In his first address on the issue, Mr Ban said environmental changes because of climate change were likely to become a major driver of future war and conflicts. He urged the US – the world’s biggest emitted of CO2 – to take the lead in fighting global warming.

Mr Ban said he would focus on the issue in talks with leaders of the G8 group of industrialised nations in June. The UN is also due to hold a conference on climate change in Bali in December.

Speaking to schoolchildren at a UN conference in New York, Mr Ban said his generation had been “somewhat careless” with the planet but that he was hopeful that that was changing. “The majority of the United Nations’ work still focuses on preventing and ending conflict,” he said. “But the danger posed by war to all of humanity and to our planet is at least matched by the climate crisis and global warming.”

Maybe Mr Ban should ban Bush from office…