KATOWICE, Poland (AP) — As leaders attending the U.N.'s annual climate summit heard fresh warnings about the dire consequences of leaving global warming unchecked, a new issue emerged Monday as a pressing concern: how to persuade millions of workers their industry can't have a future if humanity is to have one.

Hosting the talks in the heart of its coal region of Silesia, Poland tried to set the tone for the two-week meeting by promoting the idea of a "just transition" for miners and other workers facing layoffs as countries adopt alternative energy sources.

"We are trying to save the world from annihilation, but we must do this in a way that those who live with us today in the world have the best possible living conditions," Polish President Andrzej Duda said. "Otherwise they will say, 'We don't want such policy.'"

The issue of a "just transition" isn't restricted to workers in energy industries who might lose their jobs. Many economists argue that ambitious curbs on greenhouse emissions require raising the cost of carbon fuels — one of the measures that triggered large-scale protests in France by motorists feeling the squeeze at the pump.

Scientists say the only way to keep average global temperatures from rising above 1.5 degrees Celsius (2.7 F) by the end of the century is to phase out the use of fossil fuels by 2050. That is the most ambitious goal set in the 2015 Paris agreement, which negotiators from nearly 200 countries have come to Katowice to finalize.

Actor Arnold Schwarzenegger delivers a speech during the opening of COP24 UN Climate Change Conference 2018 in Katowice, Poland, Monday, Dec. 3, 2018.(AP Photo/Czarek Sokolowski)

U.N. Secretary-General Antonio Guterres issued a dramatic appeal to leaders Monday to take the threat of global warming seriously, calling it "the most important issue we face."

UN Secretary General Antonio Guterres delivers a speech WLduring the opening of COP24 UN Climate Change Conference 2018 in Katowice, Poland, Monday, Dec. 3, 2018.(AP Photo/Czarek Sokolowski)

"Even as we witness devastating climate impacts causing havoc across the world, we are still not doing enough, nor moving fast enough, to prevent irreversible and catastrophic climate disruption," Guterres told delegates from almost 200 countries on the second day of talks.

UN Secretary General Antonio Guterres addresses during the opening of COP24 UN Climate Change Conference 2018 in Katowice, Poland, Monday, Dec. 3, 2018. (AP Photo/Czarek Sokolowski)

Famed British naturalist Sir David Attenborough echoed his warnings, telling the gathering that the "collapse of our civilizations and the extinction of much of the natural world is on the horizons" if no urgent action is taking against global warming.

In this photo taken Wednesday, Oct. 3, 2018, a bird flies past as smoke emits from the chimneys of Serbia's main coal-fired power station near Kostolac, Serbia. The COP 24 UN Climate Change Conference is taking place in Katowice, Poland. Negotiators from around the world are meeting for talks on curbing climate change. (AP Photo/Darko Vojinovic)

The 92-year-old TV presenter blamed humans for the "disaster of global scale, our greatest threat in thousands of years."

Leaders and negotiators from almost 200 nations from around the globe listen to speeches during the official opening of the key U.N. climate conference that is to agree on ways of fighting global warming in Katowice, Poland, Monday, Dec. 3, 2018. (AP Photo/Czarek Sokolowski)

Without naming specific countries, Guterres chided the nations most responsible for greenhouse gas emissions for failing to do enough to meet the goals set in Paris.

Swiss Federal President Alain Berset, right, talks to Dutch Prime Minister Mark Rutte, during a bilateral meeting during the COP24 United Nations Climate Change Conference in Katowice, Poland, Monday, Dec. 3, 2018. (Peter Klaunzer/Keystone via AP)

Citing a recent scientific report , the U.N. chief urged governments to aim for net zero emissions by 2050. Net zero emissions mean that any greenhouse gases emitted need to be soaked up by forest or new technologies that can remove carbon from the atmosphere.

FILE- In this July 26, 2011 photo, a melting iceberg floats along a fjord leading away from the edge of the Greenland ice sheet near Nuuk, Greenland. The COP 24 UN Climate Change Conference is taking place in Katowice, Poland. Negotiators from around the world are meeting for talks on curbing climate change. (AP Photo/Brennan Linsley, File)

Such cuts would require a radical overhaul of the global economy. But Guterres said governments should embrace the opportunities of shifting to a "green economy" rather than cling to fossil fuels such as coal, which are blamed for a significant share of man-made greenhouse gas emissions.

In this Nov. 21, 2018 photo smoke billows from chimney stacks of the heating and power plant in Bedzin, near Katowice, Poland. The COP 24 UN Climate Change Conference is taking place in Katowice. Negotiators from around the world are meeting for talks on curbing climate change. (AP Photo/Czarek Sokolowski)

U.S. officials have kept a low profile at the talks so far. President Donald Trump has announced Washington's withdrawal from the Paris accord, saying it's a bad deal for Americans, and repeatedly questioned the science behind climate change.

Poland's President Andrzej Duda addresses representatives of almost 200 nations during a ceremonial opening of the key U.N. climate conference that is to agree on ways of fighting global warming in Katowice, Poland, Monday, Dec. 3, 2018.(AP Photo/Czarek Sokolowski)

By contrast, action film star and former California Governor Arnold Schwarzenegger drew crowds and applause at the U.N. conference Monday for insisting that many in the United States remain committed to the agreement.

Leaders and negotiators from almost 200 nations from around the globe listen to speeches during the official opening of the key U.N. climate conference that is to agree on ways of fighting global warming in Katowice, Poland, Monday, Dec. 3, 2018.(AP Photo/Czarek Sokolowski)

"America is more than just Washington or one leader," he said, calling Trump "meshugge" — Yiddish for "crazy" — for deciding to withdraw from the Paris accord. Schwarzenegger said he wished he could travel back in time — like the cyborg he portrayed in "The Terminator" — to stop fossil fuels from being used.

Prime Minister of Fiji and COP 23 President Frank Bainimarama talks with the President of COP 24 Michal Kurtyka, right, as Polish President Andrzej Duda, left, looks on during the opening of COP24 UN Climate Change Conference 2018 in Katowice, Poland, Monday, Dec. 3, 2018. (AP Photo/Czarek Sokolowski)

The Netherlands, a country with a long history of pumping oil and gas from the ground, is also among the places most at risk from rising sea levels caused by global warming.

World Bank CEO Kristalina Georgieva speaks during the COP24 United Nations Climate Change Conference in Katowice, Poland, Monday, Dec. 3, 2018. (Peter Klaunzer/Keystone via AP)

With millions of people in the Netherlands living in low-lying areas, "you have your evidence and your case in point to make, sure, that you prevent sea levels from rising even further" Dutch Prime Minister Mark Rutte told The Associated Press.

Michal Kurtyka, Polish Deputy Minister of the Environment and President of the COP24, right, talks to Andrzej Duda, President of Poland, left, during the COP24 United Nations Climate Change Conference in Katowice, Poland, Monday, Dec. 3, 2018. (Peter Klaunzer/Keystone via AP)

Asked about the recent protests in France, one of which turned into a riot in Paris on Saturday, Rutte said politicians must work to get all of society to back the measures needed to tackle climate change.

Actor Arnold Schwarzenegger delivers a speech during the opening of COP24 UN Climate Change Conference 2018 in Katowice, Poland, Monday, Dec. 3, 2018.(AP Photo/Czarek Sokolowski)

"That means talking, talking, talking," he said. "With all societal organizations, politicians, all citizens being involved if they want to."

Leaders and negotiators from almost 200 nations from around the globe talk during the official opening of the key U.N. climate conference COP 24 that is to agree on ways of fighting global warming in Katowice, Poland, Monday, Dec. 3, 2018.(AP Photo/Czarek Sokolowski)

More talk is doubtlessly necessary, including at the international level. Poland's President Duda told reporters that his country, which relies on coal for 80 percent of its energy, would work to reduce its reliance on coal but never entirely give up its "strategic fossil fuel."

Natural historian Sir David Attenborough, second right, listens to speeches during the opening of COP24 UN Climate Change Conference 2018 in Katowice, Poland, Monday, Dec. 3, 2018. (AP Photo/Czarek Sokolowski)

Among those addressing conference participants this week is a 15-year-old Swedish activist, Greta Thunberg, who has inspired students around the world to campaign against global warming.

Trucks are lined up as hey roll down a highway in Frankfurt, Germany, Monday, Dec. 3, 2018. The COP24 UN Climate Change Conference is taking place in Katowice, Poland. Negotiators from around the world are meeting for talks on curbing climate change. (AP Photo/Michael Probst)

Thunberg criticized leaders, such as Trump and German Chancellor Angela Merkel, who failed to come to the climate talks.

In this image taken with a slow shutter speed, vehicles move on a road in Belgrade, Serbia, Monday, Dec. 3, 2018. The COP24 UN Climate Change Conference is taking place in Katowice, Poland. Negotiators from around the world are meeting for talks on curbing climate change. (AP Photo/Darko Vojinovic)

"I think that in the future we will look back and we will either laugh at them or we will hate them," she told The Associated Press. "It's very sad, but if they don't do anything right now that is the truth."

A visitor to the U.N. climate conference takes a selfie at an exhibition about forests and global warming, in Katowice, Poland, Monday, Dec. 3, 2018. The COP24 UN Climate Change Conference is taking place in Katowice, Poland. Negotiators from around the world are meeting for talks on curbing climate change. (AP Photo/Czarek Sokolowski)

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Actor Arnold Schwarzenegger delivers a speech during the opening of COP24 UN Climate Change Conference 2018 in Katowice, Poland, Monday, Dec. 3, 2018. (AP Photo/Czarek Sokolowski)

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