Global Warming Facts, Consensus Melt Away
From TechCentralStation, 1 October 2001
The exaggeration over the supposed scientific consensus on the human cause of global warming continues, even as the evidence that the underlying data supposedly proving a human connection melts away. In the July 20 Science, three British researchers attempted to defend the scientific integrity of the joint World Meteorological Organization and United Nation's Intergovernmental Panel on Climate Change (IPCC) Third Assessment Reports. That's hardly a surprise. After all, these scientists shared authorship for both the assessment reports' Summary for Policymakers and the Technical Summary. But their defense crossed into hyperbole when they claimed: "Individual authors can always make assumptions that may be controversial in order to explore their implications, but IPCC reports, which are subject to a long and exhaustive review process, do not have the luxury. ... The IPCC is a cautious body, and if evidence is not available in the peer-reviewed literature to support a statement, it will not make it, no matter how great the interest in that statement might be."
These authors would have people believe that the IPCC makes no controversial claims and fully accounts for the uncertainties and the unknowns. The science, in short, about climate change is settled. And as the summary for policymakers proclaimed: "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities [i.e., the anthropogenic greenhouse gases, mainly carbon dioxide]." But this claim is empty. There is stronger evidence that it is not mankind that has caused global warming. It takes some hefty manipulation and illogical explanation of the data to show mankind has contributed anything at all. One key problem lies in the Technical Summary when it attempts to use surface temperatures and those of the troposphere, that layer of air up to 5 miles above the surface, to demonstrate human-caused warming. According to all the computer models, the troposphere temperature should warm faster than the surface air if carbon dioxide, the main greenhouse gas produced by man's burning fossil fuels, is really the culprit. It's a matter of physics. The more moist and warmer surface air is less affected by increases in CO2 than the less moist and cooler upper air. At the higher level CO2 both radiates energy back into space and down to the surface air to be absorbed.
The IPCC's Technical Summary, written in part by the three British scientists, claims that the temperature trends since 1958 for the lowest 5 miles of atmosphere and the surface are "in good agreement, ... with a warming of about 0.1 degree C per decade." To demonstrate this, a chart plotting the temperatures from 1958 to present is shown. The close agreement, if it existed, would not prove human-caused warming. As noted, the computer simulations forecast a greater warming for the troposphere than the surface. At the same time - as climate researchers know - a straight trend line as the Technical Summary provides is not the proper way to look at the data. This is especially so in this case as the starting point was cool, affected by Mount Agung's volcanic eruption. The end point is unusually warm, with the natural and cyclical 1997 - 98 El Nino event temporarily exaggerating warming at the end of the century. But that's not all. As climate experts know, there was a step-like shift in temperatures in the northern Pacific in 1976-77. It was strong enough to elevate global air temperatures both near the surface and in the troposphere. Climate models do not explain this abrupt Pacific climate shift.
This step-like rise argues against human-caused warming, which the computer models say should be a gradual trend over decades, not a jump within a year or two. Recent research results suggest that the 1976-77 climate shift is not unique. Instead, the Pacific alternately warms and cools about every two decades, according to recorded tree ring changes of the past few hundred years. And climate researchers have noted that the Northern Pacific temperatures since the summer of 1998 appear to be returning to lower levels. Such measurements suggest the resulting Pacific and global climate shifts are very unlikely to be caused by man and his burning of fossil fuels. That, though, is not the only fact that the Technical Summary's distortion of the temperature record glosses over. The Summary finds a contradiction to the idea of human induced warming: "Since the beginning of the satellite record in 1979, the temperature data from both satellites and weather balloons show a warming in the global middle-to-lower troposphere at a rate of approximately 0.05 +- 0.1C per decade. The global average surface temperature has increased significantly by 0.15 +- 0.05C/decade." This, as the summary admits, is a statistically significant difference. Left unsaid is the fact that the result runs counter to the forecast that the troposphere would warm faster than the surface.
The Summary continues on to an outlandish claim: "By contrast, during the period 1958 to 1978, surface temperature trends were near zero, while trends for the lowest 8 km (5 miles) of the atmosphere were near 0.2 C/decade." If this were true, then those who have claimed that the climate has changed by human actions would have their strongest proof. For then the troposphere did warm and surface temperatures didn't, just as the models suggest. Only this just did not happen. The claim is an error, and no minor one for such a prestigious and important report. The troposphere showed no warming trend, or perhaps cooled slightly, during that period. The only way to produce a warming trend as large as stated for the troposphere warming is to selectively calculate a trend only between 1964 and 1983, with 1983 affected by a strong El Nino warming event. Finally, the IPCC, in making predictions of future warming as high as 0.58 degrees C per decade, said this rate "is very likely [90-99% confident] to be without precedent during at least the last 10,000 [sic] years, based on paleoclimate data." But what is the scientific evidence for that claim? The troposphere and surface records together undermine such an alarmist claim.
Perhaps the new IPCC statements contain typos or other sorts of inadvertent errors. Yet the IPCC authors in their commentary in Science leave the impression there were none that mattered. There is no clear signal to proclaim scientifically the large global climatic effects by man-made carbon dioxide forecast to date. The many political reports by the IPCC for the last 11 years or so have not changed that. Funding would have been better spent on searching for understanding of the climate science itself.