evidence: "Our atmosphere and oceans can absorb only so much heat before climate change, intensified by various feedback loops, spins completely out of control. The consensus among scientists and policy-makers is that we’ll pass this point of no return if the global mean temperature rises by more than two degrees Celsius (maybe a little more, but also maybe a little less)… In the long run, it probably makes no difference how badly we overshoot two degrees; once the point of no return is passed, the world will become self-transforming." Here are the key lines: "The consensus among scientists and policymakers" is that above 2 degrees Celsius or a little more, the climate "spins completely out of control". This is just wrong, and Franzen provides no evidence to back up this extraordinary claim. Yes, positive feedback loops like widespread, fire-driven deforestation or massive methane releases could collectively drive the planetary temperature upwards in an ever less controllable spiral. These are possibilities, risks we need to reduce. Indeed, the risks get higher the more global warming pollution we emit, yet another critical reason to aggressively reduce it now. But I know of no scientific source—let alone a "consensus"—maintaining that such a "self-transforming" runaway greenhouse scenario is inevitable or that it will be triggered at close to 2 degrees Celsius. Without this assertion, Franzen’s "too late" argument falls apart. Four degrees will be far worse than three, which will be far worse than two. So we have to fight like hell today for two or better.