You can't solve climate change with one idea, but what about 39? Tom Heap presents four more carbon-busting ideas from the satellite pollution detectors high above us to the green fertiliser working its magic deep in the soil. He's joined by the climate scientist Tamsin Edwards to crunch the numbers and by the film star and influential environmentalist Arnold Schwarzenegger who chooses his favourite ideas from the series.

Producer: Alasdair Cross
Researcher: Sarah Goodman

Produced in association with the Royal Geographical Society Show less