David Attenborough says climate change 'our greatest threat in thousands of years'

British broadcaster and environmentalist Sir David Attenborough has urged world leaders to take action against climate change, in a rousing speech at a UN meeting.

Sir David has had a long career in documentary making - his recent award-winning project Blue Planet highlighting the impact that pollution has on our oceans.

"Leaders of the world, you must lead," said the environmentalist to a room including two dozen heads of state and government.

"The continuation of our civilisations and the natural world upon which we depend, is in your hands," he said.

He was given a "People's seat" at the two-week UN climate conference in Katowice, Poland, representing the public, and introduced a video compiled from public submissions addressing leaders responses to climate change.

Sir David said climate change was an issue that needed to be addressed urgently.

"Climate change is running faster than we are and we must catch up sooner rather than later before it is too late."

Limits for global warming were agreed upon in the 2015 Paris accord on climate change, and were intended to prevent mass extinction, rising sea levels and extreme weather events.

But the world is currently on track to overshoot these limits greatly.

The goal is to limit global warming to between 1.5 and 2.0 degrees Celsius. In October, the average global temperature difference was 0.86 degrees Celsius above the 20th century average.

The talks in Katowice are part of an effort to outline a set of rules on enforcing action against climate change.

Urgency for solutions to rising global temperatures prompted the talks in Poland to begin a day early, on Sunday delegates from almost 200 nations began debates on how best to target the problem.

The wider political environment surrounding climate change has changed over the past few years, people becoming fed up with lack of action, and Sir David urged that leaders need to stop talking about, and start implementing change.

"The wave of optimism and global co-operation that carried us to and through Paris has now crested, broken and is now tumbling," he said.