I have a PhD in Atmospheric and Ocean Sciences, and have been thinking about climate pretty constantly since about the time of Hansen's infamous congressional testimony in a heat wave in 1989. I have a semi-famous blog about it which you can find if you look for my name, Michael Tobis.
I have a Climate Change SOS item I'd like to throw in the hopper. I realize I'm backing into it endlessly with these introductory paragraphs, but I still have this PhD and still in some sense represent science, so understand that this caveat is necessary for me to keep my union card. But other than this preliminary hemming and hawing, it is only one sentence, and that is something I deeply recommend that everyone interested in the climate problem understand and keep in mind.
The sentence is only approximately true. There are a bunch of caveats and hems and haws attached to this as a statement from a scientist. But it IS approximately true, and as you plan what to do you need to act as if it were pretty much true, because it is. So without further caveats:
The only game in town is the Last Ton game, where the lower the amount of fossil fuels burnt before the last ton is burnt, the better the ultimate result is for humanity and pretty much all other species.