Well, for one, surviving on a superheated planet, once the rising Arctic temperatures cause the permafrost to melt, releasing huge amounts of methane that cause a runaway feedback loop of global heating. If temperatures get hot enough, we could even see the oceans evaporate, and water vapor is a super greenhouse gas, further compounding the feedback loop, until it is dissipated back into hydrogen and oxygen by solar radiation, and the hydrogen vanishes into space while the oxygen recombines with carbon (its equilibrium state) to heat the atmosphere even more rapidly — like Venus. Only the super-rich will be able to survive that — and even then, what good will all their money and toys be? Money is, after all, nothing but arithmetic. And where will they get their fresh food and water? Sorry — techno-optimism is a delusion like any other. In the final analysis we are still animals, like any other, who rely on an intact, self-sustaining biosphere to survive. And when that collapses from excess trapped heat, so do we.