The UN Climate Change Conference COP25 aims to put the finishing touches to the rules governing the 2015 Paris accord.
Delegates from almost 200 countries have begun on Monday a two-week international climate conference in Madrid that seeks to step up efforts to stop global warming.
The COP25 chair warned at the opening that those refusing to adjust to the planet’s rising temperatures “will be on the wrong side of history.”
Chile’s environment minister, Carolina Schmidt, said that the December 2-13 meeting in Madrid needs to lay the groundwork for moving toward carbon-neutral economies while being sensitive to the poorest and those most vulnerable to rising temperatures — something that policymakers have termed “just transition.”
“Those who don't want to see it will be on the wrong side of history,” she said, calling on governments to make more ambitious pledges to reduce emissions of greenhouse gases ahead of a deadline to do so next year.
Confronted with a climate crisis threatening civilisation itself, humanity must choose between hope and surrender, UN chief Antonio Guterres told the opening plenary of a UN climate conference on Monday.
"One is the path of surrender, where we have sleepwalked past the point of no return, jeopardising the health and safety of everyone on this planet," Guterres said.
"Do we really want to be remembered as the generation that buried its head in the sand, that fiddled while the planet burned?"
In a separate forum moments earlier, US Congressional leader Nancy Pelosi told the "COP25" conference that the world could still count on the United States despite President Donald Trump's decision to pull out of the Paris Agreement.
States and cities home to two-thirds of the US population are committed to the targets set by the 2015 agreement, as are all the Democratic candidates for president according to the US research groups.
"We're here to say to all of you, on behalf of the House of Representatives and the Congress of the United States, we're still in it, we're still in it," Pelosi said to applause at a forum of heads of state from climate-vulnerable nations.
Leading the 15-strong Congressional delegation, Pelosi came to Madrid even as her colleagues in the House consider articles of impeachment against Trump.
Trump has dismissed global warming as a hoax, and dismantled many of the climate and environmental protection policies set in place by his predecessor Barack Obama.
Last month Trump gave formal notice of the US withdrawal from the 196-nation Paris climate treaty, which calls for capping global warming at well below two degrees Celsius (3.6 degrees Fahrenheit), and 1.5C if possible.
The summit, which moved to the Spanish capital after Chile had to pull out amid anti-government protests, aims to put the finishing touches to the rules governing the 2015 Paris accord.
That involves creating a functioning international emissions-trading system and compensating poor countries for losses they suffer from rising sea levels and other consequences of climate change.
“We have a common challenge but with differentiated needs and urgencies, which we can only overcome if we work together,” said Schmidt as Chile took over the chairing of the meeting from Poland.
Countries agreed in Paris four years ago to limit global heating to well below 2 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.
Organisers expect around 29,000 visitors to the meeting, including around 50 heads of state and government for Monday’s opening session.
Except for the European Union’s newly sworn-in leadership, which was due to begin a five-year term by paying a visit to the summit, the rest of the world’s largest carbon emitters — the US, China and India — are sending ministerial or lower-level officials to the meeting.