According to development economist Jeffrey Sachs the fight against climate change won’t cost us more than 1% of global income per year, a sum that the world can afford.

“If we look seriously at mitigation, it is not too expensive,” he told a conference in Geneva on the humanitarian impact of climate change.”

“If we invested around $700 billion per year, we would be able to create a sustainable energy system.”

“The United States spent just $3 billion on sustainable energy last year - equal to 36 hours of spending by the Pentagon on defence, according to Sachs, who is director of the Earth Institute at New York’s Columbia University.”

Jeffrey Sachs also criticised governments around the world for failing to live up to their promises to provide development aid and relief to poor people already affected by the effects of climate change, saying “how the rich world leaves the poor world to die is the biggest mistake on the planet.”