UPDATE 5:39 p.m. ET: 

President Obama delivered an impassioned speech today praising diplomats at the UN climate summit for coming to an agreement. "Make no mistake—the Paris agreement establishes the enduring framework the world needs to solve the climate crisis," he said. "This agreement is ambitious, with every nation setting and committing their own specific targets. As technology advances, this agreement allows progress to pave the way for even more ambitious targets over time. This agreement represents the best chance we've had to save the one planet we've got." 

See below for the original story published on 12/12/15.

It took several months of record global heat, hundreds of air pollution warnings, two decades of talks, and the threat of more than 6 million premature deaths a year, but the world's leaders have finally decided to do something about climate change. This evening in Paris, leaders from 195 countries around the world reached a groundbreaking deal to combat climate change. The deal comes at the end of the two-week UN climate summit in Paris and is, in effect, a pledge to stop emitting greenhouse gas. There was much self-congratulatory applause.

According to The Guardian, the key points in this historic deal (in plain English) are:

  • A pledge to keep temperatures below 1.5 degrees Celsius (we've already hit a global increase of 1 degree Celsius); after 1.5 Celsius, we could start seeing disastrous and irreversible effects on the world's climate.
  • A goal of net zero emissions between 2050 and 2100—the UN climate science panel says emissions must be cut to zero before 2070 to avoid serious damage.
  • A promise to provide funds ($100 billion annually) to developing countries to help them transition into operating more sustainably.
  • Every five years, countries will have to submit a review to make sure they're keeping good on their promises to lower emissions. 

Naturally, U.S. politicians used the deal as an invitation to offer their own opinions on climate change.

But in sum, today was a good day for global politics and for the planet. The Paris Agreement appears to be comprehensive, reasonable, and flexible—let's hope our combined efforts can reverse climate change before we blow up the planet and have to move to Mars.