BY DENNIS T. AVERY
CHURCHVILLE VA—Now it’s not just the sunspots that predict a 23-year global cooling. The new Jason oceanographic satellite shows that 2007 was a “cool” La Nina year—but Jason also says something more important is at work: The much larger and more persistent Pacific Decadal Oscillation (PDO) has turned into its cool phase, telling us to expect moderately lower global temperatures until 2030 or so.
For the past century at least, global temperatures have tended to mirror the 20-to 30-year warmings and coolings of the north-central Pacific Ocean. We don’t know just why, but the pattern of the last century is clear: the earth warmed from about 1915 to1940, while the PDO was also warming (1925 to 46). The earth cooled from 1940 to 1975, while the PDO was cooling (1946 to 1977). The strong global warming from 1976 to 1998 was accompanied by a strong and almost-constant warming of the north-central Pacific. Ancient tree rings in Baja California and Mexico show there have been 11 such PDO shifts since 1650, averaging 23 years on length.
Researchers discovered the PDO only recently—in 1996—while searching for the reason salmon numbers had declined sharply in the Columbia River after 1977. The salmon catch record for the past 100 years gave the answer—shifting Pacific Ocean currents. The PDO favors the salmon from the Columbia for about 25 years at a time, and then the salmon from the Gulf of Alaska, but the two fisheries never thrive at the same time. Something in the PDO favors the early development of the salmon smolts from one region or the other. Other fish, such as halibut, sardines, and anchovies follow similar shifts in line with the PDO.
The PDO seems to be driven by the huge Aleutian Low in the Arctic—but we don’t know what controls the Aleutian Low. Nonetheless, 22.5-year “double sunspot cycles” have been identified in South African rainfall, Indian monsoons, Australian droughts, and rains in the United States’ far southwest as well. These cycles argue that the sun, not CO2, controls the earth’s temperatures.
Dr. Henrik Svensmark’s recent experiments at the Danish Space Research Institute seem to show that the earth’s temperatures are importantly affected by the low, wet clouds that deflect more or less solar heat back into space. The number of such clouds is affected, in turn, by more or fewer cosmic rays hitting the earth. The number of earthbound cosmic rays depends on the extent of the giant magnetic wind thrown out by the sun.
All of this defies the “consensus” that human-emitted carbon dioxide has been responsible for our global warming. But the evidence for man-made warming has never been as strong as its Green advocates maintained. The earth’s warming from 1915 to 1940 was just about as strong as the “scary” 1975 to 1998 warming in both scope and duration—and occurred too early to be blamed on human-emitted CO2. The cooling from 1940 to 1975 defied the Greenhouse Theory, occurring during the first big surge of man-made greenhouse emissions. Most recently, the climate has stubbornly refused to warm since 1998, even though human CO2 emissions have continued to rise strongly.
The Jason satellite is an updated and more-accurate version of the Poseidon satellite that has been monitoring the oceans since 1992, picking up ocean wind speeds, wave heights, and sea level changes. Jason is run by NASA’s Jet Propulsion Laboratory and a French team.
How many years of declining world temperature would it take now—in the wake of the ten-year non-warming since 1998—to break up Al Gore’s “climate change consensus”?
DENNIS T. AVERY is a senior fellow for the Hudson Institute in Washington, DC and is the Director for the Center for Global Food Issues. (www.cgfi.org) He was formerly a senior analyst for the Department of State. He is co-author, with S. Fred Singer, of Unstoppable Global Warming Every 1500 Hundred Years, Readers may write him at PO Box 202, Churchville, VA 2442 or email to cg...@hughes.net