President Donald Trump on his first day in office again withdrew the U.S. from a landmark global pact to fight climate change. So what is the Paris Agreement? And what happens to it now?

Trump's executive order called for an immediate withdrawal from the Paris Agreement. The Agreement requires one year notice, but there's room for interpretation.

The Paris agreement is a mostly voluntary climate pact originally written to both try to reduce warming and withstand the changing political winds in the U.S.