Fifteen-year-old Swedish activist Greta Thunberg has spoken at the COP24 summit.
A Swedish teenager who inspired students around the world to walk out of their classrooms over climate change inaction has slammed leaders at a major UN summit.
Fifteen-year-old Greta Thunberg travelled to Katowice, Poland, for the COP24 talks and delivered a speech on Monday to UN leader António Guterres and other decision-makers at the conference.
"We are facing an existential threat and there is no time to continue down this road of madness ... Our political leaders have failed us," Ms Thunberg said.
Ms Thunberg has made headlines in Sweden for leaving school each Friday and sitting outside parliament to urge leaders to do more to tackle climate change.
Her activism inspired young people in other countries to take similar action, including in Australia. On Friday, thousands of students followed Ms Thunberg's example and downed books.
"Why should I be studying for a future that soon may be no more, when no one is doing anything to save that future?
"And what is the point of learning facts when the most important facts clearly means nothing to our society?" she told COP24.
"So we have not come here to beg the world leaders to care for our future. They have ignored us in the past and they will ignore us again.
"We have come here to let them know that change is coming whether they like it or not. The people will rise to the challenge. And since our leaders are behaving like children, we will have to take the responsibility they should have taken long ago."
After the speech, she was asked by the press what she thought of the politicians who were not in attendance.
"I think they are very irresponsible ... In the future we will look back, and we will either laugh at them or we will hate them," she said.
Scott Morrison, Donald Trump and Angela Merkel are just some of the leaders who are not attending.
Nearly 200 nations are gathered in Poland this week for the COP24 summit, where they must agree on a universal rulebook to make good on the promises they made in the 2015 Paris climate deal.
One of the key disputes is finance.
Under the Paris agreement, richer nations - responsible for the majority of historic greenhouse gas emissions - are expected to contribute funding that developing nations can access to make their economies greener.