Energy Secretary Steven Chu gave an interview to the LA Times a couple weeks back, saying that we’re going to lose 90% of the snowpack, California ag is doomed, and he isn’t even sure we can hold on to our cities. It was a strong statement and I generally approve of strong statements. It is a worse fate than I expect. I’ve said below that my prediction is losing a third of CA ag, and how we should do that.
Anyway, the New York Times today discussed Chu’s statements, got a bunch of opinions about whether it was too strong or irresponsible. Did experts think Secretary Chu was on target? The answers vary, but none of them said something that I think is really important.
Secretary Chu picked the most extreme prediction from the suite of models. You can argue over whether the models are accurate; you can debate whether you should pick the upper bound or lower bound; you could squabble over how the effects will play out in real life. But the thing that none of those experts said in that interview is that right now, we are exceeding the carbon emissions in the most extreme model. Further, effects are arriving faster than we expected. Based on what we are doing now, the worst case scenario is the floor.
It is plausible that the next decade will see a sharp reduction in emissions, if Pres. Obama prioritizes it. If China joins us (or leads us, for all I know), in ten years we could be back in the mid range of the climate models. But until that happens, when you see a climate prediction and it gives you a range, assume that we are outpacing the worst prediction.
LATER: Apparently MIT has revised their models to include current emissions levels.