As leaders attending the UN's annual climate summit heard fresh warnings about the dire consequences of leaving global warming unchecked, a new issue emerged 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 1.5C 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 finalise.
UN Secretary-General Antonio Guterres issued a dramatic appeal to leaders to take the threat of global warming seriously, calling it "the most important issue we face".
He told delegates: "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 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.
British broadcaster Sir David Attenborough echoed his warnings, saying the "collapse of our civilisations and the extinction of much of the natural world is on the horizons" if no urgent action is taking against global warming. He blamed humans for the "disaster of global scale, our greatest threat in thousands of years".
He said: "The world's people have spoken, their message is clear, time is running out, they want you, the decision-makers, to act now. They're supporting you in making tough decisions but they're also willing to make sacrifices."