The conservationist is serving in the "People's Seat" during the conference, a role in which he will present comments from members of the public affected by climate change to the dignitaries and officials present at the summit.
As part of COP24, Attenborough was speaking from the "People's Seat": an effort to give a voice to the billions of citizens who aren't in attendance at the United Nations summit - but whose continued existence on the planet depends on the decisions made over the next fortnight by the delegates invited.
"Right now, we are facing a man-made disaster of global scale", Attenborough began.
The documentary maker warned it could lead to the collapse of civilisations and the extinction of "much of the natural world". Their message is clear: "Time is running out", Attenborough said Monday.
Fiji's prime minister, Frank Bainimarama, who presided over last year's United Nations climate summit, said the "just transition" proposal should not just consider the fate of fossil-fuel workers but all people around the world whose lives were affected by climate change.
"The decisions we take now will define the next century", Mr Bruton said.
Of the 10 countries in the world considered most threatened by climate change, seven are in Africa - Central African Republic, Chad, Eritrea, Ethiopia, Nigeria, Sierra Leone and South Sudan.
The Arc de Triomphe is illuminated in green with the words "Paris Agreement is Done", to celebrate the Paris U.N. COP21 Climate Change agreement in Paris, France, Nov. 4, 2016. "Let us rise to the challenge and finish the work the world demands of us".
The UN has launched an "ActNow.bot", which helps people discover simple everyday actions they can take to tackle climate change.
Thousands of people marched in Brussels on Sunday to "Claim the Climate" in a demonstration ahead of the COP24 climate conference.
UN Secretary-General António Guterres has warned that the world is in "deep trouble" due to climate change. He told the delegates that "Climate change is running faster than we are and we must catch up sooner rather than later before it is too late.For many, people, regions and even countries this is already a matter of life or death".
"Or, God forbid, [we] ignore the irrefutable evidence and become the generation that betrayed humanity", Bainimarama said. "Climate action offers a compelling path to transform our world for the better. This must be powered by multilateral co-operation".
They called for ambitious decisions which are sufficiently detailed and comprehensive to enable the effective operation of the Paris Agreement, secured three years ago in the French capital to curb global warming.
To reach this goal, emissions must be halved from 2010 levels by 2030, Guterres said.
And there needs to be progress on the goal of mobilising $100bn (€88bn) a year for poorer countries to drive clean growth, they urged.
The World Bank has announced it is doubling investments in climate action with $200bn (€176bn) for 2021-2025, including $50bn (€44bn) towards helping countries adapt to the impacts of global warming.
The vast majority of the scientific community agrees that climate change is happening, though notable holdouts-including President Donald Trump-have frustrated global efforts to address the crisis and squandered precious time and resources that could have been used to limit carbon emissions.