Paris Climate Agreement
196 parties adopted the Paris Agreement on climate change at COP21
December 12, 2015
The World Agrees on Climate
On December 12, 2015, representatives of 196 countries gathered in Paris and reached a landmark agreement to fight climate change. The Paris Agreement, as it came to be known, committed nations to limiting the rise in global average temperatures to well below 2 degrees Celsius above pre-industrial levels, with efforts to keep warming under 1.5 degrees. It was the first time nearly every country in the world had agreed to take action on climate change together. The deal was the result of years of difficult negotiations and represented a major diplomatic achievement, even if critics argued it did not go far enough.
How It Works
Unlike previous climate agreements, the Paris Accord did not impose specific cuts on each country. Instead, every nation was asked to set its own targets — called "nationally determined contributions" — and to update them over time with more ambitious goals. The agreement also included provisions for wealthy nations to help poorer ones finance the shift to cleaner energy. Transparency rules were put in place so countries could be held accountable for their commitments. The hope was that international peer pressure and the gathering momentum of clean energy technology would push countries to keep raising their ambitions.
A Fragile but Vital Agreement
The Paris Agreement faced immediate challenges. The United States, the world's second-largest emitter of greenhouse gases, withdrew from the accord under President Donald Trump in 2020, then rejoined under President Biden in 2021. Scientists warned repeatedly that the pledges made by countries were not enough to meet the temperature goals. Extreme weather events — wildfires, floods, droughts, and hurricanes — continued to grow more frequent and more severe. Yet the agreement remained the central framework for global climate diplomacy, a shared reference point for a challenge that no country can solve alone.