My testimony has four objectives:
1) Demonstration that the rate greenhouse‐related warming is clearly below the mean of climate forecasts from the United Nations Intergovernmental Panel on Climate Change (IPCC) that are based upon changes in atmospheric carbon dioxide concentrations that are closest to what is actually being observed,
2) demonstration that the Finding of Endangerment from greenhouse gases by the Environmental Protection Agency is based upon a very dubious and critical assumption,
3) demonstration that the definition of science as a public good induces certain biases that substantially devalue efforts to synthesize science, such as those undertaken by the IPCC and the U.S. Climate Change Science Program (CCSP), and
4) demonstration that there is substantial discontent with governmental and intergovernmental syntheses of climate change and with policies passed by this House of Representatives.
“Climate change” is nothing new, even climate change induced by human activity. What matters is not whether or not something so obvious exists, but to what magnitude it exists and how people adapt to such change.
For decades, scientists have attempted to model the behavior of our atmosphere as carbon dioxide and other greenhouse gases are added above the base levels established before human prehistory. The results are interesting but are highly dependent upon the amount of carbon dioxide that resides in the atmosphere, something that is very difficult to predict long into the future with any confidence. It is safe to say that no one — no matter whether he or she works for the government, for industry, or in education — can tell what our technology will be 100 years from now. We can only say that if history is to be any guide, it will be radically different from what we use today and that therefore projecting greenhouse gas emissions so far into the future is, to choose a word carefully, useless.
One thing we are certain of, though, is that the development of future technologies depends upon capital investment, and that it would be foolish to continue to spend such resources in expensive programs that will in fact do nothing significant to global temperature.
Fortunately, despite the doomsaying of several, we indeed have the opportunity to not waste resources now, but instead to invest them much further in the future. That is because the atmosphere is clearly declaring that the response to changes in carbon dioxide is much more modest that what appears to be the consensus of scientific models.
Testimony Objective #1: Greenhouse‐related warming is clearly below the mean of relevant climate forecasts from the IPCC
Figure 1 shows the community of computer model projections from the IPCC’s “midrange” scenario. Observed changes in atmospheric carbon dioxide concentrations correspond closer to this one than to others. You will note one common characteristic of these models: they predict warmings of a relatively constant rate. This is because, in large part, the response of temperature to changes in atmospheric carbon dioxide is logarithmic (meaning that equal incremental increases produce proportionally less warming as concentration increases), while the increase in carbon dioxide itself is a low‐order exponent rather than a straight line. This combination tends to produce constant rates of warming.
The various models just produce different quasi‐constant rates. Divining future warming then becomes rather easy. Do we have a constant rate of warming? And if so, then we know the future rate, unless the functional form of all of these models is wrong. And if this is wrong, scientists are so ignorant of this problem, that you are wasting your time in soliciting our expertise.
How does the observed rate of global temperature increase compare to what is being projected? For that, we can examine the behavior of literally hundreds of iterations of these models. For time periods of various lengths, some of these models will actually produce no significant warming trend (as has been observed since 1996), or even a short‐term interval of cooling.
Figure 2 gives us the mean and 95% confidence limits of the midrange family of IPCC models as well as temperatures observed by the Climate Research Unit at the University of East Anglia. (More will be said on this history below). It is quite apparent that the observed rates of change are below the mean value forecast by the IPCC.
An additional and important discrepancy between the models and reality extends into the lower atmosphere as well. In the lower atmosphere, climate models expectations are that the degree of warming with increasing greenhouse gas concentrations should be greater than that experienced at the surface, with the lower atmosphere warming about 1.4 times faster than the average surface temperature. Despite claims that observations and models are in agreement (Santer et al., 2008), new analyses incorporating a large number of both observational datasets as well as climate model projections, clearly and strongly demonstrate that the surface warming (which itself is below the model mean) is significantly outpacing the warming in the lower atmosphere — contrary to climate model expectations. Instead of exhibiting 40% more warming than the surface, the lower atmosphere is warming 25% less — a statistically significant difference (Christy et al., 2010).
And further, the climate models are faring little better with oceanic temperature changes. There again, they project far more warming than has been observed. In a much‐publicized paper published in Nature magazine in 2006 (by authors Gleckler, Wigley, Santer, Gregory, AchutaRao, Taylor, 2006), it was claimed that by including the cooling influence of a string of large volcanic eruptions starting in 1880, that climate models produced a much closer match to observed trends in ocean warming than when the models did not include the volcanic impacts. Further, it was claimed that volcanic eruptions as far back as Krakatoa in 1883 were still significantly offsetting warming from human greenhouse gas emissions. However, a soon‐to‐be‐published paper by one of the Nature paper’s original authors, Jonathan Gregory, shows that the influence of volcanoes was greatly exaggerated as the original climate models assumed that no major volcanic eruptions had occurred prior to Krakatoa. In fact, episodic major eruptions are an integral part of the earth’s natural climate. Gregory shows that had climate models been equilibrated with more realistic natural conditions, that the long‐term impact of volcanoes since the late 19th century would be greatly minimized. In that case, the apparent match between model simulations and observations of oceanic heat content that was noted by Gleckler et al. would deteriorate, leaving climate models once again over‐responsive to rising levels of greenhouse gases.
I caution you that analyses of climate models can be highly dependent upon the time period chosen. There was a major El Nino event in 1998, which is the warmest year in the instrumental histories. Thus any analysis beginning in this year will show little warming. On the other hand, if one studies the last twenty years, there is a major volcano at the beginning of the record (Pinatubo in 1991), so any analysis beginning then will show anomalously large warming trends.
An example of the time dependency of model validation can be seen in one of the most famous papers ever published on this subject, by Santer et al. (1996). It was clearly rushed to print by Nature magazine in order to provide a scientific justification for the Second Conference of the Parties to the United Nations Framework Convention on Climate Change, held in Geneva a mere few days after its publication. The findings were reported in virtually every major newspaper on the planet in this politically sensitive timeframe.
The analysis shows a remarkable fit between the observed three‐dimensional changes in the atmosphere and what was projected by models between 1963 and 1987. But, indeed, this three‐dimensional history actually begins in 1957, and, for the purposes of this paper, clearly ends in 1995, not 1987.
The major match for this record results from the substantial warming of the southern hemisphere compared to the northern (Figure 3). Indeed the time evolution of southern hot spot is striking from 1963 through 1987. But, when all of the data are used, the warming trend completely disappears.1
Nonetheless, the Geneva conference marked the turning point in international climate change policy. It was agreed there that at the next conference, in Kyoto, that the nations of the world would adopt a binding protocol to reduce carbon dioxide emissions. The resultant Kyoto protocol demonstrably did nothing about climate change and was an historic, expensive failure that led to the ultimate failure in subsequent policy that took place in Copenhagen last December.
Testimony Objective #2: The Finding of Endangerment from greenhouse gases by the Environmental Protection Agency is based upon a very dubious and critical assumption
The reluctance of the Senate to mandate significant reductions in carbon dioxide emissions has resulted in EPA taking the lead in this activity. Consequently it issued an “endangerment finding” on December 7, 2009. The key statement in this Finding is adapted from the Fourth Assessment Report of the IPCC and from the CCSP: