Carbon dioxide is a molecule so important it has shaped life on Earth for billions of years. Without it, there would be no plants, no oceans, no people. But now, after centuries of burning coal, oil and gas, it's in the atmosphere at levels that alarm scientists.

In this episode of The Climate Question, Graihagh Jackson speaks to Peter Brannen, science journalist and author of The Story of CO2 is the Story of Everything, and Esme Stallard, BBC climate and science reporter.

They explore what makes this tiny molecule so powerful, how it has driven ice ages and mass extinctions, why the story of CO2 is the story of human progress — and what might come next.

Host: Graihagh Jackson Production Team: Diane Richardson, Nik Sindle, Graihagh Jackson, Grace Braddock Sound Mix: Tom Brignell and Ben Andrews Editor: Simon Watts

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