Three scientists walk into a hearing room ...
Seriously. Yesterday I was on Capitol Hill talking about global warming with Richard Muller of the Berkeley Earth Surface Temperature (BEST) project and Ben Santer of the Lawrence Livermore National Lab. The Congressional briefing was organized by Congressmen Ed Markey (D-MA) and Henry Waxman (D-CA), who authored the American Clean Energy and Security Act which passed the House in June 2009 and would have set up a carbon market to address climate change had the Senate followed suit. (A quick note: this was a briefing, not a hearing, because the organizers, being in the minority party, cannot unilaterally convene a hearing, which, presumably in this case, the majority party wanted no part of.)
Given the deadlock in D.C. and a keen sense that the legislative body seems hell-bent on dismantling policies to address climate change rather than addressing the problem, I'm not sure why the briefing was held. Perhaps it was part of a tactical retreat designed to slow the invading denier-army -- taking advantage of the release of the BEST results to put some of the latest climate stuff on the record -- and to maybe show the international community we're still relevant in advance of the upcoming climate talks in Durban.
At any rate, here's a brief synopsis of what was said.
In their opening remarks Markey and Waxman both railed against their anti-science, obstructionist colleagues who not only refuse to consider climate legislation but continue to deny the science. Then we scientists spoke.
Richard Muller focused on the results of his recent, well-publicized BEST study: namely, that the skeptics' claims of bias in previous analyses of global surface temperature are unfounded.
Through an independent analysis of data from 39,000 temperature stations, the BEST project reproduced previously derived temperature trends even after accounting for potential biases due to:
Their conclusion [pdf]? Over the past 50 years land-surface temperatures have increased by about 1.8 degrees Fahrenheit, essentially the same increase calculated by NASA's Goddard Institute for Space Studies (GISS), NOAA's National Climatic Data Center (NCDC), and the UK Met Office Hadley Center and the University of East Anglia's Climatic Research Unit (HadCRU), and reported by the IPCC.
There's little doubt that much of the hubbub over the BEST project arises from Muller's identification as a "skeptic" and the study's partial funding by the right-leaning Koch Foundation. In person Muller portrayed a more ambivalent view about skepticism and his status as a card-carrying skeptic, referring to himself as someone "considered a skeptic by the skeptics." Averring that there's a difference between skeptics (good) and deniers (bad), he identifies as a skeptic on climate science since all scientists are skeptics. Or, more accurately, he was a global-warming skeptic until his own study confirmed what others had found before him.
I have to say the philosophical, what-is-a-skeptic discussion rankled. He seemed to imply that all scientists should have been skeptics like him before his study, and that he's the only one to have taken skeptics' criticisms seriously and actually investigated their claims. In fact Muller was not the first to assess the potential biases to the temperature record (see for example here, here [pdf], here and here). But like previous investigators into such issues raised by skeptics, Muller found the phenomena to be non-issues. Did those other scientists violate some sacred principle of scientific skepticism by accepting their own exhaustive studies' results without having waited for Muller to come along with his study? Certainly not.
Nevertheless, Muller's contribution adds a welcome and independent piece of evidence on global warming, evidence that has been accumulating over many decades of scientific study. It's also probably what got us to DC.
Ben Santer has spent much of his scientific career working on climate change attribution -- trying to identify what causes or drives climate change in general and what has caused the last 50 years or so of the global warming in particular. His presentation was a tour de force.
Santer described how he et al use a combination of global climate data and climate model simulations to "tease out the effects of natural and human influences" on climate change. They do this by looking for telltale patterns, or "fingerprints," within the spatial and temporal variation of the simulations to identify what's behind the change.
For example, of all the potential drivers of global warming, greenhouse gases, because they trap heat in the lower atmosphere, uniquely cause the lower atmosphere to warm and the upper atmosphere to cool -- this is the greenhouse gas fingerprint. Warming due to an uptick in solar output, by contrast, leads to warming of the entire atmospheric column. As it turns out, the lower atmosphere has warmed and the upper atmosphere has cooled. Ergo, Santer argues, solar forcing cannot be a major factor in the current warming. Similarly, concurrent patterns of warming in all the major ocean basins of the world as well as the atmosphere would seem to eliminate the ocean as the driver of warming.
It was these types of studies that led the second report of the Intergovernmental Panel on Climate Change to conclude "the balance of evidence suggests that there is a discernible human influence on global climate," and the subsequent IPCC report to conclude that "most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations."
As the leading author of the second report's eighth chapter, which first used "discernible" to describe human contributions, Santer said that he'd taken a good deal of heat from some who claimed the statement was politically motivated and not scientifically grounded. He clearly feels vindicated by the body of evidence that has grown in the intervening years that backs up that original statement and, if anything, suggests it was not definitive enough.
I appeared at the hearing in my capacity as the vice chair of the Committee on America's Climate Choices and as such focused my remarks on the committee's findings. (You can read my remarks here [pdf]. Added 11/17/2011.))
During the Q&A session that followed the presentations, talk turned to the role of humans in global warming, and it became pretty clear that Muller remains a skeptic on that front. Here again I was somewhat rankled when he brought forth red herrings like sunspots even though data clearly show that they cannot have been the cause. This time the rankling got the better of me and I challenged his red herrings, perhaps sounding a short, discordant note in the scientific trio.
I'm skeptical that the briefing lived up to its name -- "An End of Climate Change Skepticism" -- but I'd have to say in the end the event was rather anticlimactic. Perhaps the writing was on the wall from the outset. As we filed into the Longworth House Office Building, we entered a meeting room that looks like what you've seen on TV -- seats for members of Congress arranged in a U-shape around the elevated dais, the lowly speakers' table facing our representatives, and behind us ample seating for the 40 or so attendees who watched, including legislative aides, people from non-governmental organizations, and members of the media with cameras a-flashing.
Yes, all the trappings of a high-powered Congressional event with one glaring exception: Seated in the 25 or so chairs along the dais dedicated for our esteemed leaders in Congress were just two representatives, Waxman and Markey. I wouldn't hold my breath waiting for a Congressional resolution marking the end of climate skepticism -- or the beginning of major climate legislation -- any time soon.
Crossposted with TheGreenGrok.com.
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