International treaties

The atmosphere is pretty much transnational (despite progress on a very high wall between the United States and Mexico). So work on global warming needs to be international.

Kyoto Protocol

The Kyoto Protocol was a 1998 agreement under which all Earth's nations would transform their economies to roll back their emission of CO2 by 2010. (Again, progress would be measured against that alternate Earth that has no humans.) All the nations, that is, except the following:

The United States, which never ratified the Protocol, and whose Senate was almost unanimously against any treaty if it had teeth.
Latin America and Africa, where existing laws aren't enforced and open fires are a fixture. Rural folk burn off crops after harvest rather than plowing them under; city-dwellers gather around open fires in 50-gallon drums, as an ice-breaker for early morning booze-ups before proceeding to the factories.
Crowded and grimy China and India, which were specifically exempted; and
The European Union, which eagerly ratified the Protocol but never complied with it.
The Protocol gave special status to "early ratifiers," the valiant nations that signed on before thinking it through. Bottom line: Nothing happened.

Follow-on treaty

A successor to Kyoto is being developed for the Copenhagen meetings. The parties' negotiating positions are as follows:

The United States is newly receptive to a treaty, but insists on getting credit for its vast forested area. It says these trees store carbon that otherwise would be discharged as CO2 into the atmosphere. But other nations point to the large number of Americans living together without marriage; the lack of diamond rings, which are also carbon, implies that the U.S. is responsible for additional CO2.
China and India insist they are as crowded and grimy as ever and should still be exempt.
Third-world countries have hardened their position. Rather than agreeing to terms they'll never enforce, they now want rich nations to pay them to make the required changes. The checks would be payable to the various Presidents-for-Life, military strongmen, and tin-god dictators, to be spent on behalf of their needy populations. (The portion stored in numbered Swiss bank accounts backs their currencies.)