Paris Climate Agreement Signed

On December 12, 2015, 196 parties at the COP21 conference in Paris adopted the Paris Agreement — the most ambitious international climate treaty in history. Nations pledged to limit global temperature rise to well below 2 degrees Celsius above pre-industrial levels, with efforts to limit it to 1.5 degrees. Unlike Kyoto, the Paris Agreement required all countries — including developing nations — to submit nationally determined contributions (NDCs) for emission reductions. The agreement entered into force on November 4, 2016, in record time. While the U.S. temporarily withdrew under the Trump administration, it rejoined under Biden. The Paris Agreement established 1.5 degrees as the critical threshold and created a ratchet mechanism requiring nations to strengthen their commitments every five years.