Why were Lake Michigan and the other Great Lakes water levels near record lows between 2000 to 2017?

Global warming, we were told. Warming was evaporating the Great Lakes, Nobel Prize winning Al Gore said. Among others saying the same was Illinois Senator Dick Durbin. “What we are seeing in global warming is the evaporation of our Great Lakes,” he said, and asked the federal government for help.

Why were lake levels near record in 2020, causing extensive shoreline damage?

Undeterred by contradiction, it was global warming again, we were told. In fact, that’s when hysteria in Chicago about warming reached high tide.

“City of Chicago declares climate crisis after storms cause millions of dollars in damage to Lake Michigan shoreline” — that was an ABC News national headline. The claims from the City Council in its crisis resolution were as extreme as you can find on global warming. We had to end the “Sixth Mass Extinction,” it said, requiring “an emergency mobilization on a scale not seen since World War II…. Earth is already too hot for safety and justice.”

The resolution demanded a “just, managed divestment and phase-out of fossil fuels” and an end to “greenhouse gas emissions as quickly as possible to establish a zero-emissions economy.” And Senator Durbin again asked the federal government for help, this time saying global warming caused high water, the opposite of his earlier claim.

You can thank those policies, which were widely embraced in Chicago and elsewhere, for at least part of today’s high energy prices. But what’s a little pain at the pump when the “Sixth Mass Extinction” looms?

Now, Mother Nature once again hasn’t followed the script.

Lakes Michigan and Huron (which are connected and at the same level) alone lost 20 trillion gallons of water in just the last two years. Their level is down over two feet from the recent highs, putting them and other Great Lakes only an inch or two above average.

How does global warming account for that? A new explanation was described in a recent front page Chicago Tribune column: more variability in lake levels. “Climate change may be contributing to more pronounced variations” according to researchers, reported the Tribune. “This cycle of erosion and exposure is not new, it just appears to be occurring over a shorter period of time, scientists say.” The Tribune did not provide any support for its claim that “scientists say” that, but it is true that some do.

Let me be clear from the outset that I am not dismissing the possibility that variability in Great Lakes levels is increasing. I have little idea if it’s true. The point here, instead, is that this is yet another instance of climate claims changing when the facts don’t turn out to agree.

And there’s reason to maintain skepticism about the new theory.

For starters, is it really true that the cycle appears to be occurring over a shorter period of time?

Look for yourself at the Great Lakes levels since 1918. It certainly does not appear that variability has increased materially. Yes, there was an exceptionally big reversal between 2013 and 2020, but that that’s just one sequence, making it mighty thin evidence. And a particularly stable period seems to have occurred in the immediately preceding 13 years.

Maybe there’s another explanation for the big spike up in lake levels between 2013 and 2020. For that, there’s something called Occam’s Razor. That’s the principle that the simplest explanation is probably the right one.

What might that simpler explanation be? It rained a lot. That in fact was an explanation provided at the time by an atmospheric scientist at Argonne National Laboratory. “In a nutshell, the main reason is it really just has rained a lot,” he told WTTW. “Once [the soil] is saturated, all that water runs straight off into the Great Lakes rather than being absorbed into the soil and evaporated,” he said.

At least one scientist’s work I found does make a plausible case that Great Lakes water levels be going up and down further than before. However, his claims are very modest and conditional, and he makes them without the hubris and hyperbole that we often see in climate scientists.

That’s Drew Gronewold of the University of Michigan. His video presentation is here and his paper that he discusses is here. Based on a forward-looking model and the premise that temperatures are higher and it’s raining more often, his paper concludes that the chances of extreme departures from average lake levels like we’ve had recently are 2.1% or 3% more likely than the historical norms under two scenarios he modeled. That’s certainly not much to worry about.

It’s also worth remembering that if you want to look much further back in history and over longer periods you’ll find truly whopping variations in Lake Michigan levels.

In 1989 salvage divers found something they didn’t expect 15 miles out from Chicago Harbor: tree stumps. The stumps were the remains of a forest that radioactive dating indicated grew there some 8,000 years ago, now 80 feet underwater.

But by 5,500 years ago, the level had surged to over 20 feet higher than today. If you are familiar with Ridge Road around Chicago, you may know that it really is on a ridge for the most part. That ridge was once the shoreline. If you live east of it and dig down far enough, you’ll find sand.

The Tribune article also says “Climate scientists agree that storms and weather events in general are getting worse.” No, there’s no agreement on that. It’s hotly contested. Among those who disagree is Steven E. Koonin, former Undersecretary for Science under President Barack Obama in the U.S. Department of Energy. His arguments to the contrary are summarized here.

It’s hard for us who try to keep open minds about climate issues. It’s hard because so many claims change as often as the weather, because thin evidence is so often exaggerated, because “global warming” so often morphs into the entirely different topic of “climate change,” because Occam’s Razor is ignored, because warnings of things like the Sixth Mass Extinction are absurd and because scientific consensus is often claimed where it does not exist.

Please, make it easier for us.