Nations adopted the Kyoto Protocol on climate change

On December 11, 1997, after a marathon two-week summit in Kyoto, Japan, delegates adopted the Kyoto Protocol, the first international agreement to set legally binding targets for cutting greenhouse gas emissions. It extended the 1992 UN Framework Convention on Climate Change from voluntary aspiration into firm obligation.

The protocol bound industrialized countries—the historic source of most emissions—to reduce output of carbon dioxide and other heat-trapping gases over a set commitment period. The negotiations drew more than 10,000 participants and ran past their deadline as ministers haggled over numbers late into the night.

It was the first treaty to set legally binding targets to cut greenhouse gas emissions.

Getting from agreement to action proved slow. A tangled ratification process meant the protocol did not enter into force until February 16, 2005, and the United States ultimately never ratified it. Even so, Kyoto established the architecture—targets, timetables, and trading—that later climate deals, including the Paris Agreement, would build upon.