Storms more powerful than have ever been recorded in history, melting of most of the ice on the poles, inundation of coastal cities due to sea level rise, and many other catastrophes that will be out of our control are predicted before the end of this century.
From New York Times contributor Justin Gillis, on March 22, 2016:
In 2009, nations agreed to try to limit the planetary warming to 3.6 degrees Fahrenheit, or 2 degrees Celsius, above the preindustrial level. The Earth has already warmed by about half that amount. The climate appears to be destabilizing, virtually all land ice on the planet has started to melt, and the oceans are rising at an accelerating pace.
The paper, written by Dr. Hansen and 18 other authors, dwells on the last time Earth warmed naturally, about 120,000 years ago, when the temperature reached a level estimated to have been only slightly higher than today. Large chunks of the polar ice disintegrated then, and scientists have established that the sea level rose 20 to 30 feet.
Climate scientists agree that humanity is about to cause an equal or greater rise in sea level, but they have tended to assume that such a large increase would take centuries, at least. The new paper argues that it could happen far more rapidly, with the worst case being several feet of sea level rise over the next 50 years, followed by increases so precipitous that they would force humanity to beat a hasty retreat from the coasts.
“That would mean loss of all coastal cities, most of the world’s large cities and all their history,” Dr. Hansen said in a video statement that accompanied the new paper.