Thursday, November 20, 2014

Flashback: Climate scientists said warming decreases lake-effect snows

...but have conveniently changed their tune with the recent record-breaking lake-effect snow in the Buffalo area to claim global warming increases lake-effect snowfall. Four papers below collected by commenter Kenneth Richard find otherwise:

Global warming causes lessmore snow
Kenneth Richard November 19, 2014 at 11:33 PM

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.
3) Assessment of Potential Effects of Climate Change on Heavy Lake-Effect Snowstorms Near Lake Erie
...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.
4) Another one, from 1971, that says that global cooling (during the 1970's ice age scare) contributed to increased lake-effect snowfall during the 1940s to 1970s, and global warming (during the 1920s and 1930s) contributed to decreased lake-effect snowfall.

Lake effect snowfall to the lee of the Great Lakes, its role in Michigan
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].


  1. Lake effect snowfall is a product of temperature differentials rather than absolute temperatures.

    Thus it will increase from either warmer water or colder air and decrease from either colder water or warmer air.

    In this case we know that the water is colder than normal this year so the only way to get this sort of heavy lake effect snowfall is for the air to be even colder than normal than was the water.

    And so it was.

    1. Why have I read that the lake was warmer than usual? I would have expected it to be colder since ice was so thick last winter and it took longer to melt. And I know that I have also seen people who agree with you that the lake was colder. But then what is the basis for some of these claims that the lake is warmer than "usual". Temperature anomalies since 1950? Or compared to the typical 30 year reference period?

  2. The Kunkel, Wescott, and Kristovich paper, #2 above, not only projects that warming will decrease lake-effect snowfall in the future (late 21st century), but that *cooler* temperatures in the 1930s to 1970s produced *more* lake-effect snow, once again contradicting the currently popular theory that global warming and less ice cover produces more lake-effect snow:
    "Recent studies show that past changes in lake-effect snowfall on decadal time frames were related to climatic shifts. For example, lake-effect snowfall on the lee shore of Lake Michigan increased from the 1930s into the 1970s – coincident with a decrease in mean winter temperature."

  3. "Climate scientists said warming decreases lake-effect snows...but have conveniently changed their tune..."

    I doubt I'm alone in thinking the term "scientist" here is misapplied.