By Professor Don Easterbrook, Western Washington University
In 2007-2008, the Intergovernmental Panel on Climatic Change (IPCC) and computer modelers who believe that CO2 is the cause of global warming still predict the Earth is in store for catastrophic warming in this century. IPCC computer models have predicted global warming of 1F per decade and 5-6C (10-11F) by 2100, which would cause global catastrophe with ramifications for human life, natural habitat, energy and water resources, and food production. All of this is predicated on the assumption that global warming is caused by increasing atmospheric CO2 and that CO2 will continue to rise rapidly.
However, records of past climate changes suggest an altogether different scenario for the 21st century. Rather than drastic global warming at a rate of 0.5C (1F) per decade, historic records of past natural cycles suggest global cooling for the first several decades of the 21st century to about 2030, followed by global warming from about 2030 to about 2060, and renewed global cooling from 2060 to 2090 (Easterbrook, D.J., 2005, 2006a, b, 2007, 2008a, b); Easterbrook and Kovanen, 2000, 2001). Climatic fuctuations over the past several hundred years suggest ~30 year climatic cycles of global warming and cooling, on a general rising trend from the Little Ice Age.
See larger image here
Now a decade later, the global climate has not warmed 1F as forecast by the IPCC but has cooled slightly until 2007-08 when global temperatures turned sharply downward. In 2008, NASA satellite imagery confirmed that the Pacific Ocean had switched from the warm mode it had been in since 1977 to its cool mode, similar to that of the 1945-1977 global cooling period. The shift strongly suggests that the next several decades will be cooler, not warmer as predicted by the IPCC.
Global temperature projection for the coming century, based on warming/cooling cycles of the past several centuries. ‘A’ projection based on assuming next cool phase will be similar to the 1945-1977 cool phase. ‘B’ projection based on assuming next cool phase will be similar to the 1880-1915 cool phase. The predicted warm cycle from 2030 to 2060 is based on projection of the 1977 to 1998 warm phase and the cooling phase from 2060 to 2090 is based on projection of the 1945 to 1977 cool cycle. See larger image here
Global warming (i.e, the warming since 1977) is over. The minute increase of anthropogenic CO2 in the atmosphere (0.008%) was not the cause of the warming- it was a continuation of natural cycles that occurred over the past 500 years.
The PDO cool mode has replaced the warm mode in the Pacific Ocean, virtually assuring us of about 30 years of global cooling, perhaps much deeper than the global cooling from about 1945 to 1977. Just how much cooler the global climate will be during this cool cycle is uncertain. Recent solar changes suggest that it could be fairly severe, perhaps more like the 1880 to 1915 cool cycle than the more moderate 1945-1977 cool cycle. A more drastic cooling, similar to that during the Dalton and Maunder minimums, could plunge the Earth into another Little Ice Age, but only time will tell if that is likely. Read more here.