Christopher Monckton reminds everyone the United Nations Intergovernmental Panel on Climate Change (IPCC) previously published reports about climate change in 1990, 1995 and 2001. The summary report released today is the fourth revision so the latest conclusions can and should be compared to the past track record. Monckton provides us with this comparison in a 10 page PDF format. Let me highlight a few points.
IPCC Fourth Assessment Report 2007: FIGURES in the final draft of the UN’s fourth five-year report on climate change show that the previous report, in 2001, had overestimated the human influence on the climate since the Industrial Revolution by at least one-third. Also, the UN, in its 2007 report, has more than halved its high-end best estimate of the rise in sea level by 2100 from 3 feet to just 17 inches. It suggests that the rate of sea-level rise is up from 2mm/yr to 3mm/year – no more than one foot in a century.
UN scientists faced several problems their computer models had not predicted. Globally, temperature is not rising at all, and sea level is not rising anything like as fast as had been forecast. … The report’s generally more cautiously-expressed projections confirm scientists’ warnings that the UN’s heavy reliance on computer models had exaggerated the temperature effect of greenhouse-gas emissions. Previous reports in 1990, 1995 and 2001 had been progressively more alarmist. In the final draft of the new report there is a change in tone. Though carbon dioxide in the air is increasing, global temperature is not.
Computer models heavily relied on by the UN did not predict the considerable cooling of the oceans that has occurred since 2003 – a cooling which demonstrates that neither the frequency nor the intensity of the hurricanes in the year of Katrina was attributable to “global warming”. The UN’s models also failed to predict the halt to the rise in methane concentrations in the air that began in 2001. And they did not predict the timing or size of the El Nino which hiked temperature in 1998. Without it, the satellite record shows little or no greenhouse warming. Landbased temperature records may accordingly overstate the problem. Likewise the UN’s models have recently been found to have over-projected the observed rise in sea temperatures, which has had to be corrected downward to allow for over reading by incorrectly-calibrated instrumentation.
The UN’s draft Summary for Policymakers contains no apology for the defective and discredited “hockey-stick” graph that erroneously abolished the warm climate of the Middle Ages, arousing in some minds the suspicion that the intellectual honesty of the IPCC process is deficient. Ambiguities in the report, and considerable discrepancies between it and its predecessor, show that there is no scientific consensus on many points for which consensus is often claimed. Overall, however, the report is drafted so as to allow environmental extremists to cite its high-end projections as evidence of the need for urgent action.
