Great Lakes Won't Cooperate With Climate Alarmists

"Faster than ever before.” That’s how one headline from the Weather Channel described current changes in Great Lakes water levels. But the article itself acknowledged that Lakes Huron and Michigan, which come together in the Straits of Mackinac and so are considered one lake by hydrologists, actually rose faster 65 years ago. So why did the headline writer call the current rise “faster than ever before?"

For more than a decade, those who claim man-made global warming is "settled science" exploited below-average Great Lakes water levels to promote their hypothesis. Although the period from 1999 to 2013 set fewer records than previous low-water spells, it was repeatedly portrayed by environmentalists and their media allies as clear evidence of climate change.

This contention became untenable when water levels began increasing rapidly in the second half of 2013. Instead of accepting that their arguments were being washed away, those promoting man-made global warming latched on to the increase as evidence of an “extreme weather phenomenon” attributable to global warming.

Never mind that 65 years ago this body of water displayed an even faster rise.

“What we are saying is that the water level increase on Lake Michigan-Huron beginning January 2013 through 2014 is rivaled only by the increase that occurred between January 1950 and December 1951,” said Keith Kompoltowicz, chief of watershed hydrology for the Army Corps of Engineers in Detroit. “The criteria we’re using for comparison are increases over a 24-month period.”

The 1950-51 increase was slightly greater than the recent increase, yet media accounts create the impression that the latter was unique. Some articles that have since been removed from the Internet said precisely that. Others, like the one cited above, tried to have it both ways, suggesting the recent rise was unique while acknowledging the earlier rise was bigger.

Some who promote man-made global warming focus on what they refer to as the unprecedented 15-year period of lower-than-average Great Lakes water levels. First, the recent low levels prevailed for 14 years, not 15. More importantly, the “precedents” are all confined within the narrow 98-year period during which the Army Corps of Engineers has been taking measurements. This period includes just three distinct low-water-level episodes.

Of course, for most of the 4,000-plus years the Great Lakes have existed in their modern form (they first came into being around 10,000 years ago) no one was systematically tracking water levels. But the United States Geological Survey, which studies the geological evidence of water level changes going back millennia, says the swings were far more extreme in the distant past than in recent centuries.

USGS studies also indicate a roughly 400-year spell of near-drought conditions in the Great Plains and Great Lakes regions corresponding to the Medieval Warming Period. It is likely that the Great Lakes experienced frequent spells of low water levels while those conditions predominated, and some of those low level periods lasted longer than 14 years.

The 2013-2014 increase was the largest recorded for Lake Superior over a 24-month period — the largest during the 98 years for which records exist, that is. But Lake Superior water levels also recovered very quickly from the lowest recorded level in 1926, reaching above-average levels in 1927. But that increase does not qualify under the "within 24-months" criteria.