How scientists test whether humans are causing our extreme weather

An emerging field of climate science that analyzes extreme weather events is behind the assertion that the unprecedented heat waves sweeping the globe are a result of human-induced climate change.

Extreme event attribution examines the human fingerprint on weather-related disasters by comparing our current world — and its growing amount of weather anomalies — to an idealized one, where the human influence on climate never happened.

To do that, researchers run computer programs known as climate models that simulate weather patterns over time, not unlike those used for a local seven-day forecast. But they re-create the weather over decades or centuries, rather than hours or days.

“The really cool thing about climate models is that you have a world in a computer, and you can do experiments on it,” said Andrew Pershing, vice president of science at the research nonprofit Climate Central. “And you can literally do the experiment of what would this world look like if global warming never happened.”

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