This week is Climate Week in New York, when President Obama, Pope Francis, and many other world leaders converge to continue hammering out commitments intended to limit global warming to 2 degrees C or less, to be presented at the make-or-break COP21 climate meetings in Paris in early December.

The commitments are not there yet–so far those on the table would allow enough greenhouse gas emissions to raise temperature 3 degrees C or more. But staying below 2 degrees is critically important, for we already are seeing climate-triggered problems arise, even though global temperature has only risen less than one degree (0.9 degree C) above what used to be normal, and indeed what human civilization evolved in.

Read the rest at Huff Post Science Blog