Veteran British nature-documentary broadcaster David Attenborough warned that both civilisation and the natural world are on the brink of collapse, as world leaders prepare to gather in Poland for the UN climate summit. The 92-year-old naturalist addressed the delegates from more than 200 nations in Katowice, as teams work to find ways to ensure implementation of the historic 2016 Paris Climate agreement that seeks to slash global greenhouse emissions from 2020. "Right now, we're facing a man-made disaster of a global scale – our greatest threat in thousands of years, climate change. If we don't take action, the collapse of our civilisations and the extinction of much of the natural world is on the horizon. The UN provides a unique platform that can unite the whole world and as the Paris agreement proved, we can make real change happen," Mr Attenborough said. “The world’s people have spoken – their message is clear they want you, the decision makers, to act now. They are behind you, along with civil society [who are] represented here today, supporting you in making tough decisions, but also willing to make sacrifices in their daily lives,” he added. Mr Attenborough has been leading a campaign to engage ordinary people with the COP24 conference, leading a campaign called #TakeYourSeats, calling on members of the public to submit comments, questions, pictures and videos, as well as a series of global opinion polls curated in to 'the people's address" shown as part of his presentation. At the opening of the summit on Monday, UN Secretary-General Antonio Guterres said the world faced a stark choice between life and death. “Climate change is running faster than we are and we must catch up sooner rather than later before it is too late”, he said. "For many people, regions, even countries, this is already a matter of life and death. It is hard to overstate the urgency of our situation.” He said that the World Meteorological Organisation has measured the 20 warmest years on record in the past 22 years, with four of these in the past four years. The concentration of carbon dioxide is the highest it has been in three million years and emissions continue to grow. <strong>______________</strong> <strong>Read more: </strong> <strong><a href="https://www.thenational.ae/world/europe/at-risk-nations-to-make-case-at-un-climate-summit-1.798655">At-risk nations to make </a></strong><strong><a href="https://www.thenational.ae/world/europe/at-risk-nations-to-make-case-at-un-climate-summit-1.798655">case</a></strong><strong><a href="https://www.thenational.ae/world/europe/at-risk-nations-to-make-case-at-un-climate-summit-1.798655"> at UN climate summit</a></strong> <strong>Opinion: <a href="https://www.thenational.ae/opinion/comment/climate-change-denial-is-just-the-latest-example-of-trump-s-post-truth-presidency-1.798696">Climate change denial is just the latest example of Trump's post-truth presidency</a></strong> <strong><a href="https://www.thenational.ae/world/europe/french-pm-to-skip-climate-meeting-to-focus-on-riot-1.798054">French PM to skip climate meeting to focus on riot</a></strong> <strong>______________</strong> The 2016 Paris climate talks (COP21) saw almost 200 nations commit to a variety of national goals designed to keep global temperatures "well below" 2°C above pre-industrial levels and try to limit to them to 1.5°C. Experts warn that failure to meet this target will result in massive environmental change and potentially irreversible habitat destruction. While the aim of the agreement is to keep global average temperatures to less than a 2°C riseby the end of the century, the latest research indicates that threshold could be hit by 2030 and surpassed soon after without dramatic changes. US President Donald Trump pulled out of the deal last year, stating his opinion that it was "an agreement that disadvantages the United States to the exclusive benefit of other countries".