BBC Radio Four presents 39 ideas to relieve the stress that climate change is exerting on the planet.

Trees soak up carbon dioxide, trees store carbon dioxide. So why not build with wood instead of concrete and steel? The usual reason is strength, but Dr Michael Ramage at Cambridge University has what he thinks is the answer- cross-laminated timber. It's strong enough to build a skyscraper and replaces lots of that carbon from conventional building. Tom Heap and Dr Tamsin Edwards take a look at the global possibilities of cities built of wood.

Producer : Alasdair Cross

Researcher: Sarah Goodman

Produced in association with the Royal Geographical Society. Special thanks for this episode to Dr Harry Kennard from University College London.