John D. Sutter is a columnist for CNN who focuses on climate change and social justice. Follow him on Snapchat, Twitter and Facebook or subscribe to his email newsletter.

(CNN) US President Donald Trump is expected to decide soon whether to withdraw from the Paris Agreement on climate change, which is the world's promise to end the era of fossil fuels and avoid climate catastrophe.

So ... let's unpack that sentence. Because this sentence -- and, consequently, the United States' involvement in the Paris accord -- could help determine the very fate of the planet.

Here it is, Article 4.11 of the Paris Agreement (Warning, it's boring. But stay with me): "A Party may at any time adjust its existing nationally determined contribution with a view to enhancing its level of ambition, in accordance with guidance adopted by the Conference of the Parties serving as the meeting of the Parties to this Agreement."

And here is my rough translation into human-speak: Any country that signs onto the Paris Agreement has to make a pledge to reduce pollution, called a "nationally determined contribution." The United States, for example, pledged to reduce heat-trapping emissions 26% to 28% below 2005 levels by 2025. Anyway, these pledges are the building blocks of this agreement. The overall goal is to eliminate fossil fuel pollution this century, to avoid sinking low-lying islands, flooding cities like New Orleans and creating the sort of runaway warming that scientists say could lead to mass extinction. Hopefully these pollution reduction pledges will get MORE AMBITIOUS over time. But we're not saying explicitly that they MUST get more ambitious.

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