We read about global warming raising sea levels. Does this hold
true for Lake Michigan as well? It does not, because Lake
Michigan and all the Great Lakes, unlike the oceans, are not the
final repository of the world’s water. The Great Lakes drain
into the Atlantic Ocean via the St. Lawrence River, and their
volume of outflow increases when the level of the lakes rises.
It’s a different for story with the oceans. Water, once it finds
its way into the world’s oceans, can’t drain out; it can escape
the oceans only by evaporation. Researchers believe sea-level
rise will be the result of melting land ice (mountain glaciers
and the Greenland ice cap) and accelerated “drainage” of ice
into the oceans from the icecaps of Greenland and Antarctica.
Thermal expansion of warming ocean water will also add
contribute to sea-level rise.