Displays of coal jewellery and coal soap, coal in a glass walkway beneath your feet, coal in the air that you breathe … the Polish hosts of this week’s UN climate talks have been anything but subtle in reminding delegates that we still live in a fossil-fuelled world despite the urgent necessity to move to a cleaner path.

The conference centre is near the mineshaft of the colliery museum in Katowice, the heartland of Silesia’s vast coal industry. The sponsors include JSW, the EU’s largest coking coal producer, and PGE, which runs the world’s second-largest fossil-fuel power plant.

If that were not enough, the summit host, President Andrzej Duda, opened the summit with a boast that his country was sitting on 200 years’ worth of coal supplies and “it will be hard not to use them”. To underscore that intention, PGG, the state-owned thermal coal producer, announced plans during the summit for a new $400m (£320m) shaft at Imielin, 12 miles from Katowice.

Yet for all of this, the single clearest fact that has emerged from this conference is that the world must break from this dirtiest of carbon fuels if we are to have any chance of avoiding dangerous levels of climate disruption.

“We are seeing a coal renaissance. This is disastrous,” said Ottmar Edenhofer, the deputy director at the Potsdam Institute for Climate Impact Research. “We are really at risk. It is not enough to pray. We have to do something.”

It is not just Poland. Coal is on the rise in Japan, Indonesia, India, Vietnam and Russia. In China, the world’s biggest producer, output has increased after several years of declines.

Planned new coal investments in the world would add 330 gigatonnes of CO2 to the atmosphere, Edenhofer said. Added to existing infrastructure, this would use up all of the world’s remaining carbon budget under the Paris agreement. “If we continue with these investments we close the door to 2C,” he said, referring to the world’s least ambitious climate target.

A protester outside the climate conference in Katowice. Photograph: Meghan M Shea/Guardian Community

But there are signs of change. Campaigners are accelerating efforts to halt expansion plans – which lock in consumption for decades – and gradually replace existing collieries with alternative green energies, such as wind and solar.

This is even happening in the host country. This week, 17 Polish cities joined a zero-carbon coalition. A proposal to phase out coal by 2030 has the support of 69% of Poles, according to a survey last month by Greenpeace.

There is also increasing awareness about the true costs of coal, which have long been off the books. Thirty-six of the 50 most polluted cities in the EU are in Poland, mostly in the Silesian region, where visitors can smell the sulphur in the air as they arrive at the airport. Numerous studies have shown the dire health impacts, including an estimated 47,500 premature deaths. This has promoted a growing anti-smog movement.

Climate impacts are also becoming more apparent. Poland suffered heatwaves and droughts this year that reduced harvests and impeded the country’s ability to feed itself.

With the cost of coal likely to rise, Poland is investing heavily in renewables. Wind power, in particular, has risen sharply in the past two decades. The old jobs are now less attractive.

“In the socialist era, the coalminer was a working-class hero, but young people don’t want to work in the mines. The pay is not so good compared with jobs in other EU countries,” said Irma Allen, an anthropologist writing a PhD on coal communities at the KTH Royal Institute of Technology in Stockholm. “Life with coal is now radically different than it was 20 to 30 years ago The costs now outweigh the benefits.”

Easing the pain of transition is a vital political task, say campaigners. Many pits were closed in the 1990s, destroying communities and leaving some laid-off miners’ families so poor they have to scavenge for coal to heat their homes. Pessimism is rife. Miners are not intrinsically anti-environment, says Allen, but their futures are insecure.

“If people were offered an alternative vision of what the region could be, they might be more hopeful,” she said. “But they saw what happened with Thatcher in Britain in the 1980s and fear the same will happen here.”

The Pniówek mine in Pawłowice. Coal is often referred to in Poland as its ‘black gold’ and the industry is a great source of national pride and identity. Photograph: Barbara Lewis/Reuters

Katowice has partly filled the gap by reinventing itself as a cultural centre, conference hub and university city, but the pushback has been fierce from the left and right of the old economy. The Solidarity union, which represents tens of thousands of Polish miners, has joined with the rightwing US lobby group, the Heartland Institute to dispute the science of climate change.

The conservative Duda claims coal is Poland’s gift from God and made keeping pits open a question of national sovereignty.

“This plays to the ultra-nationalist discourse in Poland and elsewhere, but it’s hypocritical,” said Ido Liven, of the CEE Bankwatch Network, one of the biggest environmental groups in eastern Europe. “The Polish president talks about coal as a national treasure yet imports are increasing. Close to 60% of imported coal is from Russia.”

Politicians who have tried to introduce changes are struggling, says Mateusz Klinowski, the former mayor of Wadowice, the birthplace of Pope John Paul II. He lost office in an election this year after trying to cut pollution and wean the city off coal.

“I thought it was enough to build support from the bottom up; to show the facts on health, to talk about pollution, about the morality of change, but it didn’t work. It’s because people are told on TV that coal is a treasure,” said Klinowski.

“But even if I tell them the planet is dying and I will give them 50% of the the cost of a new heating system, they think it’s just green bullshit and not necessary. We need to change the state government and do it at the top level.”

Miners attend a mass in Wadowice to celebrate Saint Barbara, the patron saint of coalminers, whose feast day is on 4 December. A photograph of Pope John Paul II, who was born in the city, hangs in the church. Photograph: Sean Gallup/Getty Images

The economics are moving in a different direction from the politics. The World Bank and other large international finance institutions are withdrawing from coal investments. Insurance companies are also pulling out.

Poland’s neighbours – Hungary, Slovakia and the Czech Republic – have taken strides to cut coal subsidies and bring forward a phase-out date. Elsewhere in the world, there are strong signs the coal renaissance is winding down.

The UK has rapidly switched from coal to renewables with the help of a carbon tax on power supplies. Despite Donald Trump’s rhetoric, coal is plunging in the US. Germany, the biggest coal user in Europe, will conduct a review of its dependency next year that is expected to prompt a radical shift in policy. India is also building so much solar that some believe it may never need to commission another coal plant.

These moves prove the renaissance of coal can be stifled, say academics, businessmen and campaigners, but it needs to be done more quickly – and the main obstacle is at the top.

Adair Turner, of the Just Transition Partnership, said it was possible to build a zero-carbon economy by 2060 at a cost of just half a percent of GDP. “With the technology and the economy I am more confident than I was three years ago, but I’m now less confident about the politics,” he said. “If we don’t get there, it will be because of special interests.”