China is in the midst of an aggressive push to become the world's preeminent source of clean energy. And it's not just for the sake of the planet -- it sees clean tech as a way of boosting the economy. In addition to the jobs that come from producing solar panels and wind turbines (it's already a giant in those fields), it could sell unneeded electricity to other countries. One of the nation's key energy officials, Li Junfeng, has even gone so far as to say "coal is over" -- a sharp contrast to the current US government's eagerness to defend coal whenever possible.

If there's a problem, it's that the team-up may take a long time to get going. You might not see much emissions trading when China is currently focused on its very large domestic market, and the deal is more than a little lopsided when the world's most populous country is involved with a single US state. Both are hotbeds for eco-friendly tech, however, so it wouldn't be surprising to (eventually) see some progress that wasn't possible before.