His name is Bill de Blasio, he is 51 years old and before his election as mayor of New York he was the city's public advocate, a role similar to our own ombudsman — a figure whose duty is to ensure that citizens' rights are upheld.

Today (in practice from 1 January 2014) he enters New York City Hall as mayor in place of Michael Bloomberg, having defeated his Republican challenger Joe Lhota by a margin of almost 49 percentage points (73.3% – 24.3%) in the election held on Tuesday 5 November. Such a sweeping victory had not been seen since 1985, when Ed Koch won by a similarly large margin.

De Blasio is a Democrat and during the primaries he was one of the most progressive candidates in the race. During the campaign he placed great emphasis on the need to reduce inequality between rich and poor and on the lack of integration among residents of different neighbourhoods — areas increasingly inhabited by people from a single social class.

What received little attention is climate change, perhaps because de Blasio considers it a subject that cannot be separated from the shared goal of steering the city towards a future of "progress". The effects of global warming are already well known and we witnessed them with Hurricane Sandy, a year ago, when the lower-lying neighbourhoods were submerged for days.

New York is made up of a series of small islands and has nearly 840 kilometres of coastline. These features make it one of the cities most threatened by rising sea levels caused by the melting of ice. In addition, the increase in ocean surface temperatures is causing storms that are ever more powerful and frequent.

An insightful analysis of what Bill de Blasio will have to face in the coming years was published by the online magazine Grist: "If he wants to help all New Yorkers thrive, he will have to take the problem of climate change as seriously as he has taken the problem of economic inequality. Reducing the city's greenhouse gas emissions and preparing neighbourhoods for storms and rising sea levels is a moral imperative for achieving the progress he has described, no less important than housing the homeless, promoting social mobility or welcoming migrants."

These are interconnected issues that cannot be addressed in isolation. Not least because many New Yorkers who find themselves in poverty, who have been left without homes or jobs, are in that situation precisely as a result of the devastation wrought by Sandy. For all these reasons, climate change is now the greatest challenge facing Bill de Blasio.