What major international climate agreement was signed on Earth Day 2016?

The Paris Agreement was the major international climate agreement signed on Earth Day in 2016.

The agreement was adopted in December 2015 at the United Nations climate conference near Paris, but it was opened for signature on April 22, 2016—Earth Day—at a ceremony held at UN headquarters in New York. That distinction matters: adoption finalized the negotiating text, while signature began the formal process for countries to join the treaty.

The Paris Agreement aims to keep the rise in global average temperature well below 2°C above pre-industrial levels and to pursue efforts to limit it to 1.5°C. It requires countries to submit and regularly strengthen national climate plans, known as nationally determined contributions.

The treaty is often confused with the Kyoto Protocol, an earlier climate agreement with more limited binding targets for developed countries. The Paris Agreement entered into force on November 4, 2016, after the required threshold of ratifications and emissions coverage was reached.