by Judith Curry
Some interesting follow-up questions from the House Committee on Science, Space and Technology regarding my recent Congressional testimony.
For reference, my previous blog post on the Hearing, along with my testimony, can be found [here].
I received questions from two Members (both Republicans). The questions and my draft responses are provided below.
1. President Obama has warned that, “for the sake of our children and our future, we must do more to combat climate change.” He said we must “choose to believe in the overwhelming judgment of science – and act before it is too late.”
A. Is there an overwhelming judgment of science or any science, showing that the President’s regulatory actions will prevent the threat that he is so concerned about?
If you believe the climate models, then President Obama’s INDC commitment (total of 80% emissions reduction by 2015), then warming would be reduced by 0.11 degrees Centigrade, a number that was provided to me by Chip Knappenberger of CATO using the MAGICC model with an equilibrium climate sensitivity of 3.0oC http://www.cato.org/blog/002degc-temperature-rise-averted-vital-number-missing-epas-numbers-fact-sheet. If the climate models are indeed running too hot, then the warming would be reduced by an even smaller number.
2. We have heard a lot of doomsday scenarios about what will happen if we do nothing on climate change. However, there has been less attention to what the results of any actions we take to combat climate might be.
A. Suppose we cut all greenhouse gas emissions in the United States. Would this avert the supposed catastrophic impacts?
Eliminating all U.S. greenhouse gas emissions by 2050 would reduce the warming by 0.014oC (as per the EPA MAGICC model). This is an amount of warming that is much smaller than the uncertainty in even measuring the global average temperature.
3. Dr. Curry, what happens to academics who step out of line on climate change?
A. Why would experts be afraid to question climate change orthodoxy?
The censure of scientists disagreeing with the IPCC consensus was particularly acute during the period 2005-2010. As revealed by the Climategate emails, there was a cadre of leading climate scientists that were working to sabotage the reviews of skeptical research papers (and presumably proposals for research funding). Further, scientists challenging climate change orthodoxy are subjected to vitriolic treatment in news articles, op-eds and blogs, damaging the public reputation of these scientists. I have heard from numerous scientists who are sympathetic to my efforts in challenging climate change orthodoxy, but are afraid to speak out or even publish skeptical research since they are fearful of losing their job.
Since 2010, things have improved somewhat especially in Europe; I think this has largely been due to reflections following Climategate and the fact that disagreement about climate change is not as starkly divided along the lines of political parties (i.e. the issue is somewhat less politicized). In the U.S., with President Obama’s recent pronouncements about climate denial and climate deniers (as anyone who does not agree with the consensus) has increased the toxicity of the environment (both academic and public) for scientists that question the IPCC consensus on climate change.
4. Dr Curry, have climate models been in the same as actual, observed temperatures?
A. Does the failure of climate models matter?
B. Have the U.S. climate models ever been run with lower sensitivity? If so, have these results been archived for public access?
Particularly for the past decade, climate models have been running too hot, predicting more warming than has been observed (refer to the figure on page 6 of my testimony http://www.climate-lab-book.ac.uk/comparing-cmip5-observations/.
The discrepancies between observed surface temperatures and climate model simulations indicates that climate models are not useful for predicting climate on decadal time scales (out to 20 years) or for regional spatial scales. If the so-called warming hiatus continues for another few years, then the observations will be completely outside of the envelope of climate model predictions.
I have argued that climate models are not fit for the purpose of simulating decadal scale and regional climate variability. Climate models are mainly useful for scientific exploration of mechanisms in the climate system. Whether they are at all useful for projections of century scale climate change remains to be seen, but I am doubtful.
For the main climate models used in the CMIP5 simulations for the IPCC AR5, climate sensitivity is an emergent property and not one that is easily tuned. For simpler climate models, such as MAGICC http://www.cgd.ucar.edu/cas/wigley/magicc/, climate sensitivity can be tuned, see http://www.cato.org/blog/002degc-temperature-rise-averted-vital-number-missing-epas-numbers-fact-sheet
5. The input to the models is the aggregate emissions, not the annual emissions. Do you have any estimate of the aggregate emissions of China, India, and Russia between 2005 and 2030?
A. How does this compare to the aggregate emissions REDUCTIONS claimed by the Obama Administration for the U.S.?
This is sufficiently outside of my expertise that I am respectfully declining to answer this question.
6. Dr. Curry, you mention uncertainty and the importance of understanding natural climate variability better before inferring sensitivity to greenhouse gases.
A. What are the current key gaps in our understanding of natural climate variability?
- Solar impacts on climate (including indirect effects). What are the magnitudes and nature of the range of physical mechanisms?
- Nature and mechanisms of multi-decadal and century scale natural internal variability. How do these modes of internal variability interact with external forcing, and to what extent are these modes separable from externally forced climate change?
- Deep ocean heat content variations and mechanisms of vertical heat transfer between the surface and deep ocean.
- The strength of carbon cycle feedbacks (both land and ocean)
- Climate dynamics of clouds: Could changes in cloud distribution or optical properties contribute to the global surface temperature hiatus? How do cloud patterns (and TOA and surface radiative fluxes) change with shifts in in atmospheric circulation and teleconnection regimes (e.g. AO, NAO, PDO)? How do feedbacks between clouds, surface temperature, and atmospheric thermodynamics/circulations interact with global warming and the atmospheric circulation and teleconnection regimes?
B. What are the most glaring or problematic uncertainties, ambiguities and areas of ignorance at this state in our understanding of climate change?
There are two overarching issues:
- Whether the warming since 1950 has been dominated by human causes
- How much the planet will warm in the 21st century
In addition to the points in A above I would add:
- Sensitivity of the climate system to external forcing, including fast thermodynamic feedbacks (water vapor, clouds, lapse rate).
C. What might happen if we miscalculate the atmosphere’s sensitivity to greenhouse gases and incorporate this miscalculation into global policies and strategies that are not flexible and adaptive?
We risk damaging our economy and current energy infrastructure
D. Would you characterize any of the policies discussed in the U.S., such as major industrial CO2 restrictions, as flexible and adaptive?
Among flexible and adaptive policy responses, I would include the following:
- Energy conservation and efficiency measures
- Elimination of methane leaks
- Management of air pollution issues (ozone, small particulates)
- Reducing vulnerability to extreme weather events
7. In October 2014, you co-authored a paper that discussed climate sensitivity. Climate sensitivity is a simple metric for estimating how much warming should occur from a doubling of CO2. The IPCC has bounced around in the last 3 reports, being unwilling to provide a “best estimate” in the latest report.
A. How important is it to understand how sensitive the climate is to changes in greenhouse gases like CO2 (climate sensitivity) to determine actual impacts from the “national commitments” made by the Obama Administration and other governments?
Climate sensitivity is a direct input into the EPA MAGICC model, and into impact assessment models used to calculate the social cost of carbon. Therefore, climate sensitivity is a key input into policy making.
B. How well do we understand or “know” what the climate sensitivity is? What does the IPCC think the best estimate of climate sensitivity is?
Since the IPCC AR4 in 2007, both the upper bound (at the very likely level) and lower bound (at the likely level) to climate sensitivity have been lowered. There is a dichotomy between climate model estimates (higher) and observation based estimates (lower).
C. What do actual observations (vs. models) suggest about climate sensitivity?
The most recent estimates from observations suggest a transient climate response of 1.05 to 1.45 oC and equilibrium climate sensitivity of 1.2 to 1.8 oC [17-83% range] http://judithcurry.com/2015/03/19/implications-of-lower-aerosol-forcing-for-climate-sensitivity/
8. In the next 50 years (or 100 years), how much projected climate warming is expected to be the result of humans and how much is expected to be due to various natural causes?
The IPCC does not even attempt to project future climate change from the various natural causes.
A. What is our confidence level in these estimates?
Under the Business As Usual Emissions Scenario (RCP8.5), the IPCC AR5 projects a likely increase of global mean surface temperatures for 2081–2100 relative to 1986–2005 to be 2.6°C to 4.8°C (RCP8.5). The likely confidence implies that there is a 34% chance that the increase could lie outside this range. Personally, I think the IPCC is overconfident in their estimate; I would expect the warming to lie below this range.
B. When we hear projections of climate impacts, how much of these can we avoid with modest actions, and how much of this is basically unavoidable?
C. Can we stop hurricanes, tornadoes, earthquakes – “mother nature” with the actions that the president is promising?
Extreme weather and climate events have always occurred and will continue to occur. Further, sea level has been rising since the last ice age. Even if you believe the climate models and the IPCC assessment and we are successful at eliminating CO2 emissions, we would not expect to notice any significant difference in extreme events at the end of the 21st century. Measures to reduce our vulnerability to weather and climate extremes make sense whether or not humans are influencing climate in any significant way.
9. Are the current global temperatures running above or below that has been predicted by computer models? Why?
For the past decade, global surface temperatures have been running cooler than the model projections. The lack of recent warming appears to be caused by changes in ocean circulations in the Pacific and Atlantic Oceans, with perhaps some contribution from the sun.
10. Setting aside the uncertainties surrounding the science of climate change, some have argued that climate mitigation policies are like an insurance policy. Some claim that this “climate insurance policy” would protect us from the most severe consequences of climate change.
If we are to view climate mitigation policies as an insurance policy, the cost of the policy needs to be commensurate with the possible damage, and the policy has to actually be effective at shielding the policy holder from losses.
A. Would taking these emission reduction steps, like those outlined in the President’s INDC, actually mitigate the potentially severe impacts activists are pointing to?
The President’s INDC is not a good insurance policy, as per the above criteria.
B. When people talk about potential economic consequences of inaction of delayed action, are they only counting what the actions they are advocating would prevent? Or is there some fuzzy math going on here?
The concern about inaction comes from concern about passing the 2oC ‘danger’ threshold, possibly by mid-century. This concern relies on a very weak assessment that 2oC of warming is actually ‘dangerous’ and that we can believe the climate models (which seem to be running too hot).
1. In the past decade, and more predominantly in the past eight years, the federal government has spent a great deal of financial resources chasing the idea that humans are the primary cause of climate change and global warming.
2. Are there other areas of federally supported critical scientific research and development that have suffered of fallen behind due to the heightened focus on climate change?
I will restrict my comments to funding allocation WITHIN the field of climate change. Too much funding is being allocated to climate modeling and climate impact assessments, and not enough funding for observing systems and understanding natural variability – in particular the sun and ocean circulations.
3. Have we seen improvements in environmental factors related to climate change in the past several decades? For example, have we seen growth or resurgence in tropical rainforests or growth of ice caps and glacial areas?
Satellite observations show that the planet has been getting greener for the past two decades, in terms of vegetation growth. This is attributed to an increase in CO2 and also a generally warmer, wetter climate http://visibleearth.nasa.gov/view.php?id=1804
4. Is there potentially a negative impact of overbearing environmental regulations? For example, would higher energy prices force more Americans to use their fireplaces as a source of heat, which might product more CO2 per household than the ratio generated by power plants?
Energy regulations that push premature implementation of technologies (e.g. wind and solar) risk diverting resources away from genuine energy technology innovation. Energy regulations that raise energy prices will be a disproportionate burden to the poor. I have heard anecdotal evidence in the UK of people burning more wood to avoid high energy costs.
JC note: I invariably find these questions to be very interesting, provides significant insight into what the Congressional Representatives find important. Please keep your comments relevant to these questions, I hope to obtain some useful feedback from your comments.