When Trump announced the U.S. withdrawal from the climate agreement in 2017, the move reverberated around the globe. Nearly 200 nations had committed to reducing greenhouse gas emissions under the pact when it was created in 2015, and they had set ambitious targets to keep global temperature rise well below 2°C, and ideally below 1.5°C.

It is a pact that is part of the United Nations Framework Convention on Climate Change, which started in 1992 with the Rio Earth Summit. Technically, the Paris agreement itself is not a treaty so its adoption by America did not require U.S. Senate approval.

President Donald Trump said Monday he will again withdraw the United States from the landmark Paris climate agreement, dealing a blow to worldwide efforts to combat global warming and once again distancing the U.S. from its closest allies.