One of President Trump’s first executive orders withdraws the U.S. from the Paris climate agreement. These graphics show why the pact is crucial to curbing the worst effects of global warming

The Paris agreement is complex and works in a slow bureaucratic manner. It’s a mostly voluntary climate pact originally written in ways that would both try to reduce a worsening climate change problem and withstand the changing political winds in the United States.

Trump signed an executive order that begins the process of withdrawing from the Paris Climate Agreement, which he also did during his first term.