Beware global cooling?

Dear Editor:I noticed that solar activity was not even mentioned in your recent article on Aspen’s climate change study (Aspen Times, June 25). Yet researchers have already determined some of the Earth’s recent cooler periods coincided with periods of low sun activity. The most recent period was from 1645-1715, when a drastic reduction in the number of sunspots (known as the Maunder Minimum) corresponded with a mini-ice age. The same correlation with cooler weather has been shown from 1420-1530 (the Spoerer Minimum), 1280-1340 (the Wolf Minimum), and 1010-1050 (the Oort Minimum). From 1100-1250, there were was more sunspot activity than normal, and that’s when the Vikings settled parts of Greenland. All of this was prior to any significant human activity.We now know that the recent 60 years of increased sun activity are the greatest period of such activity in the last 8,000 years. It is entirely possible that global warming may have little to do with human activity and much more to do with the variable output of the sun. Indeed if the sun returns to its historic average, global cooling may be more of a concern.As you mentioned in your article, “most with either an obvious stake in the impacts of global warming or an environmental bent,” it is most likely that a very slanted study with incorrect conclusions will result. Does the computer model even include the effects of the sun? The atmosphere is 78 percent nitrogen, 21 percent oxygen and 1 percent other. Of this 1 percent (100 parts in 10,000) other, the Mauna Loa observatory in Hawaii measured carbon dioxide as being just 3 parts in 10,000 of the atmosphere in 1958. It has increased .6 parts in 10,000 in the last 50 years. A solar output change of just .2 percent would be the equivalent of doubling the carbon dioxide concentrations. Since solar output is the highest it has been in 8,000 years, it is more than reasonable to expect that it is the principle, if not the primary contributor to global warming and should be the primary issue studied. If the sun is indeed the primary contributor, appropriate efforts by Aspen and the rest of the world might be to increase greenhouse gases to counteract the coming mini ice-age as sunspot activity swings to historic averages or lower. Mike MasonCedaredge, Colo.