|Global warming causes lessmore snow|
The record lake-effect snow in the Buffalo area (November 18-20, 2014) has been said to be caused by global warming…because less ice cover due to warming means more precipitation events in the form of snow…or so it’s claimed.
But scientists have, in the past, concluded that global warming causes reduced lake-effect snow, not increases in lake-effect snow:
A general increase in LCS [lake-contribution snowfall] from the early 1920s to the 1950–80 period [during the 1970’s ice age scare] at locations typically downwind of the lake was found. Thereafter, LCS decreased through the early 2000s, indicating a distinct trend reversal that is not reported by earlier studies. The reasons for this reversal are unclear. The reversal is consistent with observed increasing minimum temperatures during winter months after the 1970s, however.
Thus, there may be little change in the frequency of heavy lake-effect snow in the Lake Superior snowbelt and a substantial decrease in the southern Lake Michigan and Lake Erie snowbelts. Air-temperature [warming] was found to be the primary determining factor in reducing the frequency of heavy lake-effect events in this study…Anticipated regional impacts of climate change on lake-effect snow patterns – suggest almost no change [in lake-effect snowfall] in the northernmost belts but approximately a 50% decrease in southernmost belts.
…Surface conditions favorable for heavy lake-effect snow decreased in frequency by 50% and 90% for the HadCM2 and CGCM1 [models], respectively, by the late 21st Century. This reduction was due almost entirely to a decrease in the number of occurrences of surface air temperature in the range of −10 to 0°C, which in turn was the result of an increase in average winter air temperatures.
Evidence suggests that lake effect snowfall has significantly increased during the past several decades, particularly in Southern Michigan and Northern Indiana. While the observed changes cannot be definitively ascribed to any single factor, it seems likely that a general cooling of winter temperatures may be partially responsible for this climatic change. [M]any of the snowfall time-series curves for the lake stations show downward trends during the 1920’s and 1930’s, at the height of the recent warm period, and the more recent snowfall increase has coincided with a general world-wide cooling which has occurred in the last several decades [1940s-1970s]. Recent evidence derived from [isotope] analysis of ice core samples on the Greenland ice cap indicates a continuance of this cooling trend for another 20 or 30 years [through the 1990s].