Voters are rejecting climate policy as too costly with negligible results

There’s a lot of focus now on the politics of Paris. Will poor countries get the "climate aid" they want? Will China agree to reduce its growth, leaving millions more in poverty, by committing to far-reaching carbon cuts? What will be the wording of the treaty that emerges?

It’s easy to become cynical. Let’s instead take a step back and ask a much more interesting question: what would it take for Paris to succeed? By this, I don’t mean that the delegates manage to sign some kind of treaty. I mean, what would it take for Paris to have a real impact on climate change?

Marine cloud whitening, and other ideas. We have precious little to show for nearly 20 years of efforts to prevent global warming. Promises in Rio de Janeiro in 1992 to cut carbon emissions went unfulfilled. Stronger pledges in Kyoto five years later failed to keep emissions in check. The only possible lesson is that agreements to reduce carbon emissions are costly, politically arduous and ultimately ineffective. But this is a lesson many are hell-bent on ignoring, as politicians plan to gather again—this time in Copenhagen, Denmark, in December—to negotiate a new carbon-emissions treaty.