The past is indeed the key to the future – 10 Nov 09 – Recent laser imaging of the Earth’s surface provides new evidence for abrupt, fluctuating, warm and cool climatic episodes that could not have been caused by changes in atmospheric CO2, nor by humans.
In a paper presented at the national meeting of the Geological Society of America in Portland, Oregon, Professor Don J. Easterbrook, Professor of Geology at Western Washington University, presented new data showing that at least 9 significant, abrupt periods of climate warming occurred between 11,700 and 10,250 years ago. These warmings triggered retreat of the Cordilleran Ice Sheet.
Such fluctuating periods of warming and cooling persist to this day (with no help from humans), and there is every reason to expect them to continue.
“Isotope data from Greenland ice cores show a consistent pattern of fluctuating warm and cool periods over the past 500 years (Fig. 2),” says Easterbook. “The average period of warming/cooling oscillations over the past 500 years is 27 years, remarkably similar to the period of alternation between warm and cool Pacific Decadal Oscillation.”
Figure 2. Paleotemperatures derived from oxygen isotope measurements of the GISP2 Greenland ice core. Red peaks are times of warming and blue are times of cooling. The average time period for each climatic oscillation is 27 years.
“What we can learn from this geologic climate changes is that the past is indeed the key to the future,” Easterbrook continues. “In 1999, the year after the warmest year of recent times, I projected the climate pattern from the past century and past 500 years into the future and predicted that we would be due for 25–30 years of global cooling beginning about 2000. The PDO changed from its warm to cool mode in 1999 and since then we have had global cooling, quite moderate to flat (interrupted by two warm El Ninos) and intensifying since 2007.”
Figure 4. Projection of climate changes of the last century and past 500 years into the future. The black curve is temperature variation from 1900 to 2009; the red line is the IPCC projected warming from the IPCC website in 2000; the blue curves are several possible projections of climate change to 2040+ based on past global cooling periods (1945-1977; 1880 to 1915; and 1790 to 1820).
The lack of sun spots during the past solar cycle has surpassed all records since the Dalton Minimum and some solar physicists have suggested we may be headed for a Dalton or Maunder type minimum with severe cooling.
See entire paper by Don Easterbrook entitled
“New geologic evidence of past periods of oscillating, abrupt warming, and cooling”
Abrupt warming and cooling – Easterbrook