I think the likelihood that we stay below two degrees even with diligent efforts was relatively small — maybe 20 percent, in my view — before the Trump withdrawal from Paris. And the likelihood is now increased markedly that we’re not going to make the two degrees. Personally I would rate the likelihood as under 10 percent. So I think we need to be prepared for a world where we are going to have eventually a large sea-level rise, for a world in which we have extended episodes of unbearable excess heat, for a world where eventually crop yields will decline significantly in parts of the world and cause food-security problems that go over the edge at least periodically, and that means more starvation and malnutrition. Where natural ecosystems like coral reefs, some of them, are going to be doomed. We’re probably already bought into a world we’re not going to like very much — and the likelihood of other surprising outcomes is increasing markedly.
source: michael oppenheimer in nymag.com
Now a professor at Princeton, Michael Oppenheimer was the longtime chief scientist of the Environmental Defense Fund’s Climate and Air program, and was an early force in the U.N. efforts on climate change/global warming that resulted, ultimately, in the Kyoto protocol.