What We Know

Based on the evidence, about 97% of climate scientists agree that human-caused climate change is happening.

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Hear From the Scientists

As experts in climate science, it's our responsibility to tell you what we know. Climate change isn't going to happen; it's already happening.

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Read the Backgrounder

Based on the evidence, about 97% of climate experts have concluded that human-caused climate change is happening. What We Know helps us understand the science behind the realities, risks and response to the climate challenge.

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About the Initiative

Understanding science is our work. Our consensus is that climate change is happening and the risks are real. Learn more about AAAS and the What We Know initiative.

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How We Respond

In 2019, AAAS launched the How We Respond project: a report and multimedia stories highlighting U.S. communities that are actively and effectively responding to climate change.

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Hear first-hand from scientists

Consensus Sense

The AAAS "What We Know" initiative is about sharing what climate experts h...
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Brake 4 Climate

We manage risks every day. We take precautions — like wearing our seat b...
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Alan I. Leshner

We don't need to debate if the climate is changing anymore. Now, what woul...
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Mario Molina

El cambio climático global ya es una realidad. Lo estamos viendo con toda...
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What We Know

Hear From the Scientists

Read the Backgrounder

About the Initiative

How We Respond

Hear first-hand from scientists

Consensus Sense

Brake 4 Climate

Alan I. Leshner

Mario Molina