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Other scientists believe that the earth is actually getting warmer. As they see it, the cooling trend of the '50s and '60s has leveled off and worldwide temperatures are rising. As evidence, they point to uncharacteristically mild winters during recent years in Scandinavia and, with the exception of this year, in New England. Temperatures in Australia and New Zealand as well as Antarctica have risen slightly. Glaciers in the Alps have retreated slightly, and temperatures measured at 40 scattered points in the middle latitudes of North America have either stayed the same or risen during the past six years.
If a warming trend is indeed under way, many scientists say it probably has been caused by increasing amounts of carbon dioxide (CO2) spewed into the atmosphere by the burning of coal and petroleum products. While the CO2 does not prevent solar radiation from reaching the earth, it blocks the escape into space of heat rising from the earth's surface—the so-called greenhouse effect.
To those shivering through the current winter's chill, that prospect has a certain appeal. But a global warming trend could be just as disastrous as a worldwide freeze. More than a modest rise in temperatures could melt polar ice caps, cause extensive coastal flooding, drastically alter air circulation and rainfall patterns, and cut the productivity of many important agricultural areas.
Only time and more research will reveal which, if either, of these scenarios is correct. But whatever the long-term forecast may be, scientists do agree on one thing: earth's climate is entering a period of increased variability in which weather patterns are likely to fluctuate far more dramatically than they have in the past few decades. Geise believes next winter's weather will be the reverse of the present pattern. His forecast should come as welcome news to the Southeastern U.S.—which would get warmer weather—and as a mixed blessing to the Mississippi and Ohio valleys, which may get too much rain. Californians may have less to be thankful for. They are likely to experience temperatures next winter as uncomfortable for their area as this year's readings are for the beleaguered East.