I saw an interesting educational program titled "drain the Great Lakes". It relates how a scant 20,000 years ago, which is literally a drop in the bucket in geological terms, there was a gigantic glacier a mile thick covering the Northern Hemisphere and 5,000 years ago the climate was so arid that the level of the Great Lakes was lower than it is now. The point is that there are forces in nature that make the Industrial Age look like child's play. Modern humans live in a relatively stable time in geological history and radical lefties still ain't happy.