Sorry, the full piece is in Times Select ($), but here is how it starts ... and ends:
The factual debate about whether global warming is real is, or at least should be, over. The question now is what to do about it.
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But California’s experience shows that serious conservation is a lot less disruptive, imposes much less of a burden, than the skeptics would have it. And the fact that a state government, with far more limited powers than those at Washington’s disposal, has been able to achieve so much is a good omen for our ability to do a lot to limit climate change, if and when we find the political will.