New Data Cast Doubt on Alarmist Warming Predictions
Three papers in Science Express, published online on August 11 and scheduled for later publication in Science, have made a splash in the news media.
The first paper, "The Effect of Diurnal Correction on Satellite-Derived Lower Tropospheric Temperature," by Carl A. Mears and Frank J. Wentz, reexamines satellite temperature data.
The second, "Radiosonde Daytime Biases and Late-20th Century Warming," by Steven Sherwood, John Lanzante, and Cathryn Meyer, reexamines balloon radiosonde temperatures.
And the third, "Amplification of Surface Temperature Trends and Variability in the Tropical Atmosphere," by Benjamin Santer, Mears, Wentz, and more than a dozen additional authors, compares surface and atmospheric temperature trends.
Together, the three papers allow for greater accuracy in judging global temperature measurements.
Warming Slightly Greater
In the first paper, Mears and Wentz found an error in previous satellite data analysis, which had indicated a minor warming trend of 0.09º C per decade. After correction, the trend was shown to be slightly higher, at 0.12º C.
The news media have reported this adjustment as significant new evidence of human-induced global warming. However, the adjusted new figure is still very close to the minor warming previously detected by satellite and is still much less than the more significant warming of .2º C or more per decade predicted by alarmists.
Significantly, corrected balloon data presented in the second article agree with the minor 0.12º C warming detected by the satellites, rather than alarmists' claims of more significant warming.
Data Inconsistencies Remain
The third paper examines the theoretical expectation that the lower atmosphere should warm more quickly than the Earth's surface.
Greenhouse theory says (and its proponents' computer models calculate) that the atmospheric warming trend should be 30 percent greater than the surface trend. However, scientists have long pointed to a disparity that showed the atmosphere's lowest layer, the troposphere, has not warmed as much as the surface.
Furthermore, the alarmists' models predict polar trends should greatly exceed the tropical values, and they clearly have not done that. The Antarctic, for example, has been cooling for decades.
As Roy Spencer, principal research scientist at the University of Alabama Huntsville (UAH), wrote in an August 11 article for Tech Central Station, "The authors restate what had already been known: that the UAH satellite warming estimates were at odds with theoretical expectations (as had been some radiosonde measures). The convergence of these newly reported satellite and radiosonde estimates toward the surface warming estimates, if taken at face value, provides better agreement with climate models' explanation of how the climate system behaves."
UAH climatologist John Christy welcomed the first paper's reexamination of the satellite data that now puts it in agreement with balloon data.
"While some people might question the importance of a correction that changes the long-term trend by only 0.035ºC per decade, for us the most important thing is to produce a climate dataset that is as accurate and reliable as humanly possible," Christy said, according to an August 11 UAH news release.
"In a recent scientific comparison," stated the UAH release, "the UAH team found that the UAH satellite dataset agreed exceptionally well with several long-term temperature datasets prepared by NOAA, the National Centers for Environmental Prediction, the Hadley Centre of the British Meteorology Office, and the European Centre for Medium-Range Forecasts."
"This is a minor correction of three-hundredths of a degree, concentrated in the tropics," said Iain Murray, senior fellow at the Competitive Enterprise Institute. "The satellite data still suggest warming well below the levels the alarmists trumpet. Real-world data, as opposed to theoretical models, continue to point to a modest warming that humanity can easily adapt to."
Causes Still Unknown
"It is fairly obvious that some portion of this warming is probably due to human influences," added Spencer in the UAH news release. "What isn't clear is how much or which influences. And you have to overlay all of this onto the climate's natural instability."
"On the positive side," wrote Spencer in his Tech Central Station article addressing the new data, "at least some portion of the disagreement between satellite and thermometer estimates of global temperature trends has now been removed. This helps to further shift the global warming debate out of the realm of 'is warming happening?' to 'how much has it warmed, and how much will it warm in the future?'. (Equally valid questions to debate are 'how much of the warmth is man-made?', "is warming necessarily a bad thing?', and "what can we do about it anyway?'). And this is where the debate should be."
Mild Warming Likely
Pat Michaels, senior fellow in environmental studies at the Cato Institute, said the new data bolstered predictions that any future warming is likely to be mild. "The newly published research indicates that satellite, weather balloon, and surface temperature trends in recent years are all nearly the same, placing much greater confidence in the amount of global warming that is occurring," observed Michaels.
"These three different ways of measuring temperature have all converged on a warming rate that is at or near the low limit for warming given by scientists on the United Nations Intergovernmental Panel on Climate Change. These results reassure the arguments of those who say global warming is likely to be modest and they argue strongly against the alarmist point of view on climate change," Michaels noted.
"Right now the available data sets appear to strengthen the case for arguing that the lower-end model projections for future temperature increases are the more likely ones," Reason Foundation science correspondent Ronald Bailey noted in an August 11 column.
"The new warming trend is still well below ideas of dramatic or catastrophic warming," agreed Christy in the UAH news release.
S. Fred Singer (email@example.com) is professor emeritus of environmental sciences at the University of Virginia and president of the Science and Environmental Policy Project (SEPP) in Arlington, Virginia. He has held several federal government positions, including director of the U.S. Weather Satellite Service.
For more information ...
Abstracts for the three papers reviewed here are available online at http://www.sciencemag.org/sciencexpress/recent.shtml.