I've been offline for many hours and am just now seeing the announcements from Beijing. The United States and China have apparently agreed to do what anyone who has thought seriously about climate has been hoping for, for years. As the No. 1 (now China) and No. 2 carbon emitters in the world, and as the No. 1 (still the U.S.) and No. 2 economies, they've agreed to new carbon-reduction targets that are more ambitious than most people would have expected.
We'll wait to see the details—including how an American president can make good on commitments for 2025, when that is two and possibly three presidencies into the future, and when in the here-and-now he faces congressional majorities that seem dead-set against recognizing this issue. It's quaint to think back on an America that could set ambitious long-term goals—creating Land-Grant universities, developing the Interstate Highway System, going to the moon—even though the president who proposed them realized that they could not be completed on his watch. But let's not waste time on nostalgia.
Before we have all the details, here is the simple guide to why this could be very important.
1) To have spent any time in China is to recognize that environmental damage of all kinds is the greatest threat to its sustainability—even more than the political corruption and repression to which its pollution problems are related. (I'll say more about this connection some other time, but you could think of last week's reports that visiting groups of senior Chinese officials bought so much illegal ivory in Tanzania during a state visit that they drove the black market price to new highs. [I've changed the description of these allegations slightly from the first-posted version.])
You can go on for quite a while with a political system like China's, as it keeps demonstrating now in its 65th year. But when children are developing lung cancer, when people in the capital city are on average dying five years too early because of air pollution, when water and agricultural soil and food supplies are increasingly poisoned, a system just won't last. The Chinese Communist Party itself has recognized this, in shifting in the past three years from pollution denialism to a "we're on your side to clean things up!" official stance.