I was educated by Stewart Brand and The Whole Earth Catalog. Helped me to see “the big picture” instead of a bunch of little ones. If humans are such bad care-takers of this planet, then the laws of evolution will take its course and in a few hundred or thousand years we will no longer be here. Then the earth will move on to the next phase of its existence.
You say 50 years is the timeframe for the changes you wrote about. To me you should move that starting point back another 50. At the end of the 19th century, industrial pollution from Western Europe & the US was unchecked and twice as deadly. By the 1960’s, everyone began to recognize something had to be done (Just as the Chinese are discovering today.)
But who knows? Maybe we’ll get lucky and the earth’s axis will shift those few degrees it periodically does, and turn the Sahara into the tropical paradise it occasionally becomes.