In 2007, a divided Supreme Court ruled that the Environmental Protection Agency must treat carbon dioxide and other greenhouse gases as "pollutants," and must therefore analyze whether the increasing concentrations in atmospheric carbon might reasonably be anticipated to endanger human health and welfare. The court may be on the verge of facing this issue once again.
To be clear, the court did not mandate regulation in 2007; rather, it mandated that the EPA go through what is known as an "Endangerment Finding" process. The EPA did so and on Dec. 15, 2009, issued its ruling that carbon dioxide and other greenhouse gases must be regulated. This EPA finding and associated rulings were immediately challenged in the federal D.C. Circuit Court, which initially ruled in favor of the EPA.
Given the two dissenting judges in the circuit's en banc decision just before Christmas, the matter will very likely go to the Supreme Court.
If allowed to stand, the very existence of the EPA's Endangerment Finding requires regulation that would significantly increase U.S. fossil fuel and electricity prices -- negatively affecting job creation as well as energy, economic and national security.
To many scientists, this situation seems incredible, given the ample evidence that the EPA's finding is flawed. In its finding, the EPA claimed with 90 to 99 percent certainty that observed warming in the latter half of the 20th century resulted from human activity. The EPA bases its finding upon three "lines of evidence," none of which hews to the most credible empirical data available.
First, the EPA claims that the global average surface temperature has been rising in a dangerous fashion over the last 50 years, in large part due to human-caused increases in atmospheric carbon dioxide concentrations. But "global warming" has not been global, nor has it even set records in the regions where warming has occurred. For example, over this time period, while the Arctic has warmed, the tropical oceans had a flat trend, and the Antarctic was cooling. The most significant warming during this period occurred in the Northern Hemisphere, north of the tropics. But over the last 130 years, the 1930s still has the most U.S. state high temperature records. Over the past 50 years, there were more new state record lows set than record highs. In fact, roughly 70 percent of the current state record highs were set before 1940.
Second, the EPA argues that in the tropics, the upper troposphere is warming faster than the lower troposphere, and the lower troposphere is warming faster than the surface, all due to rising carbon concentrations. This is totally at odds with multiple robust, consistent, independently derived empirical data sets, all showing no statistically significant positive (or negative) trend in temperature, and thus no difference in trend by altitude.
Third, the EPA relied upon climate models predicated on this theory. All of these models fail standard model validation and forecast reliability tests. The models all forecast rising temperatures beyond 2000, although the global average surface temperature has actually been flat. This is not surprising because the EPA never carried out any published forecast reliability tests.
The bottom line is that no scientist or team of scientists has come up with an empirically validated theory proving what the EPA claims it knows with 90 to 99 percent certainty. Moreover, if the EPA's three lines of evidence are so easily refuted, then the EPA's strong claim of causality, that higher carbon emissions affect sea levels and severe storm, flood and drought frequency, is on ever shakier ground. This is an inevitable problem when a person or agency tries to prove too much.
Joseph S. D'Aleo, a certified consulting meteorologist, is a fellow of the American Meteorological Society.