Iowa is flooding. Again! It won't be long before it reaches Wisconsin, where I live.
Millions of years ago, the central part of what is now North America, was covered by a shallow inland sea, called the Western Interior Seaway.
Global temperatures were warmer then, and the resulting higher sea levels created the conditions necessary for the creation and maintenance of a sea dividing North America into east and west halves.
I wonder if the current increased level of flooding in the Midwest is the precursor to the return of an inland sea. It has to start somewhere, and rapidly rising global temperatures would certainly provide similar conditions to what existed in the Cretaceous era.
My prediction would be that rising sea levels and massive flooding of the central continent, in conjunction with the large scale erosion of the central plains due to agriculture, would eventually create the conditions for another semi-permanent shallow inland sea. The increased frequency of flooding along the Mississippi River and it's tributaries might be the early signs of this geological progression, which happens at a much slower scale than humans can conceive.
Essentially, the mouth/delta of the Mississippi would begin to transgress into the central lowlands of the state of Louisiana, which currently has a mean elevation of only 100 feet above sea level. Almost 20% of Louisiana's surface area is currently water-covered. The highest point in Louisiana is only 535 feet (a tenth of a mile) above sea level, and it's lowest point (in New Orleans) is actually eight (8) feet below sea level, as Hurricane Katrina so devastatingly illustrated.
The highest point in the state of Mississippi is only 800 feet above seal level. The mean elevation of the state of Arkansas is 650 feet above sea level, and that of Missouri is 800 feet above current sea level.
The mean elevation of the state of Iowa is 1,100 feet above sea level, but this state often experiences massive flooding because of high levels of rainfall and the large number of river basins (and associated floodplains) it contains, all of which are tributaries of the mighty Mississippi.
I could be wrong, but reality waits for no man.