by Judith Curry
The U.S. House Subcommittee on Environment is holding a Hearing today: A Factual Look at the Relationship Between Climate and Weather.
From the opening statement by Committee Chair Lamar Alexander:
President Obama stated in his 2013 State of the Union Address that, “We can choose to believe that Superstorm Sandy, and the most severe drought in decades, and the worst wildfires some states have ever seen were all just a freak coincidence. Or we can choose to believe in the overwhelming judgment of science and act before it’s too late.”
However, the “overwhelming judgment of science” does not support the President’s claims.
According to the Intergovernmental Panel on Climate Change (IPCC), there is “high agreement” among leading experts that long-term trends in weather disasters are not due to human-caused climate change.
Instead of trying to scare the American people and promote a political agenda, the administration should try to protect the lives and property of our nation’s residents from extreme weather by better weather forecasting.
I hope this hearing will make clear that the impact of climate change is often exaggerated. Politicians and others should rely on good science, not science fiction, when they discuss extreme weather. Otherwise, they will lack credibility when advocating new policy changes.
Witnesses (click on name to link to written testimony):
- Dr. John R. Christy, Professor and Director, Earth System Science Center, NSSTC, University of Alabama in Huntsville
- Dr. David Titley, Director, Center for Solutions to Weather and Climate Risk, Pennsylvania State University
- Dr. Roger Pielke Jr., Professor and Director, Center for Science and Technology Policy Research, University of Colorado
John Christy
Summary statements from Christy’s testimony:
I see two things here, (1) the need to go back to the drawing board on climate modeling with special attention to the causes of natural variations and with a rigorously independent validation program, and (2) the world community needs to be exposed to the real debates in climate science rather than statements amounting to a consensus of those who already agree with a certain consensus.
I believe we missed a tremendous opportunity 17 years ago to develop a better understanding of the climate system because research dollars were directed to establish a climate modeling industry. To compound the problem as it developed, I believe we failed to fund substantial projects to examine the output of climate models in an independent, objective and methodological way. This has left us 17 years later still wondering what portion of the recent modest change is natural and what portion might be human-caused.
In this testimony, evidence is presented to demonstrate that recent weather events are not outside the extremes that have occurred in the past when human influences were negligible. Therefore in my view one cannot attribute these recent events with any confidence to something beyond nature. Climate models are promoted as tools that are able to discriminate natural climate events versus those that might happen as a result of the increases in greenhouse gases due to human activities and have been used by EPA for regulatory action. Unfortunately, as demonstrated here and discussed in the literature, climate models have not demonstrated acceptable skill in terms of depicting even very fundamental, large-scale climate variations, and thus are unable to identify natural versus human-influenced events on regional scales. Indeed, the lack of modeling skill regarding very basic processes such as tropical tropospheric variations, indicates that the modeling enterprise has not been subject to rigorous, independent “Red Team” oversight during its expensive growth period. In addition, significant advancements are needed in observing and understanding the natural processes of climate before reliable, though basic, forecasts are forthcoming. It is unfortunate, in my opinion, that recent policy has been made based on the projections of these faulty models. Climate science has a long way to go.
I find Christy’s testimony to be very effective and I don’t disagree with anything he says here. I note that at the end of his testimony, he appends my essay IPCC diagnosis – permanent paradigm paralysis. If you missed it the first time, take a look. Apparently Christy really liked this essay; he asked if he could include it in his testimony. I note that I prepared that essay as part of written testimony for a Senate hearing that was cancelled.
David Titley
Titley’s testimony starts with a summary of IPCC findings, general findings about warming. Some excerpts from the latter part of the talk:
What does all this mean? The absence of evidence is not the evidence of absence. Or stated another way, saying we don’t know today the impact of climate change on these phenomena is very different than stating that climate change has no impact on typhoons and hurricanes. What we do know is that these storms are forming in a warmer, moister environment and above a warmer ocean. We also know that current research indicates our future may include more intense, and possibly more frequent, storms. That is a risk not to be summarily discounted.
I am frequently asked if a specific or extreme event (for example, typhoon, Sandy, drought, snowstorm) is or is not “caused” by climate change. Frankly, that is the wrong question. It’s like asking someone if their childhood upbringing “caused” him or her to attend a specific college. It’s more useful to think of climate as the deck of cards from which our daily, specific weather events are dealt. And as the climate changes, so does our deck of cards. For every degree of warming, we add an extra Ace into the deck. So, over time, the unusual hands, like a Full House with Aces high, become more plausible – and more common – with time.
A useful way to think about how to deal with this uncertain, but not completely unknown, future is through a risk management framework. Rather than wait for a series of extreme, or disruptive, events to occur and then react, an alternate way to approach our changing climate may be to adopt some proven tenets from the security community.
As we work on adapting to our changing climate we should not lose sight of the big picture: how to move the world’s energy system to a predominantly non-carbon based energy source to power the world. How can we unleash the innovation and energy that makes our country great to solve one of the grand challenges of the 21st Century? We are the country that is developing a self-driving car and whose private companies can send satellites to geosynchronous orbit. With the right policies I am sure our private sector can develop – and profit from – energy solutions that will power the world in a sustainable fashion into the future.
I don’t find Titley’s testimony to be effective. He didn’t sell hard the AGW-extreme weather link, rather his main argument was ‘absence of evidence is not evidence of absence’. With his deck of cards analogy, he discounts the possibility of AGW removing an Ace from the deck. He then brings in a risk management approach, and his final recommendation seems to be moving away from carbon energy sources. IMO, none of these seems effectively targeted (either logically or policy wise) at the issue of the relationship between climate change and extreme weather.’
Roger Pielke Jr
Take-home points from Pielke’s testimony:
There exists exceedingly little scientific support for claims found in the media and political debate that hurricanes, tornadoes, floods and drought have increased in frequency or intensity on climate timescales either in the United States or globally.
Similarly, on climate timescales it is incorrect to link the increasing costs of disasters with the emission of greenhouse gases.
Here are some specific conclusions, with further details provided below:
Globally, weather-related losses ($) have not increased since 1990 as a proportion of GDP (they have actually decreased by about 25%) and insured catastrophe losses have not increased as a proportion of GDP since 1960.
Hurricane landfalls have not increased in the US in frequency, intensity or normalized damage since at least 1900. The same holds for tropical cyclones globally since at least 1970 (when data allows for a global perspective).
Floods have not increased in the US in frequency or intensity since at least 1950. Flood losses as a percentage of US GDP have dropped by about 75% since 1940.
Tornadoes in the US have not increased in frequency, intensity or normalized damage since 1950, and there is some evidence to suggest that they have actually declined.
Drought has “for the most part, become shorter, less frequent, and cover a smaller portion of the U. S. over the last century.” Globally, “there has been little change in drought over the past 60 years.”
The absolute costs of disasters will increase significantly in coming years due to greater wealth and populations in locations exposed to extremes. Consequent, disasters will continue to be an important focus of policy, irrespective of the exact future course of climate change.
To avoid any confusion
Because the climate issue is so deeply politicized, it is necessary to include several statements beyond those reported above.
Humans influence the climate system in profound ways, including through the emission of carbon dioxide via the combustion of fossil fuels.
Researchers have detected and (in some cases) attributed a human influence in other measures of climate extremes beyond those discussed in this testimony, including surface temperatures (heat waves) and in some measures of precipitation.
The inability to detect and attribute increasing trends in the incidence of hurricanes, floods, tornadoes and drought does not mean that human-caused climate change is not real or of concern.
It does mean however that some activists, politicians, journalists, corporate and government agency representatives and even scientists who should know better have made claims that are unsupportable based on evidence and research.
Such claims could undermine the credibility of arguments for action on climate change, and to the extent that such false claims confuse those who make decisions related to extreme events, they could lead to poor decision making.
A considerable body of research projects that various extremes may become more frequent and/or intense in the future as a direct consequence of the human emission of carbon dioxide.
Our research, and that of others, suggests that assuming that these projections are accurate, it will be many decades, perhaps longer, before the signal of human-caused climate change can be detected in the statistics of hurricanes (and to the extent that statistical properties are similar, in floods, tornadoes, drought).
This testimony is vintage RP Jr, who is quite experienced and effective in providing Congressional testimony on this topic. I don’t disagree with anything Pielke Jr says in this testimony, and I find it to be effective testimony.
JC comments:
All three witnesses are veterans at providing Congressional testimony. On this particular topic, I don’t think that Titley was very effective. While the Democrats had only one ‘slot’ in this hearing, Titley may not have been the best choice for this hearing. I note that most U.S. climate/atmospheric scientists are in San Francisco this week, attending the AGU meeting, which might have reduced the population of available witnesses.
The bottom line is that variability in extreme weather events depends largely on natural internal variability. Identifying any sort of signal from AGW is exceedingly difficult (this point was made well by Christy). Attempting to reduce the damages associated with extreme weather in the 21st century by reducing greenhouse gas emissions is very misguided IMO, and misses important opportunities to focus on better weather forecasting, better emergency management practices, and reducing infrastructure vulnerability.