So how is that informal climate "accord" that came out of Copenhagen last December actually working out? A lot of outside observers seem to assume the summit was a huge flop—after all, it didn't even end with a tangible treaty. I still think the best way to look at Copenhagen is as a work-in-progress that could, with a lot of strengthening, have a positive impact. And here's a new paper from Trevor Houser at the Peterson Institute for International Economics that suggests something similar. It's a keen analysis of the current state of play.
First, some background: On February 1, the U.N. posted a list of countries that have voluntarily pledged to cut (or at least rein in) their greenhouse-gas emissions a certain amount by 2020. So far, 92 countries have made pledges, and they make up 83 percent of the world's emissions. So that's a good first step. Now, Houser looked at what would happen if all of those countries actually did what they're promising (bear in mind, that's hardly a given; the United States, for instance, won't meet its 2020 goals if the Senate refuses to pass a climate bill and also neuters the EPA.)
The end result would be… not too far astray of the mark. The agreed-upon goal, remember, is to keep global temperature increases below 2°C. To do that, climate models suggest that the world's emissions would need to peak at somewhere between 40 and 48 gigatons by 2020. The Copenhagen pledges would put us somewhere between 48 and 51 gigatons—or they would as long as there's international financing for poorer countries and as long as offsets don't get "double-counted" (i.e., a U.S. company pays for tree-planting in Brazil and both countries count that toward their goals). Not easy, but doable.
Houser then tries to model out the likely next steps through 2050 and concludes that, "if countries follow through on their pledges and follow on with more aggressive action, it looks like keeping global temperature increases below 2 degrees Celsius is still within reach. Of course, the more countries ratchet up mid-term action, the better the chances get. (Also, big caveat: This is all assuming the IPCC consensus on climate science is basically correct. If, instead, the views of scientists like James Hansen are closer to the truth, then we'd actually need much, much deeper emissions cuts—and in that case the world is screwed under Copenhagen.)
So, according to Houser's analysis, countries still need to be more ambitious in their pledges, but the Copenhagen accord has the world (very) roughly on track to meet its own climate goals. Then again, there are so many prickly questions looming—like how we measure and verify that countries like China are actually meeting their targets—that it's way, way too premature to declare this whole process a success.