This deliciously contrarian article by Patricia Adams and Lawrence Solomon suggests that our planet is increasingly green, no thanks to the environmentalist mania of the last half-century in Western countries:

The planet’s ecology is thriving thanks to carbon dioxide, despite first world policies that are undermining it. The ironic benefactors in this story are countries of the third world, led by China, whose emissions are doing the most to green the planet.

Up, up, up. Carbon dioxide, also known as “nature’s fertilizer,” has steadily been enriching Earth’s atmosphere, from 320 parts per million in 1970 to 365 parts in 2000, to more than 412 parts today. The evidence of a flourishing planet—once anecdotal—is now plain to see, thanks to satellite imagery that has been monitoring the amount of greenery on the planet since 1979.

This seems plausible to me, but you don’t have to buy it to take the lesson.  Nature has a process for addressing CO2 (plants) and a process for dealing with increases and decreases (expansion or contraction of green areas).  Your models of the future have to account for this, and you can’t really say whether such changes are good or bad until you’ve got decades to watch how things play out… especially when your proposed solutions force people to struggle in the present.