In his Aug. 6 op-ed, "A New Climate-Change Consensus," Environmental Defense Fund President Fred Krupp speaks of "the trend—a decades-long march toward hotter and wilder weather." We have seen quite a few such claims this summer season, and Mr. Krupp insists that we accept them as "true." Only with Lewis Carroll's famous definition of truth, "What I tell you three times is true," is this the case.
But repetition of a fib does not make it true. As one of many pieces of evidence that our climate is doing what it always does, consider the National Oceanic and Atmospheric Administration's year-by-year data for wet and dry years in the continental U.S.
From 1900 to the present, there are only irregular, chaotic variations from year to year, but no change in the trend or in the frequency of dry years or wet years. Sometimes there are clusters of dry years, the most significant being the dry Dust Bowl years of the 1930s. These tend to be followed by clusters of wet years.
Despite shrill claims of new record highs, when we look at record highs for temperature measurement stations that have existed long enough to have a meaningful history, there is no trend in the number of extreme high temperatures, neither regionally nor continentally. We do see the Dust Bowl years of the 1930s setting the largest number of record highs, at a time when it is acknowledged that humans had negligible effect on climate.
What about strong tornadoes? Again there is no trend. Last year was an unusually active season, and unfortunately some of those storms ravaged population centers. We were told that these disasters were the result of human CO2 emissions. Yet 2011 was only the sixth worst for strong tornadoes since 1950 and far from a record. And have any of us heard about this tornado year? Why not? Because 2012 has been unusually quiet. Most of the tornado season is behind us, and so far the tornado count is mired in the lowest quintile of historical activity. As for hurricanes, again there is no discernible trend. Regarding wildfires, past western fires burned far more acreage than today. Any climate effect on wildfires is complicated by the controversial fire suppression practices of the past hundred years.
Lurid media reporting and advocates' claims aside, even the last comprehensive Intergovernmental Panel on Climate Change report noted that "archived data sets are not yet sufficient for determining long-term trends in [weather] extremes." Yet this has not stopped global warming advocates from using hot summer weather as a tool to dramatize a supposedly impending climate Armageddon.
In a telling 2007 PBS interview, former Sen. Tim Wirth gloated about how he had rigged the 1988 Senate testimony chamber to dramatize the impact of NASA scientist James Hansen's histrionic testimony on imminent danger from global warming: "We called the Weather Bureau and found out what historically was the hottest day of the summer . . . So we scheduled the hearing that day, and bingo, it was the hottest day on record in Washington or close to it."
Not content to gamble on the vagaries of weather statistics, Mr. Wirth also boasted, "What we did is that we went in the night beforehand and opened all the windows . . . so the air conditioning wasn't working inside the room . . . when the hearing occurred, there was not only bliss, which is television cameras and double figures, but it was really hot." Tricks like those described by Sen. Wirth have been refined to an art to promote the cause of economically costly action to prevent supposedly catastrophic consequences of increasing CO2. Contrast these manipulations with the measured and informative Senate testimony of climatologist John Christy earlier this month.
In an effort to move the science debate completely into the political arena, Mr. Krupp implies that with the exception of a few enlightened Republican governors and captains of industry, most "conservatives" are climate skeptics—and vice versa. But some of the most formidable opponents of climate hysteria include the politically liberal physics Nobel laureate, Ivar Giaever; famously independent physicist and author, Freeman Dyson; environmentalist futurist, and father of the Gaia Hypothesis, James Lovelock; left-center chemist, Fritz Vahrenholt, one of the fathers of the German environmental movement, and many others who would bristle at being lumped into the conservative camp.
Whether increasing CO2 in the atmosphere is bad or good is a question of science. And in science, truth and facts are not the playthings of causes, nor a touchstone of political correctness, nor true religion, nor "what I tell you three times is true."
Humanity has always dealt with changing climate. In addition to the years of drought and excessive moisture described above, the geological record makes it clear that there have been longer-term periods of drought, lasting for many years as during the Dust Bowl of the 1930s to many decades or centuries. None of these past climate changes, which had a profound effect on humanity, had anything to do with CO2, and there are good reasons for skepticism that doubling CO2 will make much difference compared to natural climate changes.
It is increasingly clear that doubling CO2 is unlikely to increase global temperature more than about one degree Celsius, not the much larger values touted by the global warming establishment. In fact, CO2 levels are below the optimum levels for most plants, and there are persuasive arguments that the mild warming and increased agricultural yields from doubling CO2 will be an overall benefit for humanity. Let us debate and deal with serious, real problems facing our society, not elaborately orchestrated, phony ones, like the trumped-up need to drastically curtail CO2 emissions.
Roger W. Cohen
Fellow, American Physical Society
La Jolla, Calif.
Richard S. Lindzen
Massachusetts Institute of Technology
A version of this article appeared August 14, 2012, on page A14 in the U.S. edition of The Wall Street Journal, with the headline: 'Climate Consensus' Data Need a More Careful Look.