TheKyoto protocolwas the first agreement between nations to mandate country-by-country reductions in greenhouse-gas emissions. Kyoto emerged from theUN Framework Convention on Climate Change(UNFCCC), which was signed by nearly all nations at the 1992 mega-meeting popularly known as the Earth Summit. The framework pledges to stabilize greenhouse-gas concentrations "at a level that would prevent dangerous anthropogenic interference with the climate system". To put teeth into that pledge, a new treaty was needed, one with binding targets for greenhouse-gas reductions. That treaty was finalized in Kyoto, Japan, in 1997, afteryears of negotiations, and it went into force in 2005. Nearly all nations have now ratified the treaty, with the notable exception of the United States. Developing countries, including China and India, weren't mandated to reduce emissions, given that they'd contributed a relatively small share of the current century-plus build-up of CO2