In December 2015, 195 countries made history when they agreed to the world's most ambitious pact to limit carbon emissions.
The Paris agreement, so named because that's where the COP21 meeting of nations took place, was a landmark accord setting the world on course to keep global surface temperatures from rising 1.5 degrees Celsius above where they were before the Industrial Revolution.
Climate experts warn that an increase of more than 2 degrees Celsius could bring about irreversible consequences, including unpredictable superstorms and crippling heat waves.
On Thursday, President Donald Trump announced he was pulling United States out of the agreement, which means the US would join Syria and Nicaragua as the only nations that did not agree to the pact. Even Palestine and North Korea signed it.
Syria, ravaged by civil war, didn't participate, while Nicaragua didn't sign the agreement because it didn't go far enough. The Latin American country's climate envoy Paul Oquist said Nicaragua was "not able to support the consensus."
Nearly every country agreed to the overall accord laying out a framework for countries to adopt clean energy and phase out fossil fuels. Each country also submitted a climate-action plan laying out how it would achieve these goals.
Former President Barack Obama ratified the US's adoption of the agreement in September 2016, but he didn't submit it to Congress for approval. That's how Trump can "cancel" the US's pledge — it was a presidential action.
Of the 195 that signed on, 147 (if you include the US) have since ratified the accord. Here they are:
