Related to chat w/ @levi_m & @philaroneanu, here’s why I don’t pick a climate number (degrees or ppm):
To me, choosing a number — 350, 450 or 550 parts per million, 2 or 3 degrees (F. or C.!) — is essentially meaningless for our generation, especially given the trajectories for emissions in China and India.
The task on emissions is twofold — to bend the curve of gas releases using regulations, incentives, education and standards, but (more importantly, to me) also to build the intellectual infrastructure and innovative, globally-collaborative culture that will be required for the next generation to take that curve down toward zero even as humanity’s energy needs continue to rise. My emphasis on the second component derives from all the biases toward the quick fix that are built into the human brain, political institutions and culture.