You’ll probably hear the term “net-zero emissions” a lot over the coming weeks as government leaders and CEOs under pressure talk about how they’ll reduce their countries’ or businesses’ impact on climate change. Amazon, for example, just announced that more than 200 companies have now joined The Climate Pledge, committing to reach net-zero emissions by 2040.

But what does net-zero emissions actually mean?

“Zero emissions”—without the “net” caveat—means emitting no greenhouse gases.

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