Video report by ITV News Correspondent Martha Fairlie
The world is approaching the "point of no return" if politicians do not act to halt the climate crisis, the UN Secretary-General warned on Sunday.
Antonio Guterres said global efforts against the impact of rising temperatures - including more extreme weather - had been been “utterly inadequate," blaming a lack of "political will".
Speaking a day before the start of the two-week long UN Climate Change Conference (COP25) in Madrid, the UN chief said the effects of the climate crisis was already being felt around the world, with dramatic consequences for humans and other species.
He noted the world had the scientific knowledge and the technical means to limit global warming, while growing demands from citizens, particularly young people, had shown a widespread desire for climate action.
“The point of no return is no longer over the horizon,” Mr Guterres told reporters in the Spanish capital. “It is in sight and hurtling toward us.”
Delegates from almost 200 countries will try to put the finishing touches on the rules governing the 2015 Paris climate accord at the meeting, including how to create functioning international emissions trading systems and compensate poor countries for losses they suffer from rising sea levels and other consequences of climate change.
Mr Guterres cited mounting scientific evidence for the impact man-made emissions of greenhouse gases were already having on the planet, including record temperatures and melting polar ice.
But he insisted his message was “one of hope, not of despair. Our war against nature must stop and we know that that is possible.”
Countries agreed in Paris four years ago to limit global warming to well below two degrees Celsius (3.6 Fahrenheit), ideally 1.5C (2.7F) by the end of the century compared with pre-industrial times. Already, average temperatures have increased by about 1C, leaving little room for the more ambitious target to be met
Mr Guterres said: "What is still lacking is political will,” he said.
“Political will to put a price on carbon. Political will to stop subsidies on fossil fuels. Political will to stop building coal power plants from 2020 onwards. Political will to shift taxation from income to carbon. Taxing pollution instead of people.”
Mr Guterres noted some 70 countries - many of them among the most vulnerable to climate change - have pledged to stop emitting more greenhouse gases by 2050.
“But we also see clearly that the world’s largest emitters are not pulling their weight. And without them, our goal is unreachable,” he said.
The UN chief said he hoped the Madrid meeting would prompt governments to make more ambitious pledges ahead of a deadline to do so next year.
He also said creating a worldwide market for emissions, which is a key element of the sixth article of the Paris accord, remained one of the most contentious issues for negotiators.
Mr Guterres also announced outgoing Bank of England governor Mark Carney would become his new special envoy on “climate action and climate finance” from next year.
Organisers expect around 29,000 visitors, including 50 heads of state and government for Monday’s opening, as well as scientists, seasoned negotiators and activists during the two-week meeting.
Some of the world’s largest carbon emitters - the United States, China and India - will be represented by ministers or lower-level officials.
The US administration of President Donald Trump, which has announced the intention to withdraw from the Paris agreement, is represented by Marcia Bernicat, Principal Deputy Assistant Secretary of State for Oceans and International Environmental and Scientific Affairs. House Speaker Nancy Pelosi is leading a delegation of Democratic lawmakers to the talks.