As of April 12, 2017, 144 countries, including the US, had ratified the Doha Amendment to the Kyoto Protocol.

Doha Amendment

An amendment to the Kyoto Protocol that includes new carbon emission reduction commitments for participating countries and was adopted in Doha, Qatar.

Kyoto Protocol

An international agreement linked to the United Nations Framework Convention on Climate Change that commits its parties to reduce greenhouse gas emissions, based on the scientific consensus that global warming is occurring and that human-made CO2 emissions are significant contributors.

Ratified

Formally approved or confirmed, often referring to the process by which legislation or constitutional amendments become valid.