The idea of smart cities has become the latest hot topic in the tech industry. By 2050, it is estimated that 70% of the world's population will live in cities. However, cities cover just 2% of the Earth's surface yet consume about 75% of the world's resources. Given that more of the world's population now live in cities than in rural areas, it's clear they are key to tackling climate change and reducing resource use. 

Here to tell us more about smart cities and how we can develop more of them is Sir Edward Lister from the Mayor of London's office, Deputy Mayor of Policy and Planning