And the kids laughed in their faces.

That was the bizarre and symbolic scene that unfolded Monday at the UN COP24 climate talks at a spaceship-shaped conference center in Polish coal country.

The nations of the world are meeting here to hash out a "rulebook" to help ensure the viability of humanity -- preventing runaway global warming from causing even greater calamity in the form of superstorms, searing droughts and deadly heat waves.

That work, which follows up on the 2015 Paris Agreement, is seen as more critical now than ever. A damning report from the United Nations this fall said there's only about a decade left to avoid the worst of climate change. The message: cut fossil fuel pollution to "net zero" in just a few decades.

Yet the United States held a discussion on Monday that was meant, among other things, to "showcase ways to use fossil fuels as cleanly and efficiently as possible."

Vic Barrett says US energy policy is "a joke."

Vic Barrett, a 19-year-old college student in Wisconsin, was among those who decided that was too much to take. Barrett and dozens of other protestors erupted in mock laughter as Preston Wells Griffith, an official at the US Department of Energy, spoke about how fossil fuels "will continue to play a role" in the global energy picture. They temporarily stopped the US-led discussion, shouting, "shame on you!" and "keep it in the ground!" -- a reference to fossil fuels that they say should be left unearthed.

"It's so ridiculous. It's a joke," Barrett said of US energy policy. "We're done listening to false solutions [like the promotion of coal] and things we know don't work."

A US State Department spokesperson said the event was intended to show "the remarkable progress we have made through innovation for cleaner technologies."

"These job-creating innovations have contributed to reducing U.S. emissions while also growing our economy and providing reliable and affordable access to energy," a State Department statement said.

Griffith stood quietly behind a lectern during Monday's demonstration. "All too often, we can't have an open and honest discussion about the realities," he said after what he termed a "disturbance" had finished.

"All energy sources are important, and they will be utilized unapologetically," he said. "The important piece is to utilize them in the most cleanly and efficient way, and that's something I think all countries are committed to."

Since the Industrial Revolution, the United States has done more to cause climate change than any other nation, according to the World Resources Institute . In 2015, the US and China emerged as global leaders in the fight against climate change, orchestrating a deal aimed at limiting warming to at most 2 degrees Celsius from pre-industrial levels.

But since President Donald Trump took office, the picture has been far different.

Trump has promised to withdraw the United States from the Paris accord and has sought to expand production of coal, using that talking point to Republican voters.

Climate activists and policy experts say Americans have been trying to throw a wrench in the process here in Poland, which is meant to take the lofty goals of Paris and ensure that they actually become reality. Whether that actually works? That remains to be seen.

The US promotion of fossil fuel interests makes COP24 feel more like a "trade show" than a climate negotiation, said Jesse Bragg, spokesman for the nonprofit group Corporate Accountability. "It feels like the US saying the rest of the world, 'We've got coal and coal technology; come buy it from us,' " he said. "They're not here to negotiate a treaty. They're here to sell fossil fuels."

It's not just the US fossil fuels "sideshow," which is an attempt to prop up an industry that is failing regardless of Trump's policies, said Jake Schmidt, managing director for international programs at the nonprofit Natural Resources Defense Council. Over the weekend, the United States, Russia, Saudi Arabia and Kuwait stood in the way of a statement to "welcome" the dire assessment of climate science from the UN Intergovernmental Panel on Climate Change.

Those four countries wanted only to "note" the existence of the report -- which may sound like a small difference but is actually light-years away in diplomatic speak, Schmidt said.

"It's sort of like saying, 'Yeah, we read it in some newspaper, and there was coverage about it, but we don't have any formal comment on it,' " he said. A "welcome" is an endorsement. "To come here and not welcome it? I don't think that's ever happened. ... It shows this group of countries is not willing to put on the table what's necessary to address climate change."

That is more concerning than the US energy event, he said.

"For everyone else, it was very stunning," said Roger Sedin, a government delegate from Sweden.

Welcoming the report would be the "bare minimum," said Naomi Ages, senior climate campaigner with Greenpeace USA. "They should be saying, 'we're terrified by this, and we're being spurred into action.' "

"The United States was willing to note the report and express appreciation to the scientists who developed it, but not to welcome it, as that would denote endorsement of the report," the US State Department spokesperson said. "As we have made clear in the IPCC and other bodies, the United States has not endorsed the findings of the report."

For years, if not decades, there has been solid scientific consensus around the reality that burning fossil fuels and chopping down forests creates dangerous climate change. This pollution already has contributed to 1 degree Celsius of warming. In Paris, world leaders decided to work together to limit warming to at most 2 degrees -- and 1.5 degrees if at all possible. Some small island states in the Pacific say they may not exist if warming exceeds 1.5 degrees Celsius because sea levels are rising as land-based ice melts and the oceans warm.

The talks in Poland are meant to put those goals into action -- setting the "rulebook" for countries to track the emissions and ratchet up their ambitions over time. Current pledges as part of the Paris Agreement would lead to about 3 degrees Celsius of warming.

It's unclear whether the US effort to promote fossil fuel technologies and avoid "welcoming" scientific reports will derail the important but technical discussions in Poland, experts said.

Regardless of whether the United States "welcomes" the UN's scientific report, the world is hearing the message that action is needed, said Elliot Diringer, vice president of the nonprofit Center for Climate and Energy Solutions.

"The report speaks for itself," he said. "It would be good if all governments were prepared to stand behind it, but even if not, the world is hearing it."

The United States is actually moving away from coal even as it promotes it, Schmidt said.

"It's a sideshow," he said. "It's the US arguing to the rest of the world that it should move forward on technologies the US market is moving away from. No one wants to build a new coal plant in the United States. It's too costly compared to wind and solar and gas."

The importance of this moment isn't lost on young people, who stand to lose more as adults continue to mess up the planet, said Greta Thunberg, a 15-year-old activist from Stockholm, Sweden. She was among those who disrupted the US event.

Greta Thunberg says this is a critical moment for the planet.

"This is a very important meeting," she said of COP24. "People I talk to say this is our last chance. And if we don't get this straight at this meeting, then we're screwed."

She's not sure quite what to make of the talks, she said. She feels a range of emotions about what's happening in what she sees as an absolutely critical moment for the planet.

Her own story has been used as a source of inspiration. Thunberg started a school walkout campaign for climate action. At first, she was the only student who participated; now, tens of thousands are involved, she said. But at the US event on Monday, she had to force laughter.

Otherwise, she said, she may have been hit with a wave of sadness.