CNN Opinion columnist John D. Sutter is reporting on a tiny number -- 2 degrees -- that may have a huge effect on the future. You can subscribe to the "2 degrees" newsletter or follow him on Facebook, Twitter and Instagram. He's jdsutter on Snapchat. You can shape this coverage.
Le Bourget, France (CNN)If you've looked at this website much in 2015, you've probably noticed I've been writing something over and over and over: 2 degrees Celsius is the danger zone for global warming.