Tom Heap and Helen Czerski meet the people with fresh ideas to combat rising sea levels, from Enfield to Indonesia.

Average sea levels across the world are rising fast. That puts 570 cities with a combined population of 800 million people at significant threat of inundation. Add in the impact of extreme rainfall events and you have a huge slice of our urban planet that needs protection from flooding. Tom and Helen are joined by Professor Richard Dawson of Newcastle University who considers the engineering solutions available, from huge chunks of concrete and steel to the clever use of parks and gardens that can slow down the flow of water into the streets.

Emma Howard Boyd, former chair of the Environment Agency, tells them about her London Climate Resilience Review which shines a light on the urgent need to raise the city's embankments and suggests some quirkier options. Could the 160,000 large holes that are dug ever year in London be repurposed as emergency water buffers?

Helen visits New Orleans, 19 years after one of the world's most disastrous urban floods, to meet Dana Eness who leads the Front Yard Initiative which helps city residents floodproof their homes with native flower gardens and rainwater butts. And journalist, Peter Hadfield, discusses his visit to Jakarta, the capital of Indonesia that's sinking fast. There are ambitious plans for new sea defences linked by artificial Dubai-style luxury islands, but the national government has decided to abandon the city in favour of a new capital over 1000km away.

Producer: Alasdair Cross

Assistant Producer: Toby Field