1. After not doing anything about it for decades, China and the U.S. have agreed to tackle a big problem.
The two countries are the world's biggest producers of the greenhouse gas CO2. They signed an agreement to cut CO2 and other emissions that cause climate change.
Here's the tweet from the White House:
2. This is the first-ever pledge like this from China, and it's ambitious — to get 20% of its energy from non-greenhouse-gas-emitting sources by 2030. Here's the fact sheet from the White House with a few more details.
3. Here in the U.S., lots of politicians have pointed to China as the reason the U.S. should not sign climate treaties. What will opponents of climate change action use as an excuse now? Check out this spot-on video from Climate Desk of what the excuses sound like:
4. The agreement means a lot of support for ongoing U.N. climate talks aimed at a worldwide deal on lowering emissions set for Paris 2015.