Sir David Attenborough has issued a plea to governments to take action on the environment at the UN Climate Change conference in Paris.
The summit in Paris is the biggest international meeting on the matter in five years. Its aim is to get countries to legally agree to limiting greenhouse gas emissions so the earth's temperature does not rise by more than two degrees Celsius.
Attenborough, making the comments ahead of his new series on the Great Barrier Reef in Australia, also said that the natural wonder of the world may not survive because of our rapidly changing climate.
Prior to his attendance at the conference, Attenborough warned that a complete, cooperative plan should not be expected to arise from the talks:
Speaking to BBC Radio 4, Sir Attenborough, 89, said:
Of course I'm not confident. This is a hideous problem. Never in the history of humanity have all the people of the world got together to deal with one particular problem and agree on what the solution should be.
Never, ever, has that happened before. We shouldn't be surprised that it is difficult. We shouldn't be surprised that there are huge problems.
But it seems to me that the danger is becoming more and more clear to the people attending this conference and that there is, at last, the chance that something might come out of it.
At the summit, Attenborough warned of "disastrous" delays in taking action on climate change, saying that the "alarming" thing was how other issues would "take priority and take world leaders' attention from this urgent problem." Drawing attention to the Great Barrier Reef, the conservationist said:
The reef may not survive the steady erosion, the effect of global warming.
If the temperature rises up by two degrees and the acidity by a measurable amount, lots of species of coral will die out. Quite what happens then is anybody's guess. But it won't be good.
He added that his new series, which he screened in Paris with a leading Queensland scientist, is part of a personal campaign to convince governments to take decisive action to save the reef.