With the major downsides of climate change not occurring until 25 to 50 years from now, its effects will be viewed as important primarily by our grandchildren, if any still survive the apocalyptic versions.  

Whether the totally and completely voluntary goals of the Paris Accords ever happen in China or India or the United States, or not.

More people are going to die tomorrow and next week and next month and next year in Syria and Afghanistan and Iraq with or without the Paris Accords.  The Accords won't stop the refugees from Libya or from Syria or anywhere else from dying while trying to escape being killed.