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?

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.

President Donald Trump once again withdrew the United States from the Paris climate deal on Monday, removing the world's biggest historic emitter from global efforts to fight climate change for the second time in a decade.