If the climate warms more than 3.6 degrees Fahrenheit, we're in a whole lot of trouble. Join CNN's John D. Sutter in a year-long exploration of this important, little-known number. What will the world look like if we cross the 3.6-degree mark? How can we avoid that? And where did this number come from in the first place? We want you to be involved in the coverage -- voting on the stories Sutter will pursue. The project will continue through December 2015. Expect two-ish updates per month.
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