Removing carbon dioxide from our atmosphere - and stopping it getting up there in the first place - is becoming increasingly urgent if we want to prevent catastrophic climate change. There are some seriously high tech machines being developed to try and tackle this problem, but could an equally powerful solution be found in the dirt under our feet? Prompted by New Zealand farmer and CrowdScience listener Kem, we dig deep to see how effectively plants and soils soak up CO2 from the air; and what that means for how we should farm the land around the world. And we visit a Scottish forest to find out how the ancient art of making charcoal is staging a comeback in the fight against climate change.

Presenter: Marnie Chesterton

Producer: Cathy Edwards for BBC World Service

(Photo: A young plant in soil, in the morning light. Credit: Getty Images)