The natural history broadcaster told the COP26 climate summit that the motivation for tackling climate change should “not be fear, but hope.”
He said: “It comes down to this. The people alive now or the generation to come will look at this conference and consider one thing – did that number stop rising and start to drop as a result of commitments made here.
“There’s every reason to believe that the answer can be yes.
“If, working apart, we are a force powerful enough to destabilise our planet, surely working together we are powerful enough to save it.”
He told delegates: “In my lifetime I’ve witnessed a terrible decline. In yours, you could and should witness a wonderful recovery. That desperate hope… is why the world is looking to you and why you are here.”
He charted carbon emissions throughout human history, which has peaked at 414 parts per million and said that “we are already in trouble”.
He said: “Our burning of fossil fuels, our destruction of nature, our approach to industry, construction and learning, our releasing carbon into the atmosphere – we are already in trouble.
“The stability that we all depend on is breaking.
“This story is one of inequality as well as instability.
“Today those who have done the least to cause this problem are being the hardest hit – ultimately all of us will feel the impacts, some of which are now unavoidable.”
Mr Attenborough asked: “Is this how our story is due to end – a tale of the smartest species doomed by that all too human characteristic of failing to see the bigger picture in pursuit of short-term goals?
“Perhaps the fact that the people affected by climate change are no longer some imagined future generations but young people alive today, perhaps that will give us the impetus we need to rewrite our story, to turn this tragedy into a triumph.”
He added that “we are after all the greatest problem solvers to have ever existed on earth” and that we “now understand the problem” of how to put climate change into reverse.