Yesterday, President Donald Trump announced that he plans to pull out of and potentially renegotiate the Paris climate agreement. The 2015 agreement commits the US and 195 other countries to keeping global temperatures "well below" 2C above pre-industrial levels by limiting human carbon emissions.
The United States is the second biggest carbon emitter in the world, and the UN World Meteorological Organisation warned that by pulling out, the US could add 0.3C to global temperatures by the end of the century.
The United States joins Syria and Nicaragua as the only three countries that aren't part of the agreement. Nicaragua refused to join because they believe that the agreement doesn't go far enough to protect the environment, while Syria has been ravaged by civil war.