The federal Great Lakes Compact, which took effect in December, is a good first step. But according to a new report in the journal Eos, a lot more has to be done to ensure our region’s freshwater supply remains steady and history doesn’t repeat itself.

John King, a geological oceanographer at the University of Rhode Island in Narragansett, told Discovery News that about 8,500 years ago, climate change pushed the lakes 66 feet below current levels, essentially cutting off the bodies of water from each other.

The scientists ascribe the change to a sustained drop-off in rainfall following the relocation of glaciers, which left significantly cooler and dryer weather behind. “We looked at all the evidence we could find, and there’s no other explanation,” King said. “This means that the idea that the lakes are insensitive to climate change is incorrect.”

If they aren’t, the Upper Midwest could be in for a world of hurt.  After all, more than 33 million people depend on the Great Lakes for fresh drinking water, hydropower, and the shipment of goods.

(H/T Mick Dumke)