Bloomberg is perhaps best known as the Mayor of New York for much of the naughties, and a major businessman and philanthropist aside from his political work (Forbes puts his net worth at $33 billion).

With a background as a Democrat, he switched to the Republicans in 2001 and has been independent since 2007. Bloomberg has been continually open in his belief that global warming is a reality and requires action, and that cities can play a key role in driving such change at a local level. He was chair of the C40 network of cities from 2010 to 2013 and was appointed UN Special Envoy for Cities and Climate Change.

With mayors increasingly seen as playing a driving role in global action on climate change, expect to see more from him. We can expect Bloomberg to be a key voice in how the climate debate plays out in US politics as well as a voice for and within business.