure is reduced forming solid CO2.

        Glad to be of help answering your rhetorical question.

  18. Roger Pielke, Sr. gave a slide presentation in Tennessee on October 1, 2013,

    Extreme Weather in the Coming Decades – What is the Role of Climate Change?

    http://pielkeclimatesci.files.wordpress.com/2013/09/ppt-128.pdf

    • Don B

      Interesting presentation. It’s always good to hear a voice of reason in the doomsday din.

      Thanks for posting the link.

      Max

  19. Everything listed is irreversible unless a way is found to reduce CO2 in the atmosphere, and there is no way to do that. Also it doesn’t have to be abrupt to be dangerous. 4 C over century is bad enough, and is only “abrupt” when considering paleoclimate scales where this kind of change occurred over many millennia after the last ice age. So I wouldn’t dismiss “dangerous” quite so easily, and certainly the IPCC didn’t.

    • Jim D

      You say you wouldn’t dismiss “dangerous” quite so easily, and certainly the IPCC didn’t

      Would you dismiss:

      – non-dangerous?

      or even:

      – potentially beneficial?

      If so, why (specifically)?

      Max

      • Only dangerous for some fraction of humanity. How about that? I was questioning the premise in the title.

      • Jim D

        Thanks for response.

        dangerous for some fraction of humanity

        If you add “potentially”, it might make more sense.

        How about “potentially beneficial for some fraction of humanity”?

        Max

      • manacker, no I am pretty sure it is dangerous to some, and relative to that who cares about the beneficiaries when you put it in perspective.

      • JimD

        Can you clarify who it is dangerous to?

        tonyb

      • tonyb, I could point you to the World Bank report on the impacts of a 4 C change. Probably easy to Google. You can take your pick from a slew of things in there.

      • Jim D

        You ask “who cares about the beneficiaries?”

        Umm…the beneficiaries?

        Max

    • Everything listed is irreversible unless a way is found to reduce CO2 in the atmosphere, and there is no way to do that.

      Is this a statement of religious belief?

      • I don’t understand the question. Are you suggesting things are reversible even if CO2 keeps rising? I thought I made a statement of the obvious, but I guess not obvious for some.

      • I don’t understand the question. Are you suggesting things are reversible even if CO2 keeps rising?

        Denial in action. I was suggesting that there is a large variety of perfectly achievable ways to reduce atmospheric pCO2. You don’t seem to have even seen this as a possibility in my question.

      • “Everything listed is irreversible unless a way is found to reduce CO2 in the atmosphere”

        this also _assumes_ that CO2 is THE cause of just about everything on the shopping list.

        That is clearly not the case ” but I guess not obvious for some.”

      • AK, to me a reduction of CO2 levels is much less likely than a significant reduction in the emission rate of CO2, which is already unlikely in the near future.

      • Greg, we wouldn’t be talking about any of this list if it wasn’t for significant CO2 being added and causing warming already. Yes, some still deny any connection between CO2 and these things.

      • AK, to me a reduction of CO2 levels is much less likely than a significant reduction in the emission rate of CO2, which is already unlikely in the near future.

        IMO that makes you just one more religious nut. There are scenarios that work that way, there are scenarios that involve exponential growth of CO2 removal technology rather than trying to limit fossil fuel emissions. Their relative probabilities are critically dependent on current politics and technical R&D, and how they evolve over the next 5-10 years. I see your statements here as an effort to influence that likelihood, specifically by diverting attention from how easy it would be for “our society” to foster such technology.

        You and Peter Lang belong together: you’re both tech deniers.

      • Jim D

        Agree with you (for a change).

        A reduction in CO2 levels is extremely unlikely, because this would mean a reduction of emissions to well below 50% of current levels, essentially shutting down the world economy.

        This would put emissions back to the level of around 1970, when world population was 3.7 billion (or a bit more than half of today’s 7.1 billion).

        Per capita CO2 emissions have increased by around 10% since then, with most of the increase coming from large developing nations (China, India, etc.). Per capita CO2 emissions of the highly developed nations (USA, EU, Japan, etc.) decreased by over 10% over this period.

        But to reach 1970 emission levels would mean for everyone to reduce per capita emissions to well below half of todays level.

        The Chinese and Indians, etc. are not going to do this and, thereby, endanger the chances of improving the lot of their populations.

        The worst hit would be the underdeveloped nations, whose inhabitants would continue to be deprived the access to a reliable source of low-cost energy in order to pull themselves out of the abject poverty in which they now find themselves.

        So it’s pretty clear that this is just not going to happen.

        Even if all new coal-fired power plants worldwide were replaced with nuclear plants starting today, this would only reduce 2100 CO2 levels by 60 to 80 ppm, out of somewhere around 640 ppmv with “business as usual””, or an arguably exaggerated AR5 “worst high-coal, high forcing, high end climate change case” RCP8.5 of 750 ppmv.

        And this would have an imperceptible impact on global warming to year 2100 of a fraction of a degree.

        So it’s about arm-waving, wailing, lamenting and gnashing of teeth, but, folks we are unable to change our planet’s climate no matter how much money we throw at it.

        Sorry ’bout that.

        Max

      • You and Peter Lang belong together: you’re both tech deniers.

        You too, manacker.

      • AK, as long as China and India keep emitting, which country in their right mind is going to put their own money into extracting other people’s emissions. The economics is just wrong, let alone unaffordable and even uninvented anyway. Now, if the world decided they would pay people as much to remove CO2 as they do for the fossil fuels that put it there in the first place, it might help. Not sure, where the funds would come from without a carbon tax, and that tax would have to be substantial to fund such a deal.

      • @Jim D…

        The economics is just wrong, let alone unaffordable and even uninvented anyway.

        Typical tech denier talk. The “economics” was wrong twenty years ago on all sorts of technology common today. I’ll grant that specific prediction involves a lot of guesswork, but it also interacts with a bunch of technical/political decisions being made right now.

        Just sucking the CO2 out of the air/sea surface isn’t enough. It’s necessary to foster and nourish technology that will be cost-effective to extract CO2 to produce a valuable commodity. I see biomethane as the most likely option, right now, because AFAIK all the necessary technology is either already mature or maturing, or suitable for being ramped onto an exponential cost reduction curve through appropriate (societal) investments in R&D.

        I’ve gone into detail in previous comments at this blog, and don’t plan to waste my time doing it again for tech-deniers, just so they can dismiss it with specious arm-waving.

        There is a variety of other possibilities than biomethane, most of which I would regard as feasible but less likely to compete with it. I’m even less interested in wasting time going into detail over that, although others have (and presumably will continue to).

      • Matthew R Marler

        Jim D: Are you suggesting things are reversible even if CO2 keeps rising? I thought I made a statement of the obvious, but I guess not obvious for some.

        Might be reversible, might not be. What is obvious is not necessarily true. If the effects of CO2 on water vapor and clouds, or the influence of the sun, have been mis-estimated, then reversal of heating is possible.

        Returning to a theme of earlier, my “broken record” message is that the dynamic effects of CO2 and sun are not reliably known: evidence is patchy.

      • AK, since there is no profit associated with removal of CO2, something is needed as a motivation. Trading carbon is one way, but it has to be global, as would a tax, so that the removers can be funded from all the emitters. You see the problem if emissions somehow do reduce, then this fund runs out, then who pays for the continued reduction to safer levels? The economic/political difficulties are at least as hard as the technical ones of mass-scale removal, which is why I give it no chance. But perhaps I should never say never. Severe climate change, after it has happened, may provide enough motivation for these expensive ‘hail mary’ solutions as a necessary course for survival.

      • @Jim D…

        Typical denier behavior. Evidently you didn’t bother to read what I wrote.

      • AK

        Not a “tech denier” at all, AK.

        If new technology is developed that will eliminate the need for fossil fuels entirely at a lower cost than fossil fuels, then fossil fuels will be replaced.

        And I am sure this will occur some time within the next century. That’s why I am not at all worried about “peak oil” (i.e. “peak fossil fuels”).

        But for NOW, we have only one technology that could make a major impact and that is nuclear fission to replace all new coal-fired plants.

        Minor improvements could also result in the transportation sector and in energy conservation actions, but these are small in comparison.

        Over the next 80+ years these could result in a reduction of atmospheric CO2 by year 2100 of 60 to 80 ppmv, out of an anticipated “business as usual” level of 640 ppmv to a “worst case” high-coal, high-forcing high-end climate change scenario of 750 ppmv (IPCC RCP 8.5).

        That’s it, AK.

        That’s why I agree with Jim D that we will not be able to reduce atmospheric CO2 concentrations below today’s levels or even reduce CO2 emissions to half of the current levels in a world with a growing population overall and with the rapid development of giant underdeveloped nations, such as China and India.

        IMO it ain’t gonna happen.

        But that’s just my take on it. You may have different thoughts.

        Max

      • ” Everything listed is irreversible unless a way is found to reduce CO2 in the atmosphere, and there is no way to do that.

        Is this a statement of religious belief?”

        Obviously. It’s “progressive” if you understand that “progressive” are
        lying about what they are. Marxist believe that telling a big lie is much
        better than a small lie. So “progressive” is actually the complete opposite
        of progressive. “Progressive” believe the future is doomed. Rather than progressive which think future brings improvement in the human condition.
        Due to their tendency to support the idea the lying is acceptable, Marxist
        have destroyed any “future” of Marxism. There to similar to the Muslims which believe god wants them to lie.
        Political lie has general rule.
        Diplomats are diplomatic.
        But the left is a religion about everyone of them being politicians. And large part of Islam is about being “political”- the religion will control/govern the people. Very little difference.
        Not a Protestant view, not a view of Age of Reason- it’s the opposite pf the Age of Enlightenment. It’s the view of the dark ages.

      • Not a “tech denier” at all, AK.

        Yeah, a tech denier. IMO you don’t understand how technology has developed over the last few decades well enough to project that development forwards.

        Looking at the movement of costs for solar power, and the development of new, low-cost, technology that could provide synergy and eliminate the need for technology with a slower cost-reduction curve, I’d guess that within 1-3 decades large systems based on concentrated solar PV, electrolytically produced hydrogen storage, and hydrogen fuel cells, will be more than capable of competing with fossil carbon-based systems. Without the need for special subsidies or artificial price supports on fossil carbon.

        IMO a system based on “biomethane” will be ready sooner: it only requires developing the necessary biotech to combine hydrogen with CO2 extracted from the air/sea, probably starting with some alkalineophile methanogen. Because the process does not involve photosynthesis or oxygen respiration, the replacement rate for necessary enzymes will be much smaller relative to the reaction throughput. The necessary energy for extracting the CO2 will be provided by the reaction. An intermediate “capture fluid” at a high pH will carry the CO2 from the air or sea (surface water) to the bio-reactor.

        Note that most of the storage, transport, and power generation technology for methane is already mature, and that a strong reliance on methane could reduce the need for large electrical grids with huge generating plants. Instead, small, easily mass-produced and transported units could be emplaced locally, allowing much faster and more flexible response to changes in demand. It also reduces the risk from solar activity, and probably substantially reduces distribution costs, at least in areas where methane is already distributed for heating purposes.

        While the probability of such technology becoming mature within 3-4 decades is obviously critically dependent on political and technical/financial decisions made today, if the right investment environment is enabled IMO the chance is very high, much closer to 100% than 50.

    • Steven Mosher

      “Everything listed is irreversible unless a way is found to reduce CO2 in the atmosphere, and there is no way to do that.”

      we surely can suck C02 from the air. It’s expensive to do so.

      • Plant more trees.

        So how do we grow more crops on less land?

        GMOs.

      • we surely can suck C02 from the air. It’s expensive to do so.

        For the moment. How fast it becomes how cheap depends on a variety of political and technical/financial decisions being made right now.

      • Harold is right.

        If you really wanted to sequester carbon, one of the most effective methods is to plant fast-growing trees (i.e. Pulp trees) and sequester the resulting wood products where they would not decay and release CO2 back into the environment (like under the clay cap of a landfill).

        It’s not PC, but newsprint in landfills is an effective sequester media…

      • Mosh

        “Sucking CO2 from the air” is “expensive”, as you write. It’s also a non-value added endeavor (unless you combine this with generating something of value).

        Even doing this directly at the emission source is expensive and NVA.

        Pumping it into underground geological formations or the ocean might cause unintended and unforeseen problems, which are worse that the CO2 in the first place. And, again, this would be a NVA endeavor.

        Planting more trees makes more sense (there is added value in wood, and if this is used for non-combustion, the CO2 stays out of the atmosphere). But it won’t make a big difference. You can figure it out for yourself.

        Max

        .

      • Adding value leaves deficit regrets.
        ========================

    • JimD, “Everything listed is irreversible unless a way is found to reduce CO2 in the atmosphere, and there is no way to do that”

      Jim don’t be so pessimistic:

      Going negative: Stanford scientists explore new ways to remove atmospheric CO2

      Reducing carbon dioxide emissions may not be enough to curb global warming, say Stanford University scientists. The solution could require carbon-negative technologies that actually remove large amounts of CO2 from the atmosphere.

      http://news.stanford.edu/pr/2013/pr-reducing-carbon-dioxide-021513.html

      http://gcep.stanford.edu/index.html

  20. There is another way of looking at this report. Pielke Jr. notes that it also walks back the claim that we’ve experienced, to date, any weather catastrophe as a result of AGW.
    So, nothing bad so far, nothing bad for a long, long time means the prudent thing to do is to stop deploying and subsidizing wind and solar (Europe is scaling back now), no new carbon taxes and even repeal recent ones (Australia, Canada and soon to be Europe), allow more exploration for natural gas (the US and soon to be Europe and more), build nukes (the rational).

    The only people opposing the prudent thing to do are climate activists.

    Conservatives, Republicans and even a growing number of environmentalists are already willing to back fracking and nukes and cut back on wind and solar. In short, this could be the first report leading to action with genuine bi-partisan support as long as the activists don’t hijack it again. I have low-confidence of that.

  21. The Official UN-IPCC Scaremongers’ AGW Catechism
    Try at all times to work the following words and ideas to conjure up notions of impending peril, as follows:

    • Abrupt
    • Change
    • Disruption
    • Forcing
    • Tipping point
    • Critical threshold
    • Irreversible
    • Phenomena
    • Perturbed state

    Tip to authors: Always speak in terms of both human and natural to preserve the idea that humanity is unnatural. Use words like ‘substantial’ and ‘significantly’ to infer that your expertise enables you to know the difference between “a lot” and “no big deal.” Whenever possible, write in veiled, dark and foreboding themes; for example, consider saying—e.g., “beyond which abrupt or non-linear transitions to a different state ensues,” as opposed to “as time goes by we can expect to turn many corners” (although you may wish to conjure up anxieties about—e.g., “falling off a cliff” like 14th century ships sailing off the edge of the world).

    • The genius move was from “global warming” to “climate change”. Global warming sounds too much like a good thing. Get rid of winter and cold nights, right on! At least it was almost honest; only almost because the amount of warming would not be detectible except in inflamed imaginations. “Climate change” is dishonest because nobody’s climate classification is going to change in any believable scenario.

    • ““falling off a cliff” like 14th century ships sailing off the edge of the world).”

      Flat-Earth thinking at the IPCC? Monsters with unimaginable impacts lurking just beyond the horizon that will kill everything? A horizon that moves a little further out with each passing year?

      :-)

      I completely agree.

  22. Odds of dying from an asteroid strike: 1 in 74,817,414

    http://www.economist.com/blogs/graphicdetail/2013/02/daily-chart-7?fsrc=scn/tw/te/dc/dangerofdeath

    Thing is an asteroid strike would take out a big fraction of humanity and the Earths biosphere.
    A vibrant economy is the only thing that can save humanity, and the biosphere, from this type of extinction level event.

    • Doc,
      thanks for the opportunity to plug the B612 foundation which is raising $400 million to launch a satellite to search for the civilization killing asteroid. About the amount the Waltons donated to a modern art museum in Arkansas and 1/4 the new SF 49ers stadium in Santa Clara. Maybe we can convince someone to compare risks.

      Scott

    • The odds of a polar bear dying from global warming is less likely than a human dying from global cooling.

  23. Steven Mosher

  24. “The only people opposing the prudent thing to do are climate activists. ”

    Oh , don’t worry, some dyed in the wool ecologists even now believe that carbon dioxide, the basis of life on earth is more toxic to life than ionising radiation.

    Thatcher did a great job of replacing annoying coal miners with subservient technicians.

    It was a skilful piece of political Aikido creating the AGW scam. Used the inertia of the green movement to flip it on it’s head.

  25. Mikey Mannhole.

    They may have taken the dangerous out, but they replaced it with desperate stupidity.

  26. The government apparatchiks, sorry bureaucrats, who b*tch slapped the IPCC for admitting the models were so far off, must have simply missed Section 12.5.5 in the WG1 Report. I am amazed that it was allowed to go through.

    I predict a rapid addendum of some kind to try to mitigate the political damage:

    “Hey, we got the Himalayan glaciers wrong in AR4, same thing happened here.”

    Or the IPCC could shock the world and stand fast on its admission, finally, of ignorance.

  27. Looks like the IPCC may be walking back the prospect of imminent doom for the Amazon as well”

    “In particular, the Amazon forest has been the subject of several studies, generally agreeing that future climate change would increase the risk tropical Amazon forest being replaced by seasonal forest or even savannah (Huntingford et al., 2008; Jones et al., 2009; Malhi et al.,
    2009). Increase in atmospheric CO2 would partly reduce such risk, through increase in water efficiency under elevated CO2 (Lapola et al., 2009; Malhi et al., 2009). Recent multi model estimates based on different CMIP3 climate scenarios and different dynamic global vegetation models predict a moderate risk of tropical forest reduction in South America and even lower risk for African and Asian tropical forests (see also Section 12.5.5.6) (Gumpenberger et al., 2010; Huntingford et al., 2013).”

    AR5 WGI 12.4.8.2

    http://www.climatechange2013.org/images/uploads/WGIAR5_WGI-12Doc2b_FinalDraft_Chapter12.pdf

  28. a little Q & A moment reported in the Bishop Hill thread highlights the gap between emerging scientific realities and widespread hype/alarm:

    report at Bishop Hill blog on meetings sponsored by Royal Society

    This prompted me to put a question to him, which was the first I’d been able to raise via the chair all day (I’d tried in several talks). I said to Matt:

    “What the IPCC says, and what the media says it says are poles apart. Your talk is a perfect example of this. Low liklihood and low confidence for almost every nightmare scenario. Yet this isn’t reflected at all in the media. Many people here have expressed concern at the influence of climate sceptics. Wouldn’t climate scientists’ time be better spent reining in those in the media producing irresponsible, hysterical, screaming headlines?”

    Tumbleweed followed for several seconds. Then Matt said:

    “Not my responsibility”.

    [emphasis added]
    The IPCC and many climate scientists face a “credibility gap”….. angry alarmists can disparage people who point this out, but those of us not welded onto a team bus already cannot help but notice this…..

  29. But don’t worry all you CAGW groupies. The band hasn’t broken up yet.

    WG 1 still predicts:

    “increase in hot extremes and decrease in cold extremes” 12.4.3.3

    “very likely heat waves will occur at a higher frequency” 12.4.3.3′

    “more intense storms” 12.4.5.5

    and

    “‘extreme’ drought as the normal climatological stand by the end of the 21st century” 12.4.5.5

    So you still got that going for ya.

    And there’s still hope. If I recall, the really juicy scare mongering was in WG 2’s work in the AR4.

  30. Chief Hydrologist

    ‘Abrupt changes that arise from nonlinearities within the climate system are inherently difficult to assess and their timing, if any, of future occurrences is difficult to predict. Nevertheless, progress is being made exploring the potential existence of early warning signs for abrupt climate change (see e.g., Dakos et al., 2008; Scheffer et al., 2009).’

    That’s pretty funny really if you know the Dakos or Scheffer papers. Progress in tiny baby steps. A perspective on how difficult this task is would help.

    Catastrophic climate change happens all the time. ENSO is a quasi bistable, bifurcating system – and changes are generally catastrophic for someone. Decadal shifts in surface and ocean temperature, biology, hydrology and arctic ice are apparent. Predicting the timing and limits – or even direction – of the next shift is quite impossible.

  31. Antonio (AKA "Un físico")

    Off topic. My analysis against IPCC’s claims on climate change:

    https://docs.google.com/file/d/0B4r_7eooq1u2VHpYemRBV3FQRjA

    There is a important concept about statistics & climate.

    • Figure 9.5 is very odd and quite astonishing. It suggests that all the aerosol/sulphate/black carbon effects are trivial; thus, aerosol/sulphate/black carbon cannot be used to justify the current pause in the temperature rise.

      http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-9-5.html

      • Steven Mosher

        you know what is REALLY WEIRD about that chart that I never noticed before?

        Look at the trend for natural forcing only. Why does it trend down after 1960? Huh?

        Look at the HUGE dips. You know what? you know why that natural forcings looks so bad? ALL the models over respond to volcanoes.

        As far as I know nobody has looked at the natural forcing runs with any critical eye.. WTF?

      • The higher the sensitivity to CO2 the lower the temperature would now be without human ghgs.
        =============

      • Steve, the aerosol effects are huge as you say. However, at present atmospheric aerosol levels are very low indeed, with the OD550 being lower than anytime in 30+ years.
        As the models are tuned to respond to aerosols, but reality isn’t, we can understand part of the reason for the model/reality divergence.
        A decade without a major volcano is going to destroy the models.

  32. Pingback: Judith Curry says it’s okay | Wotts Up With That Blog

  33. While a little off-topic, I posted this over at Realclimate, though it will be interesting to see if it gets through moderation. I think if you believe the models and the IPCC reports, it would be dangerous to not have that warming CO2 in the atmosphere, because it would be really cold. Note, they also have a graph at realclimate showing the temps @ 1900 as being coldest recorded, which means things would be frigid without the CO2. Looking forward to notes of significant errors in the back of the envelope calculations below.

    I’ve been wondering what temperatures would look like today in the absence of CO2, and assuming the models are correct.

    Figure 9.5 of AR-4 indicates temperatures without CO2 forcing would be the same as the 1900s, in the year 2000.

    figure 1.4 from the second order draft of AR5 indicates AR4 models would increase temperatures up to .4 degrees between 2000 and 2013 using the eyeball (and paper) method (note the zero baseline of the two graphs is different), yet temperatures have not increased, so presumably some natural variation sucked out extra heat.

    This means temperatures could be up to .4 degrees colder than in 1900. This historical temperature graph puts the 1900s about .2 degrees “C” above the historical low. Doing the simple math from the IPCC papers, this means the temperatures would be up to .2 degrees lower than in recorded history.

    It seems to me this is a reasonable back of the napkin calculation.

    A) Does anyone know whether AR5 has a similar graph to AR4?
    B) Anything obviously wrong in the above calculations?

    • Ed

      Never convinced by this ‘ global’ average showing such a low point around1900

      Here is CET –a reasonable proxy for northern hemisphere temperatures graphed against BEST.

      Putting 1900 in a broader historical context demonstrates that it can’t really be called part of theLIA? As regards forcing Phil jones reckoned that the 1730 decade was very similar in temperature to the 1990’s
      Tonyb

      • Judith worked with Muller on BEST, didn’t she? I thought there was some kind of disagreement with the method.

        In any event, I’m working within the confines of what the IPCC is saying. That’s the given: Assume the IPCC is right. What are the implications?

        The implication to me is it’s good we have this CO2 floating around.

      • Ed

        Assume the IPCC is correct?

        Here is CET from 1538 to the present day( my reconstruction 1538 to 1659)

        http://wattsupwiththat.com/2013/05/08/the-curious-case-of-rising-co2-and-falling-temperatures/

        It shows numerous ups and downs. The mwp and the roman warm period appear to be warmer than the present. The Minoan warm period was substantially warmer than today when many of the glaciers melted. Temperatures are currently declining sharply. Note the co2 line.

        If co2 has any effect it seems to be a minor passenger in the agw bus and not the driver
        Tonyb

      • What point are you trying to make with the CET plot? Don’t assume everyone sees the same implication you do.

        My first observation is that it’s yet another example (if any more were needed) of why it totally stupid to fit straight lines to climate. Sadly most people’s data processing techniques don’t seem to get beyond running means and trend fitting.

        Second : apples and oranges . If you fit CET over the same period the slope will be similar. You may as well fit two slopes to CET , second half and full data set. Then you would discover it’s nothing to do with CET/BEST , it’s the fitting periods. The old cherry tree problem again.

        Odd the way your crappy BEST moving average is so far outside the data in 1780. Whatever you do to pad the end is illegit. OMG you have not even centred your runny mean. You’ve done an economists end-of-period average introducing a phase shift. That’s whey 1780 misses the actual data.

        http://climategrog.wordpress.com/2013/05/19/triple-running-mean-filters/

        Well, congratulations you seem to have managed to get most of the basic DP errors into one graph. I’ll bookmark this one for next time I need an example of what not to do.

        BTW ICOADS SST has a warmer late 1800’s until Hadley remove 67% variability from the data for HadSST3. Larger variability and cooling does not fit preconceptions. Can’t show evidence of natural variability, data must be wrong.

        ACE (cyclones) corroborate the 1910 dip so I think it’s real, at least in NH:

        http://climategrog.wordpress.com/?attachment_id=215

        CET is interesting as a long record but what reason do you have to say it is somehow representative of the whole NH?

      • Greg

        Runny mean?

        Natural variability appears to be a better answer than co2 .phil jones wrote that natural variability was greater than he had perhaps thought. He cited the 1730 decade as being especially warm.

        I have previously cited a variety of scientists as stating that cet has a good but by no means perfect correlation with northern hemisphere temperatures.

        I am drawing together the various statements and comparisons with data sets for a future article.

        What is your explanation for the considerable variability we can observe in the long temperature records?
        Tonyb

      • Steven Mosher

        “Odd the way your crappy BEST moving average is so far outside the data in 1780. ”

        Another idiot comment from greg.

        The BEST Data at 1780 is the average of the entire field. the small patch of england tony refers to as well as most of europe and some of north america.

        Tony is comparing CET ( a few square miles) to a much larger area.

        That location (CET) along with a few others has reasonable correlation with the entire globe, although with CET ( and others) you will find years in which it is at odds with the rest of the world.

        In other words, the thing you point out is expected and not anything odd.

      • Goodman has a point in avoiding filters that lose the underlying information content.
        Instead of the classical filter, the actual temperature record should be compensated by known sources of noise:

        http://contextearth.com/2013/10/04/climate-variability-and-inferring-global-warming/

    • In terms of CO2, the difference between the Ice Ages and now is about a factor of two. Does that help, or make you wonder what another factor of two does on top of that?

    • BarBar said
      “I think if you believe the models and the IPCC reports, it would be dangerous to not have that warming CO2 in the atmosphere, because it would be really cold. ”

      I accept solid science, because I believe in mankind’s collective intelligence.

      This is a mapping of the temperature (with the noise removed )mapped against CO2.

      Look at the bottom ECS plot and note the log-regression best fit formula. The temperature anomaly goes down another 25C as the CO2 approaches 1 PPM. This is close to how cold the earth would be if we didn’t have CO2 as a control knob (to use Lacis’ term).
      Yet the ECS of 3C for doubling of CO2 is enough to keep Earth’s troposphere fit for lifeforms.

      Don’t you feel lucky?

  34. “In that context, most aspects of the climate change resulting from CO2 emissions are irreversible, due to the long residence time of the CO2 perturbation in the atmosphere and the resulting warming (Solomon et al., 2009).”

    Where Is the proof that a warming cycle is irreversible? Not according to data from Antarctic ice core samples.

    • Leonard Weinstein

      Nabil,
      I do not accept the “significant” warming due to CO2 as a problem, but let us consider a toy problem: Assume that any CO2 level increase is claimed to causes an immediate heating and a claimed long slow eventual added heating, and the eventual amount of heating depends on the amount of CO2 left after a long while. Assume any sustained level of 800 ppm is claimed to cause a rise of 2.5C in the short term, and an additional 2.5C over a century. This is a 5C rise, and if true is a possible problem. Now assume the level went to 800 ppm, but when it reached that level there were large CO2 reductions in production. Assume with greatly reduced production a 7 year period is needed to drop the level to 1/2 of the excess over 290 ppm (the so called good level). Thus after 7 years we are back to 545 ppm, and at 14 years to 417ppm, only slightly over present levels. If we went to a third 7 year period, we would be only 21 years out, but the level would be about 385 ppm. It would take hundreds of years to come very close to 290, but (almost) no one claims that even 385 ppm is a big problem. If we cannot measure any source of storage that can add a huge temperature at 385 ppm, at some later time, it is clear that just 21 years completely eliminated the problem. In addition, since we have already passed that level to over 400 ppm, and there is no storage seen that can affect us in the future more that 0.06C (the actual deep ocean temperature rise), there is no long-term effect that happens independently of the level of CO2. In fact there is no demonstrated warming that can be shown to be due even to the present 400 ppm. The entire tail wagging the dog on long term heating is a myth.

    • Leonard Weinstein

      Sorry Pekka, but I think you are wrong. I don’t know the exact time for one cut of 1/2 of the excess, but if you take the downside slope of the yearly variation, you get an idea how fast the ecosystem and ocean dissolving can act. If you also observe that about 1/2 of the added new excess is removed each year nearly independently of the level, you can estimate the net removal rate. If you stopped adding excess, that removal rate would still apply. It is based on biological and solubility effects, which only depend on present levels, at least for the excesses to present. It would result in between 5 and 15 (or so) years per 1/2 of excess, at least down to levels around 350 ppm, in the absence of new added excess. If you have a valid argument that shows this is wrong, and not some model that looks at ideal rates, rather than directly indicated measurements, please tell me. I just used 7 years as an example, and it may be higher, but the point is that it would drop fairly quickly at first, and the level is all that matters, not where it has been. Also do you have a magic way where the long term effect is hiding. It is not a lack of equilibrium effect, and it can’t hide in the ocean. Where do you propose it is.

      • Leonard Weinstein

        Pekka,
        I think I see the disagreement with your curves. The amount remaining (above zero) is not the reference, the level of 290 ppm is the so called equilibrium ideal level (where removal stops). At 800 ppm, the level of 290 ppm is the 36% level on your curve. For your curve, If we start at 800 ppm, the 100% goes to 72% of initial level in about 15 years, and that is half of the excess.

      • Leonard Weinstein

        I meant 68% not 72% for the 1/2 level of excess.

      • Leonard,

        The annual variations have their own reason. That’s the large variability in the terrestial biomass, more specifically in the biomass of tropical forests which react to El Nino / La Nina. Variation in the rainfall is the most immediate reason for that. That kind of annual variability is present whether the CO2 concentration is increasing over long term or not, and that doesn’t tell much if anything about the removal of extra CO2 from the atmosphere.

        To learn about removal of additional CO2 from the atmosphere different signals must be considered. Looking only at multi-year averages helps, when the period is long enough to make the short term variability less important, but that cannot tell about fast response to changes in CO2 concentration. To estimate that some other way must be figured out to separate that response from the influence of weather patterns. Some kind of models are needed for that. Using them together with more detailed data on geographic distribution of the variability gives some results. After all that some uncertainty remains and that’s one source of the wide error bars of the figure of AR5 I gave the link to.

      • David Springer

        Leonard Weinstein | October 3, 2013 at 6:53 pm | Reply

        “Sorry Pekka, but I think you are wrong. I don’t know the exact time for one cut of 1/2 of the excess, but if you take the downside slope of the yearly variation, you get an idea how fast the ecosystem and ocean dissolving can act. If you also observe that about 1/2 of the added new excess is removed each year nearly independently of the level, you can estimate the net removal rate. If you stopped adding excess, that removal rate would still apply.

        My bold.

        Exactly right. A point I have been making for years. Obviously there’s a natural equilibrium point of 280ppm during interglacials which is very likely dependent on average ocean basin temperature. Forcing more CO2 into the atmosphere does very little to raise ocean temperature so the equilibrium point doesn’t really change. Therefore the faster you pump up atmospheric CO2 the harder the ocean tries to suck it back out. So we end up with a constant rate of 50% sequestration per annum of the excess regardless of the magnitude of the excess. Should the excess stopped being pumped into the atmosphere sequestration will continue to occur with the system moving back towards the equilibrium point of 280ppm. The rate of sequestration will decelerate as the excess is reduced.

        This is almost blindingly obvious and destroys the unsupportable meme that anthropogenic CO2 has a lifetime of centuries or more. Patently false. Absent continued emission it will be removed at the same rate it accumulated making its lifetime, for the majority of it, on the order of several decades.

        +1

      • The retrenchment will probably proceed faster because of entrained negative feedbacks.
        ==============

  35. Skeptics have long acknowledged that geoengineering is dangerous. Whether through pumping aerosols into the atmosphere to reflect the Sun, or dumping iron into the oceans to try and make it absorb CO2. Skeptics balk when such a new harebrained geoengineering scheme is suggested. What if it goes wrong? they ask, How do the scientists know there won’t be side effects? What about the law of unintended consequences?? fear, panic!

    Of course the biggest harebrained geo-engineering scheme that has already started is the scheme of pumping a trillion tons of CO2 into the atmosphere to lift CO2 levels to highs not seen for 20 million years. Skeptics of course suitably aghast of the danger of doing this.

    • Generally, skeptics don’t want their earnings taken from them to do anything that the Left has a wet dream about. Many Westerners have learned that following the Left down any path is a dead end and we see in so many ways that the psychosis, hypocrisy and self-defeatism of global warming alarmism is another obvious example of the Left leading society off a cliff.

      “But, I digress. My main point is that nothing stands in the way of a popular theory (e.g. global warming) better than failed forecasts. We are now at the point in the age of global warming hysteria where the IPCC global warming theory has crashed into the hard reality of observations. A few of us are not that surprised, as we always distrusted the level of faith that climate modelers had in their understanding of the causes of climate change.

      “I continue to suspect that, in the coming years, scientists will increasingly realize that more CO2 in the atmosphere is, on the whole, good for life on Earth. Given that CO2 is necessary for life, and that nature continues to gobble up 50% of the CO2 we produce as fast as we can produce it, I won’t be that surprised when that paradigm shift occurs, either.” ~Dr. Roy W. Spencer

    • Leonard Weinstein

      lolwot, The claim CO2 level is higher than seen for 20 million years is possibly true, but even there I am somewhat skeptical, as tree leaf stomata disagree with ice cores somewhat, and short periods (even thousands of years long at long ago time periods) of large variation are not resolved. However, prior to 20 million years ago, other geological data strongly supports the fact that through most of the last several hundred million years the CO2 level was much higher than even the projected increase at the near future. Over much of that time the Earth was particularly rich in biodiversity. In fact evidence indicates that CO2 level and temperatures were not correlated. I consider this more than adequate to show the higher level of CO2 is not a direct threat. It may (or may not) cause higher sea level, but slow rise over thousands of years. Considering where we were thousands of years ago, I don’t think that is an issue. Also consider that if we are near the end of the Holocene (in agreement with other recent interglacials) cooling is the real danger, so if CO2 delays that it is great. Since the only demonstrated effect of recent warming and increased CO2 has been a more productive Earth, where are you coming from?

      • 1) You point out that life was just fine when CO2 was much higher in the past. But in terms of impacts and room for adaptation it is the rate of change that matters not the absolute amount. If CO2 rises from 280ppm to 800ppm over a million years life (including humans) would have time to adapt, the surface oceans would have time to buffer, etc. 300 years, not so much.

        2) You state that CO2 level and temperatures were not correlated in the past. I have heard this claim before, but never seen it sufficiently substantiated. Other factors have to be taken into account, such as the fainter Sun the further you go back in time as well as the incomplete picture of the temperature and carbon records.

        3) You ask me to consider that cooling is the real danger because we are near the end of the holocene. You say if CO2 delays that, it is great. But odds are that the fall into the next glacial will happen long after the AGW peak. How AGW can make the situation worse – if we are really unlucky – is if AGW pushes the world to a superinterglacial warmth onl to let the world plunge into a glacial from a higher level causing a larger impact.

      • “1) You point out that life was just fine when CO2 was much higher in the past. But in terms of impacts and room for adaptation it is the rate of change that matters not the absolute amount. If CO2 rises from 280ppm to 800ppm over a million years life (including humans) would have time to adapt, the surface oceans would have time to buffer, etc. 300 years, not so much.”
        Humans and animals are currently living in environments higher than 800 ppm.
        Cities have higher CO2 levels.
        Meeting or parties with more than dozen people in a room have higher levels. Laws have been passed limiting school children from being in classrooms with CO2 levels considerable higher than 1000 ppm [I don't there in any rules about levels of CO2 1000 ppm or lower- but laws vary
        in terms some threshold above 1000 ppm]. With submarine and say ISS
        have quite high limit- thousands of parts ppm CO2 [it's nothing to do with fires or accidents, btw- it's about normal operational conditions].
        When you sleep, you experience very high levels of CO2. When animal sleep they could experience high levels- ants and bees affect their environment of their nests to control CO2 level and levels are maintained at quite high levels
        Etc.

    • lolwot

      The BIG difference between hare-brained geo-engineering schemes, such as those you mentioned and burning fossil fuels to provide accessible low-cost energy and transportation to drive the world economy, is that the geo-engineering schemes are costly but DO NOT ADD INHERENT VALUE.

      They are non-value added endeavors, while burning fossil fuels provides the energy needed to maintain and grow the world economy in order to ensure humans the high quality of life and long life expectancy we (in the developed world) now enjoy. And to achieve this in a world with a growing population and large developing economies, such as China and India.

      BIG difference. lolwot.

      Max

      • The utility of a geo-engineering scheme has no bearing on the danger.

        We don’t see skeptics saying AGW is dangerous but we should do it anyway. We see skeptics claiming AGW isn’t dangerous.

      • AGW isn’t dangerous. CAGW would be, if it were an accurate description of reality. It’s not.

      • lolwot “We don’t see skeptics saying AGW is dangerous but we should do it anyway. We see skeptics claiming AGW isn’t dangerous.”

        That is not true. Quite a few skeptics don’t have any issue with taking reasonable action. Banning everything and requiring government mandates without having a clue how much good they will do is not reasonable. Land and watershed restoration/conservation is a win-win, no heartburn there. Wind and Solar without ridiculous government venture capital action is fine but the users/owners have a stake in how what and when. Forcing utilities to pay for over priced and intermittent power is just plain un American. Cleaner coal and cleaner natural gas until a more alternate energy friendly infrastructure can be adopted, is just a fact of life.

    • “Skeptics have long acknowledged that geoengineering is dangerous. ”

      Can be dangerous.
      Driving a car can be dangerous.
      And btw, having government drive your car, would be something foolishly
      dangerous.
      If you must have to have governments doing geoengineering, one should be extremely cautious in how this is to be done. But even so, probably a bad idea, due to the general tendency of government not being accountable for it’s actions. Just look at recent history of UN, as treasure trove of unaccountable behavior of government. And you look at US government, US congress, see how it’s has and is acting. One doesn’t need to look at extreme examples such as available from actions of China or EU.

      But governments can govern, and could lead the way to geoengineering being done. So small scale tests conducted by the governments regarding ocean fertilization is not dangerous. As “Nature” has been and is doing this on much larger scale.

  36. The Society of Environmental Journalists will be hosting a meeting on Friday that will discuss the media coverage surrounding global warming.

    The panel will include Joseph Romm with ClimateProgress.org Daniel Grossman, contributing editor, National Geographic News Watch; ; Peter Dykstra with Environmental Health News and The Daily Climate; Katherine Bagley with InsideClimate News.

    The description of the panel on global warming and the media reads: “Have We Blown it? How well has the media done in reporting on this issue? How can it do a better job in the future?”

    “Many critics have accused mainstream media of confusing the public by reporting this topic as if the small (and often industry-funded) ‘skeptics’ were as credible as researchers representing the scientific consensus. This phony balance between real scientists and skeptics appears less common now,” the event’s pamphlet reads. “But many people say that journalism is still doing society a disservice, by under-reporting and downplaying the seriousness of the threats of global warming. We’ll look for lessons and advice from people who follow this issue closely.”

    “Al Gore: US Media ‘Intimidated, Frightened’ on Climate Change”

    “Al Gore ripped U.S. television coverage of climate change Friday, alleging the media is cowering before industry-funded global warming ‘deniers.'”
    “‘Here in the U.S., the news media has been intimidated, frightened, and not only frightened, they are vulnerable to distorted news judgments because the line separating news and entertainment has long since been crossed, and ratings have a big influence on the selection of stories that are put on the news,’ Gore said in remarks at the Brookings Institution.
    ‘And the deniers of the climate crisis, quite a few of them paid by the large fossil fuel polluters — really it is like a family with an alcoholic father who flies into a rage if anyone mentions alcohol, and so the rest of the family decides to keep the peace by never mentioning the elephant in the room. And many in the news media are exactly in that position,’ the former vice president said.”

    http://www.sej.org/headlines/al-gore-us-media-%E2%80%98intimidated-frightened%E2%80%99-climate-change

    It looks like they lost their audience:
    In the Pew Research Center’s annual policy priorities survey, released Jan. 24, just 28% say dealing with global warming is a top priority for the president and Congress this year, little changed from the 30% that said this when Obama first took office in 2009. Nearly four-in-ten Democrats say global warming should be a top priority, compared with just 13% of Republicans. About three-in-ten independents (31%) say this as well.

    http://www.pewresearch.org/key-data-points/climate-change-key-data-points-from-pew-research/

    • “Journalist” another word like “science” subjected to Orwellian word destruction by the parties listed.

  37. There was a time when I worked in a clinic and, uh, one day a young woman came in, she was in her early twenties for a routine checkup and, I said what‘s going on with you and she said I‘ve just become blind. And, I said, oh my gosh, really, when did it happen, she said, well just, uh, coming into the clinic, walking up the steps of the clinic I became blind. And I said, oh, and I‘m—by now I‘m looking through the chart and I said, well, has this happened before, she said yes, it‘s happened before. I‘ve become blind in the past, and, what she had of course was hysterical blindness. And the characteristic of that, is that, the severity of the symptom is not matched by the emotional response that‘s, that‘s being presented. Most people would be screaming about that but she was very calm, oh yes, I‘m blind again. And I‘m reminded of that whenever I hear, that we‘re facing, whether we wanna call it a crisis or not, a significant global event, of, of, of importance where we‘re gonna have species lost and so on and so forth— that we can really address this by changing our light bulbs. Or that we can really make an impact by unplugging our appliances when we‘re not using them. It‘s very much out of whack. And so if… we’re only gonna do symbolic actions, I would like to suggest a few symbolic actions that right—might really mean something. One of them, which is very simple, 99% of the American population doesn‘t care, is ban private jets. Nobody needs to fly in them, ban them now. And, and in addition, [APPLAUSE] let‘s have the NRDC, the, the Sierra Club and Greenpeace make it a rule that all of their, all of their members, cannot fly on private jets, they must get their houses off the grid, they must live in the way that they‘re telling everyone else to live. And if they won‘t do that, why should we. And why should we take them seriously. [APPLAUSE] ~Michael Chricton

    • A fan of *MORE* discourse

      Michael Crichton misdiagnoses the symptoms of “ hysterical blindness  scintillating scotoma

      The latter being far more common than the former.

      A clinical pearl  Whenever you hear hoofbeats, think ‘horse’ not ‘zebra’.

      It appears that Dr. Crichton’s talents lay with fiction, not medicine. It is a pleasure to help increase your medical acumen, Michael Crichton.

      \scriptstyle\rule[2.25ex]{0.01pt}{0.01pt}\,\boldsymbol{\overset{\scriptstyle\circ\wedge\circ}{\smile}\,\heartsuit\,{\displaystyle\text{\bfseries!!!}}\,\heartsuit\,\overset{\scriptstyle\circ\wedge\circ}{\smile}}\ \rule[-0.25ex]{0.01pt}{0.01pt}

      • Chrichton is drawing a comparison to PFA (Pseudofraidy affect), also known as Kalimeraphobia or Labilephobia. PFA refers to a neurologic disorder characterized by fear of a hotter, more intimidating world than it actually is prompting a desire for more protection than is warranted by any actual threat.

      • David Springer

        Scintillating scotoma produces an aura not blindness you incompetent lying peabrain.

      • Kibbitzers call it as they see it; the patient reports blindness.
        ============

      • Heh, fan oh fan, here’s a neurological disorder thar seemed
        ter be brought on by a cooling world. In his book, ‘Rats, Lice,
        and History,’ H. Zinsser speaks of the outbreak of St Vitus’
        Dance, strange seizures attributed to the terror of The Black
        Death, ‘mass hysterias brought on by terror and despair, in
        populations oppressed, famished and wretched’ to a degree
        unknown in the western world today.
        bts

  38. Meme metamorphosis;

    “Mass extinction “may” have already begun…”

    http://thinkprogress.org/climate/2013/10/03/2725431/unprecedented-ocean-acidification/

    Integrating Fracking to AGW…….had to happen;

    http://thinkprogress.org/climate/2013/10/02/2708911/fracking-ipcc-methane/

  39. So what if abrupt climate changes are due to Milkanovitch cycles?

    Assume for a moment that almost nothing we could do the composition of earth/atmosphere makes any difference to the net result of cyclic heating and cooling 24 hour cycles. (If someone knows a mechanism by which warming is enhanced in the daytime and cooling is retarded in the nighttime, please provide experimental physical evidence.)

    With the influence of increasing obliquity, the earth’s pole in the sun for 6 months melts more ice. More water increases absorbance, which causes warming, which melts more ice and so on. This is a real positive feedback climate cycle which lasts for 6 months.

    So at the opposite pole, the same thing happens. Meanwhile, the hot water rising causes an ocean current towards the cooler pole as cool water fills the space left by the rising heat.

    Warmer oceans over earth increase evaporation and therefore cloud cover. Clouds reflect the sunlight and IR but make no net difference to the radiative heating and cooling over day length cycles. Only when the cloudcover stretches over the poles does it start to provide a negative feedback to the 6 montly polar warming cycle.

    So we can put that information in a GCM and see what it does.

  40. That link on fracking leaking methane is interesting. The first fault I found when reading the newly released AR$ SPM in 2007 was their under-estimation of the impact of methane. Methane is also a long way below saturation, so the levelling off that makes changes either way in CO2 fairly unimportant does not apply to methane.

    Now one thing the does roughly correlate to the ‘slow down’ is atmospheric CH4 which also levelled off.

  41. Blouis: ” This is a real positive feedback climate cycle which lasts for 6 months.” “please provide experimental physical evidence.”

  42. Table 12.4 is the most reassuring part of the AR5 report. It reassures us that it is very unlikely that any “abrupt” or “irreversible” catastrophes will result from AGW. This appears to be a change from the previous AR4 report, which outlined in some detail the potentially catastrophic changes we would see by 2100.

    It is surprising to me that this table made it past the editors’ reviews into the final report.

    The only predicted change that has any reasonable likelihood of occurring according to Table 2.4 under a “worst case scenario” is a late-summer Arctic ice extent that will be under 1 million square km by mid-century, compared to a late-summer 1979-2000 baseline level of 7 million km^2.

    For comparison, this year’s end-September level was 5.35 msk and, if the trend since 1979 continues, we would reach the “zero level” of 1 msk by year 2091.

    For some reason, I’m neither impressed nor frightened.

    But, of course, this message is not the one that IPCC wants to pitch in its AR5 report.

    Nor is it the one that the media will propagate.

    Max

    • “It reassures us that it is very unlikely that any “abrupt” or “irreversible” catastrophes will result from AGW.”

      Permafrost carbon release is listed as irreversible. It doesn’t say that is “very unlikely”.

      Tropical forest is listed as abrupt, and again it doesn’t say that is very unlikely.

      Perhaps you meant to say “abrupt AND irreversible” rather than OR? In which case I disagree that it takes both categories to be a danger.

      Additionally, when it lists something as reversible in eg years to decades (eg with arctic ice), that probably hinges on emission reductions. So if the idea is that AGW is not dangerous if emissions are reduced, I agree.

      • lolwot

        – Permafrost release is stated to be possible with low confidence.

        – IPCC also shows low confidence in projections of tropical forest collapse.

        “Low confidence” = unlikely to happen.

        Don’t worry about these things, lolwot. It’ll only make you sick – for nothing.

        It’s also “possible” (with” low confidence”) that we enter a new Little Ice Age, but I’m not going to worry about it.

        Max

      • Low confidence works both ways. It means you can’t say it is unlikely not to happen.

    • lolwot

      I have “low confidence” that I am going to be hit in the head and killed by a piece of space debris.

      So I don’t avoid the outdoors at all costs and fret about it.

      But, hey, if you want to worry about “tropical forest collapse” or “permafrost carbon release”, go right ahead and do so.

      Just don’t expect others to join you in your anxiety.

      Max

      • Next time you see somebody walking down the street wearing a motorcycle helmet…

      • You claimed that AR5 “reassures us that it is very unlikely that any “abrupt” or “irreversible” catastrophes will result from AGW”

        It doesn’t. Low confidence doesn’t mean unlikely.

  43. Without the word ”dangerous” politicians are inefficient in imposing new taxes http://globalwarmingdenier.wordpress.com/unavoidable-two-hurdles-to-cross/

  44. Don’t miss Pielke, Jr. comments on AR5 and “extreme” weather issues wrt climate change:

    http://wattsupwiththat.com/2013/10/03/pielke-jr-agrees-extreme-weather-to-climate-connection-is-a-dead-issue/

  45. In view of past performance is anyone listening to the IPCC anymore?

  46. Do Not Cite, Quote or Distribute Except to True Believers of the AGW Faith

    ~Fifth Assessment Report Climate Change 2013: The Physical Science Basis, 30 September 2013

  47. AR5 terminology not withstanding, why, where, when, how, and under what circumstances does global warming deserve or merit the label of ‘dangerous’? Perhaps it is all a matter of semantics. What if it isn’t?

    Attaching the label of ‘dangerous’ to something people don’t fully understand is not likely to help them understand the problem any better, particularly when it is not clear who will be affected, how they will be affected, and when. Hence, such labels tend to be a side issue, and that provides little clarity.

    What would be more important than coming up with a label is to first understand the problem at hand. One look at the available temperature record is that global temperature has risen by about one degree C over the past century. Over the same time period atmospheric CO2 has from about 280 ppm to near 400 ppm. This looks like circumstantial evidence that the temperature increase and the CO2 increase might be related. Is that good or bad? Nothing really drastic has happened to the environment so far. Could things eventually become dangerous if atmospheric CO2 continues to increase? There is a great deal of uncertainty and ambiguity in this ‘statistical correlation’ based analysis approach.

    There is a much improved perspective on the global warming problem if we approach the problem in terms of the basic physics that enable the climate problem to posed as a cause-and-effect problem. That is precisely what climate GCMs make possible.

    The basic results of this climate model analysis are that: (1) it is increase in atmospheric CO2 (and the other minor non-condensing greenhouse gases) that control the greenhouse warming of the climate system; (2) water vapor and clouds are feedback effects that magnify the strength of the greenhouse effect due to the non-condensing greenhouse gases by about a factor of three; (3) the large heat capacity of the ocean and the rate of heat transport into the ocean sets the time scale for the climate system to approach energy balance equilibrium.

    There is substantial uncertainty in the rate of heat transport into the deep ocean, and in the rate of polar ice cap melting. This affects the time scale of how rapidly the climate system approaches equilibrium, but has little effect on the equilibrium temperature that the climate system is being forced toward. There is some uncertainty in the water vapor and cloud feedback strength, but this is not a serious uncertainty since water vapor and clouds are constrained by the Clausius-Clapeyron relation, and since the SW and LW radiative effects of clouds cancel each other to a large degree.

    There is also the geological record to take into account which documents the lockstep relationship between atmospheric CO2 and global temperature over multiple ice age / interglacial cycles. A point to note from the geological record is that polar ice caps appeared about 3.5 million years ago when atmospheric CO2 had decreased to about 450 ppm (it is about 400 ppm right now).

    Despite AR5 terminology manipulation, there are actually a number of dangers to contemplate. The sea level rose by about a foot over the last century. The projected 3-foot rise by the end of the century would bring dangerous conditions to low-lying areas of New Orleans, Miami, New York, Baltimore, and many other coastal cities. Intensified heat waves, droughts, and other weather extremes would also bring increased danger to affected areas.

    Just how ‘dangerous’ are these global warming side effects? Probably not all that dangerous if they pass you by. But if you happen to get hit, ‘dangerous’ could well become catastrophic.

    If you want to look further downstream, consider that there are large reservoirs of CO2 currently locked up in the biosphere, soil, permafrost, and ocean, including also large amounts of CH4 residing in methane clathrates. These CO2 reservoirs are temperature dependent, perhaps with a threshold. If humans continue burning fossil fuel at present rates for another century or two, they may reach the point where outgassing from these CO2 reservoirs will exceed the capacity of human control. At that point, humans will have screwed the pooch with their climate. And the Earth will have become the good ship Titanic with no option for rescue. The endgame for a scenario like that could take many centuries to complete. That would be a ‘dangerous’ danger that is not beyond the realm of possible.

    • A Lacis, what if “climate change” appears to be just mainly a multi-decadal natural fluctuation? Does it ever cross your mind?

      • Edim,
        It isn’t a multidecadal fluctuation because that would violate energy conservation. Where would that heat come from?

        Most of the fluctuations revert to a mean of zero. That means that the noise can be removed from the noisy temperature curves and leave behind the trend:

        http://contextearth.com/2013/10/04/climate-variability-and-inferring-global-warming/

        This analysis gives 2C for TCR and 3C for ECS.

      • Chief Hydrologist

        Let me Google that for you – http://lmgtfy.com/?q=interdecadal+Paciic+oscillation

        You are profoundly anti-science.

      • Whut, you don’t know that and are speculating. It’s an argument from ignorance. The consensus is now accepting the multi-decadal fluctuations (the ~60 year pseudo cycles) as very significant for global temperature indices. The next step is to accept the longer pseudo oscillations.

      • I asked the same question at BH to Tamsin Edwards and here’s the answer:

        “Yes, absolutely we do think about it. For example, I recently came across several papers from the late 1980s and early 1990s considering whether the observed changes could be natural variability alone. We continue to do so. ”

        I am glad to hear that climate scientists are considering whether the observed changes could be natural variability alone! That they have to check the old papers (before AGW alarmism) is telling. Thanks for answering Tamsin!

      • EDim The Chief,
        In case you had not noticed, My analysis corrected for the yearly and decadal wiggles that average to zero.

        The residual shows nothing but noise left.

        It’s funny to watch you desperately chasing phantoms. Must be part of your culture, the belief in the paranormal, etc. Typical voodoo science that you adhere to.

      • Whut, you show nothing but noise. It’s your blather that averages to zero.

      • Edim, natural decadal variations including the PDO are about 0.2 degrees at most, even when they reinforce each other. You see that this has no impact when climate change is going to be about 4 C, don’t you? OK, it may be 3.8 C, so what? This is where your disconnect is with the natural variability stuff: scale.

      • Jim D, all of the variability is natural (non-anthropogenic) – that’s the null hypothesis. I have not seen any convincing/plausible evidence of AGW, mostly propaganda, dogma, confirmation bias and hand waving. Climate change is going to be 4 C? When is that? The next interglacial?

        Both the ~60 year pseudo cycle and the longer ~200 year cycle seem to be plateauing – that means cooling. I say 30 years of no warming by ~2020.

      • Edim, that null hypothesis doesn’t take into account any papers on the subject of natural variability that show its presence in various oscillations and scale as seen in the weather records. The null hypothesis is only a starting point for people who don’t know anything about a subject, which I guess you claim to not.

      • They gave you quite a beating on the blackboard, webby:

        http://rankexploits.com/musings/2013/the-ippc-slide-figure-1-4/#comment-120004

        That’s gotta sting.

      • Don. it doesn’t phase him. Webster only considers “FAST” response. He is kinda Fast and Frivolous that way :)

      • DonDon,
        That doesn’t sting at all. I am dealing with a statistician that can do a lot of fancy footwork, PK, but lacks any degree of physical reasoning. All that stuff he did before is essentially down the dumper if he decides to include the SOI correction term.

        All they do at that place is set up strawman scenarios that they can beat back into submission. Give them some simple first order physical models and they freak out.

        Bring it on DonDon.

      • Actually webby, they cleaned your clock. You probably shouldn’t go back there again.

      • I know DonDon. They are accusing me of thread-jacking the play-time tea party they are enjoying amongst themselves.

        Oh my, have they got themselves a case of the vapors, hoping that if I go away that they won’t have to use the fainting couch.

      • I wonder why they don’t take you seriously, webby. Like we do here. Maybe you should have your own blog. Oh wait, nobody cared.

    • My concern echoes that of Pierrehumbert.

      http://www.slate.com/articles/health_and_science/science/2013/02/u_s_shale_oil_are_we_headed_to_a_new_era_of_oil_abundance.single.html

      Should engineers figure out how to bootstrap oil shale kerogen by using the energy stored in kerogen to extract it, the carbon emissions will go through the roof.

      This is such a marginally efficient process that the technology may end up wasting 1 unit of energy for every 1.1 unit extracted. That would mean that 10x of the CO2 would get emitted before it even gets used. And since the sequestering of the carbon may take even more energy, that step might get skipped. Kind of like mountain-top mining wouldn’t be efficient if you had to reconstruct the mountain-top that just got turned into rubble and tumbled down the slopes.

      The point is that these lower grades of fossil fuels are energy intensive, and the days of high EROEI sweet crude oil are long gone.
      Low EROEI guarantees more emissions even if supply stays constant.

    • A Lacis arrow to the string
      Bends a bow and looses Time.
      ========================

    • Jim Cripwell

      Andy is at it again. “All sound and fury, signifying nothing”. Climate models which have not, and cannot be validated, tell us absolutely nothing about what might happen to our climate in the future. We cannot measure the climate sensitivity of CO2, so no-one has any idea what it’s value is. Andy’s long, arrogant dissertation is just hand-waving, with no scientific validity.

      • Try learning some science instead of “just hand-waving, with no scientific validity”.

      • Steven Mosher

        Andy, you wont get anywhere with Jim.

      • David Springer

        A Lacis

        Physician, heal thyself.

      • I am fully aware of fundamentals of physics. I wish you answer one simple question. Has the climate sensitivity of CO2 been measured? A simple yes or no is all that is required.

      • Springer, A physician is different than a physicist.

        Diagnosis: Dolt

      • Mosh
        You can join Cripwell’s needlepoint club and perhaps learn from the master.

      • David Springer

        WebHubTelescope (@whut) | October 4, 2013 at 1:14 pm |

        “Springer, A physician is different than a physicist.”

        Physician, heal thyself is a proverb not a literal command you culturally illiterate buffoon. You know, like if I stated the plain fact that you parrot the warmist party line with no understanding of it I wouldn’t literally mean you ‘re a parrot. I would never insult a parrot like that.

        Write that down.

    • And here we have it courtesy of A Lacis, the alarmists mantra to be chanted 100 times before going to sleep

      “(1) it is increase in atmospheric CO2 (and the other minor non-condensing greenhouse gases) that control the greenhouse warming of the climate system; (2) water vapor and clouds are feedback effects that magnify the strength of the greenhouse effect due to the non-condensing greenhouse gases by about a factor of three”

      and repeat

      • THE SKY IS FALLING, THE SKY IS FALLING!

        OOPS! NOT YET!

        REPEAT!

      • David Springer

        Actually albedo is the feedback mechanism not water vapor. Ice is a positive feedback fostering more ice. Liquid ocean surface is a positive feedback fostering more surface warming. Clouds are a negative feedback which prevents a runaway greenhouse effect from more liquid ocean surface.

        The basic operating principles of climate are not rocket science. Getting exact numbers for time and magnitude especially in smaller regions is the wicked problem. I’ve never disagreed with the possibility of climate disruption from anthropenic activities I’ve only argued that disruption is very likely to be overshadowed by net benefits like modest warming when the earth has been in a ice age for 4 million years, more warming in the higher latitudes and less in the lower exactly where most people would wish for warming (or lack thereof), and fertilization of the atmosphere with CO2 (plant food). Severe weather should decrease as the delta T between tropics and poles decreases in an asymmetric warming. The disruption is likely to come from the desert belt growing wider even as the temparate zone expands and polar climate zone contracts. You have to break a few eggs to make an omelet. [shrug]

  48. Chief Hydrologist

    There is about 100 years of oil supply at current usage – much more gas and much, much more coal.

    Shale oil is about 10% of the oil reserve and shale gas is some 50% of the gas reserve.

    http://www.eia.gov/analysis/studies/worldshalegas/

    Never let the facts get in the way of a good story.

    BTW – the myth of Norway as a successful high spending, big government social democracy has just imploded.

    Scheduled for their viewing pleasure next month is 5 hours of knitting. This follows the hugely successful 12 hour TV marathon on how to build and start a wood fire watched by 95% of the country. Future programs include a six episode mini-series on how to season a skillet and a made for TV movie on dishwashing.

    If this is how they measure success – give me a dysfunctional government and Miley Cyrus.

    • Yes those Norwegians should be flying around in luxury cars, buying up huge houses, yachts and plasma TV sets. The real measure of “success”.

  49. If they dropped the too hot climate models from the ensembles then the ‘dangerous’ would really fly out of the window. Any thoughts why they don’t?

  50. Pingback: Did The IPCC AR5 Take The ‘Dangerous’ Out Of Global Warming? | The Global Warming Policy Foundation (GWPF)

  51. I am 95% certain this is 100% BS:

    In summary, it is indisputable that UHI [Urban Heat Island] and LULC [land-use land-cover change] are real influences on raw temperature measurements. At question is the extent to which they remain in the global products (as residual biases in broader regionally representative change estimates). Based primarily upon the range of urban minus rural adjusted dataset comparisons and the degree of agreement of these products with a broad range of reanalysis products, it is unlikely that any uncorrected urban heat-island effects and LULC change effects have raised the estimated centennial globally averaged LSAT trends by more than 10% of the reported trend (high confidence, based on robust evidence and high agreement). This is an average value; in some regions with rapid development, UHI and LULC change impacts on regional trends may be substantially larger. ~IPCC WGI Fifth Assessment Report

    • Steven Mosher

      Actually its accurate.

      1. UHI is real in raw data
      2. LULC is real in raw data
      3. based on studies of urban – Rural — with adjusted data the difference
      is less than 10%
      4. The adjusted data agrees with re analysis data ( same answer different sources ) Note Fall et al ( anthonys paper) used re analysis data
      5. Some regions ( like china and japan ) show more than 10%.

      That is just a pure summary of the science, published science.

      Now, somebody might publish a study that shows something different for GLOBAL numbers, but they havent done so.

      FWIW; for global raw Ive seen around 10%or more for the 1979-2010 time period.

    • I WOULD GO WITH 200% OR MORE!

      • Many know about the placing official thermometers at French airports where the runways are continually cleared of snow resulted in ostensibly higher winter temperatures compared to the surrounding countryside (the tarmac effect). Absent the tarmac effect there has been not global warming in France for 70 years.

        Interestingly counter-intuitive is the air conditioner effect in Paris on nighttime temperatures.

        ABSTRACT:

        A consequence of urban heat islands in summer is an increase in the use of air conditioning in urbanized areas, which while cooling the insides of buildings, releases waste heat to the atmosphere. A coupled model consisting of a meso-scale meteorological model (MESO-NH) and an urban energy balance model (TEB) has been used to simulate and quantify the potential impacts on street temperature of four air conditioning scenarios at the scale of Paris. The first case consists of simulating the current types of systems in the city and was based on inventories of dry and evaporative cooling towers and free cooling systems with the river Seine. The other three scenarios were chosen to test the impacts of likely trends in air conditioning equipment in the city: one for which all evaporative and free cooling systems were replaced by dry systems, and the other two designed on a future doubling of the overall air conditioning power but with different technologies. The comparison between the scenarios with heat releases in the street and the baseline case without air conditioning showed a systematic increase in the street air temperature, and this increase was greater at nighttime than day time. It is counter-intuitive because the heat releases are higher during the day. This is due to the shallower atmospheric boundary layer during the night. The increase in temperature was 0.5°C in the situation with current heat releases, 1°C with current releases converted to only sensible heat, and 2°C for the future doubling of air conditioning waste heat released to air. These results demonstrated to what extent the use of air conditioning could enhance street air temperatures at the scale of a city like Paris, and the importance of a spatialized approach for a reasoned planning for future deployment of air conditioning in the city.

        Cecile de Munck, et al., How much can air conditioning increase air temperatures for a city like Paris, France? Int. J. Climatol. 33. 210 – 227 (2013)

      • Waggie

        While the results are interesting, my antennae wiggled at the use of the term “waste heat”. WTF does that signify? It’s heat, period, as you Americans like to say. Perhaps it’s a subtlety lost in translation.

        I was also surprised to see you promoting an article that concluded that more planning of airconditioning in cities was a worthy objective. Still, results are results. Was that your point?

  52. Mosh

    for global raw Ive seen around 10%or more for the 1979-2010 time period.

    Comparing global (land only) surface (BEST & HadCRUT4) with UAH & RSS (land only), which have no UHI distortion, the satellite trend lines look about one-third lower (rather than 10%)

    http://www.woodfortrees.org/plot/best/from:1979/to:2010/trend/plot/crutem4vgl/from:1979/to:2010/trend/plot/rss-land/from:1979/to:2010/trend/plot/uah-land/from:1979/to:2010/trend

    BEST/CRU (land only) 0.86/31 = 0.277C per decade
    UAH/RSS (land only) 0.58/31 = 0.187C per decade

    0.187 is around 67% of 0.277

    Realize there is more to it than simply comparing surface with satellite trends.

    But there is also the problem that GH warming should actually be at a faster rate in the troposphere than at the surface (according to IPCC), and this clearly doesn’t seem to be the case.

    Max

  53. Pingback: Extreme events and catastrophes | The IPCC Report

  54. Irreversibility of ice sheets and level rise are also assessed in Chapter 13.

    Junk! Ice Core Data shows that when the ice melts, it always gets cold afterwards. IT SNOWS WHEN THE ICE IS MELTED AND THE WATER IS WARM. NOT WHEN THE WATER IS FROZEN.

    THEY HAVE NO UNDERSTANDING OF THE POLAR ICE CYCLE!

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