Cheltenham, England — British naturalist David Attenborough said on Saturday he was hopeful that the United States would return to an international climate deal to tackle global warning as denying climate change and its impacts would be "catastrophic".
Speaking at the Cheltenham Literature Festival in southwest England, Attenborough said it had been a "tragedy" that U.S. President Donald Trump decided last year to quit the 2015 Paris climate agreement and promote the U.S. fossil fuel industry.
Attenborough, whose documentaries such as "Planet Earth" and "Blue Planet" have sparked public concern over population growth and plastic use, said the scientific facts about climate change were "simply incontrovertible".
"I'm optimistic enough to think that actually the Americans won't withdraw as much as all that," said Attenborough, 92, Britain's much-loved face of nature and conservation.
"As time goes by, the American people themselves will demand that their government goes back on that and agrees to join the rest of the nations of the world in trying to deal with the huge problems that face us all."
He said the signing of the Paris climate agreement in 2015 by nearly 200 nations, to limit the global average temperature rise, had made those involved feel they were "walking on air".
"It was a marvellous moment and feeling that humanity was making a step forward and to have one of the most important signatories then to say 'no, we're going to withdraw' was desperate," he said.
Attenborough's comments came as top climate scientists meeting in South Korea approved a United Nations report to assess whether global temperatures can be kept in check this century to prevent the most damaging effects of global warming.
On Monday, the Intergovernmental Panel on Climate Change will release the report outlining ways the world can limit global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels.
Attenborough said the natural world could offer a reprieve at a time of political uncertainty with Britain's decision to withdraw from the European Union and the election of Trump.
"In these times, when we're as worried as we are about what's happening in the world about America, about Brexit, about all these other things, I think natural history programmes are responsible and show you the natural world as it is," he said.
The "Blue Planet II" series, which focused on life under water, was the most watched television programme in Britain of 2017, according to the BBC, reaching about 14 million people.
On Thursday, the BBC announced Attenborough would front a new nature documentary series entitled "Dynasties" filmed over four years that would focus on five endangered species including penguins, chimpanzees and tigers.
"I think people have caught on to natural history programmes because they're beautiful, new, they're not trying to sell you anything, they're not trying to give you a political philosophy and above all they're true," he said.
Reporting by Adela Suliman; editing by Belinda Goldsmith.