Sir David Attenborough is calling on global leaders to step up their actions to curb climate change, saying that they are in denial about the dangers it poses despite the overwhelming evidence about its risks.
The TV naturalist said those who wield power need to use it: "Wherever you look there are huge risks.
"The awful thing is that people in authority and power deny that, when the evidence is overwhelming and they deny it because it's easier to deny it - much easier to deny it's a problem and say 'we don't care'," Sir David said.
In terms of climate change, "we won't do enough and no one can do enough, because it's a very major, serious problem facing humanity; but at the same time it would be silly to minimise the size of the problem", he told Sky News.
Later this year, a crucial UN climate summit will be held, at which world leaders have pledged to agree to tough cuts in their carbon emissions, to ensure the increase in global warming does not exceed 2°C - beyond which its consequences become increasingly devastating.
Although that meeting is not scheduled to take place until December, the scale of the task ahead is huge and world leaders are already working towards the summit.
However Sir David is concerned that, despite the increasingly obvious scale of the threat climate change poses, leaders are not taking the matter as seriously as they should.
"Never in the history of humanity in the last 10 million years have all human beings got together to face one danger that threatens us - never.
"It's a big ask, but the penalty of not taking any notice is huge," he said.
Sir David's comments come two days after a separate warning - on the dangers posed by the booming human population.
"It's desperately difficult, the dangers are apparent to anybody," he told The Independent.
"We can't go on increasing at the rate human beings are increasing forever, because the Earth is finite and you can't put infinity into something that is finite.
"So if we don't do something about it - the natural world that is - we will starve," Sir David said.
Last month, a newly discovered species of beetle was named Trigonopterus attenboroughi, in honour of Sir David Attenborough. Alexander Riedel, the researcher who discovered the 2.14mm-long species, said he called the beetle after Sir David because he enjoyed watching his television programmes so much as a child.
This is not the first time he has had a species named after him. In 2009, a flesh-eating pitcher plant, so large that it can swallow and devour rats whole, was discovered on Mount Victoria in the Philippines and named Nepenthes attenboroughii.
Two years later, a one-millimetre species of goblin spider was discovered on Horn Island, off the coast of Australia, and named Prethopalpus attenboroughi, or Attenborough's goblin spider.
- The Independent