After decades of warnings from scientists that greenhouse gas emissions
were warming the planet, governments started coming together in the
1980s to combat the problem. Here's a timeline of key moments in the
diplomatic effort to stop global warming, leading up to the U.N. climate
conference in Paris:
1987: MONTREAL — Governments adopt a treaty pledging to restrict emissions of chemicals damaging the ozone layer. While it doesn't deal with climate change specifically, the Montreal Protocol becomes a model for how to rein in man-made emissions through international agreements.