"The canary is dead"

"The Arctic is genuinely collapsing. Scientists used to call these things the canary in the mine. What they say now is, The canary is dead. We are at the top of Niagara Falls, Tina, in a canoe. There is an image for your viewers. We got here by drifting, but we cannot turn around for a lazy paddle back when you finally stop pissing around. We have arrived at the point of an audible roar. Does it strike you as a good time to debate the existence of the falls?"  ~Barbara Kingsolver, Flight Behavior, p. 367

Digby nails it.

My question to climate change deniers is this: what if you're wrong? The only thing that will happen if the world addresses climate change will be a somewhat orderly change in the way we use energy, some economic reorganization and a whole lot of jobs and business being done to switch to different energy sources. The changes that are being proposed to mitigate climate change are far less cataclysmic than the changes that would be imposed by unaddressed climate change itself. Therefore, a fairly simple risk assessment suggests that anyone with a brain should take the prudent course and assume that the consensus that climate change is man made is the correct one and take steps to deal with it before it's too late.

"What if," indeed.