It's been going on for ages, without our help. It will likely continue to go on, influenced by who-knows-what constellation of forces. We may be one of the forces, hubris to think it so, really.
Find The Register (U.K.) article for more details. See the actual article preview in Nature. Hat tip to Lucianne.com for the link. The bottom line is from The Register's caption for the data graph:
Move along, nothing to see here.