Paris agreement negotiator Todd Stern attacks premiers who say that decarbonisation programmes are unrealistic and should be slowed down

Political leaders who present themselves as “grownups” while slowing the pace of climate action are pushing the world towards deeper catastrophe, a former US environment chief has warned.

“We are slowed down by those who think of themselves as grownups and believe decarbonisation at the speed the climate community calls for is unrealistic,” said Todd Stern, who served as a special envoy for climate change under Barack Obama, and helped negotiate the 2015 Paris agreement.

“They say that we need to slow down, that what is being proposed [in cuts to greenhouse gas emissions] is unrealistic,” he told the Observer. “You see it a lot in the business world too. It’s really hard [to push for more urgency] because those ‘grownups’ have a lot of influence.”

But Stern said the speed of take-up of renewable energy, its falling cost, and the wealth of low-carbon technology now available were evidence that the world could cut emissions to net zero by 2050. “Obviously it’s difficult – we’re talking about enormous change to the world economy – but we can do it,” he said.