By the end of this century, atmospheric CO2 is expected to double over preindustrial levels. That's because of the world's widespread use of coal, oil, and natural gas since the start of the Industrial Revolution as well as changes in land-use patterns.
Yet the value of the agreement lies less in its immediate effect on the atmosphere than on the political and diplomatic chemistry needed to deal with a problem that is likely to take decades to solve, some analysts say.
The 1997 accord "puts real pressure on countries to deliver on their commitments. Countries will demonstrate that it can be done affordably. And most important, ratification sets in motion the diplomatic machinery" to look beyond 2012, Mr. Diringer says.
He notes that the accord requires signatories to begin talks next year on a new round of targets and timetables for emission reductions.
"This is the first step in what will need to be a decades-long process," adds David Sandalow, a Brookings Institution scholar who has served as assistant secretary of state for oceans, environment, and science under President Clinton.
By most accounts, the European Union is in the vanguard of efforts to implement the Kyoto accords. The EU has set up a carbon-emissions trading scheme, which takes effect in January, according to David Victor, director of the Program on Energy and Sustainable Development at Stanford University in Palo Alto, Calif. In addition, it has developed a set of voluntary and binding regulations to cover households, transportation, and the building sector.
The EU is likely to fall a little short in meeting its Kyoto targets on its own, he says, but Russia's participation will come to Europe's rescue.
Because the Russian economy was in such shambles in 1990, the base line against which Kyoto targets are measured, Moscow's emissions targets are far above existing emissions. So Russia has carbon "credits" it can sell to EU members.