The climate agreement, championed by President Obama, isn't legally binding, but brought almost every nation in the world together to pledge individual goals to reduce their emissions. Obama said the U.S. would reduce its 2005 emission levels by 26% to 28% by 2025, and Trump's announcement means the country will no longer be striving to hit that mark.
Still, the decision was a huge blow to Obama's climate legacy, climate activists, and pretty much any American who believes climate change is real (it is) and cares about combating man-made factors. It's also a huge blow to women, as they're more likely to die in natural disasters worsened by warming temperatures and usually have less resources to adapt to environmental changes.
Democratic politicians responded to President Trump's decision on Twitter, calling it short-sighted and dangerous.
Obama, who helped negotiate the climate deal, released a statement saying, "The nations that remain in the Paris Agreement will be the nations that reap the benefits in jobs and industries created."
While more moderate Republicans also opposed the decision, GOP leaders praised it.
It's also worth noting that climate change wasn't a major issue in the 2016 election, and Trump wasn't asked about it during a presidential debate.
People immediately began looking to the future, theorizing about what this decision will mean for 2020.
That is three whole years away, but at least someone found a silver lining.