Former Mayor of New York Michael Bloomberg is taking up the role of Special Envoy for Cities and Climate Change at the UN.

The title of Special Envoy is usually reserved for former heads of state or government.

He will assist the UN Secretary-General Ban Ki-Moon to prod cities into combating climate change.

Mr Bloomberg said: “Cities account for more than 70% of global greenhouse gas emissions and two-thirds of the world’s energy use today and their total population is projected to double by 2050 – so the steps they take now to combat climate change will have a major impact on the future of our planet.”

As Mayor of New York, he spearheaded PlaNYC which brought 25 city agencies together and helped cut the Big Apple’s carbon footprint by 19% since 2005.