A ban on selling new petrol, diesel or hybrid cars in the UK will be brought forward from 2040 to 2035, under new government plans.
The change comes after experts said 2040 would be too late if the UK wants to achieve its target of emitting virtually zero carbon by 2050.
Boris Johnson unveiled the policy as part of a launch event for a United Nations climate summit in November.
He said 2020 would be a “defining year of climate action” for the planet.
The summit, known as COP26, is being hosted in Glasgow. It is an annual UN-led gathering set up to assess progress on tackling climate change.
Sir David Attenborough said at the launch event at London’s Science Museum that he was looking forward to COP26 and found it “encouraging” that the UK government was launching a “year of climate action”.
“The longer we leave it… the worse it is going to get,” he said.
“So now is the moment. It is up to us to organise the nations of the world to do something about it.”