Hot Cities travels the world from Lagos to Los Angeles, from Shanghai to Surat, from Dhaka to Durban to analyse one of the significant threats facing the planet.

Talking to the experts, the politicians and some of the millions of new migrants to the world’s biggest cities, the series assesses not just the threat from climate change but our response.

In 2008 the world reached an important milestone when, for the first time in history, more people lived in cities than the countryside. Homo sapiens had become homo urbanus.

All this has led to a vicious circle. Cities are one of the big drivers of climate change. As cities get even bigger, they drive climate change even harder. And that makes many of these massive urban areas more vulnerable to rising sea levels, violent storms and dramatic changes in temperature.

This December the most important climate change conference in over a decade is being held Copenhagen, where world leaders and their advisors must hammer out a blueprint for survival. Hot Cities shows how important their decisions will be.

Los Angeles is one of the most polluting cities in the world thanks largely to its love affair with the car. It is a city built on consumption. Each person produces around 20 tonnes of emissions per year – twice as much as anyone else.

Historically, Los Angeles – and the rest of America – has been one of the worst climate change offenders. Now they are about to reap what has been sown.

In LA there has been a big increase in wildfires, water supplies are under threat, rising sea levels could have a massive impact on LA’s huge port and destroy thousands of homes.

Hot Cities goes to LA just as the city launches its adaptation strategy. Already LA, and California, have been looking at ways of reducing their huge energy consumption by investing in electric cars and solar panels.

So how will LA adapt to an increasingly hostile environment? And will it any of it be helpful to the developing cities around the world who are bearing the brunt of LA’s profligate carbon past?