In the Science and Environmental Policy Project’s The Week That Was, Ken Haapala writes:
As the global climate refuses to obey the global climate models, advocates of the position that human emissions of carbon dioxide are the principal cause of late 20th century warming are attacking skeptics as anti-science. In effect, they are writing that the skeptics are nihilists – denying that scientific knowledge is possible. These alarmists are misrepresenting the position of most skeptics, namely that climate science as articulated by the UN Intergovernmental Panel on Climate Change (IPCC) fails to meet the standards of rigor required by modern science. …
The IPCC has failed to establish a strong link between changes in atmospheric carbon dioxide concentrations and changes in temperatures; contrary to the claims of Al Gore, Antarctic ice cores reveal that B (changes in temperatures) comes before A (changes in atmospheric carbon dioxide concentrations.)
The first two assessment reports of the IPCC contained the temperature variation of the past 1000 years derived from the best available data. These included the Medieval Warm Period and a Little Ice Age. The Third Assessment Report (AR3) replaced the historic data with the infamous “hockey-stick,” without explanation. The Forth Assessment Report (AR4) dropped the “hockey-stick” without explanation and limited the scope to the past 50 years. This is terribly misleading and clearly indicates the models on which AR4 relies cannot explain historic temperature variation. An examination of the best available data on temperature variation for the past 20,000 years (from Greenland ice cores backed up by other data) shows wild variation unrelated to atmospheric carbon dioxide, which the IPCC ignores.
As pointed out by Nir Shaviv and others, actual temperatures are significantly diverging from model projections. Warming alarmists are trying to explain away this divergence with irrelevant claims, such as 2011 was the ninth warmest year on (the instrument) record. But as reader Don Rapp points out, it was also the ninth coldest year in the last 13. What the IPCC does in its next assessment report is difficult to guess, but one can expect a clever effort to avoid rigorous science in establishing the relationship between atmospheric carbon dioxide concentrations and temperature changes.
However, in the interim, those accusing the skeptics of being anti-science are actually finding fault with skeptics because the skeptics are applying the principles of science far more rigorously than the IPCC applies them. Given the divergence between model projections and actual temperatures, any studies based on IPCC model projections are pure speculation.