The Petra Nova Carbon Capture Project at the NRG Energy W.A. Parish generating station in Thompsons, Tex., in 2017. The project reportedly captures and repurposes more than 90 percent of the plant’s carbon dioxide emissions. (Luke Sharrett/Bloomberg News)

With most of the world’s nations seemingly unable to stop pumping greenhouse gases into the atmosphere, some climate experts here are focusing on coming up with an economic way to remove them.

Fueled by glum reports about the trajectory of global carbon emissions, more and more businesses, policymakers and researchers are coming to the same conclusion: The world must improve and commercialize methods to capture carbon dioxide from the air and store it or find practical uses for it.

The focus on carbon capture comes as representatives here from nearly 200 nations try to hash out how the world can collectively combat climate change by reducing emissions. What has been largely a science experiment now seems to be a vital way to come up with a technological breakthrough that can reduce and maybe one day reverse some of the damage being done.

“As we look out to the middle of the century, one thing is very clear: Going to net zero [emissions] will require carbon capture and storage on a substantial scale,” said Nicholas Stern, a climate economist and chair of the London-based Grantham Research Institute. “And we’re going to need it quite soon.

It’s a long shot.

In the past, carbon capture drew little interest — and for good reason. Most methods of carbon capture used too much energy and cost too much money. With the exception of pumping carbon dioxide into old wells to enhance oil recovery, carbon capture also had no compelling commercial application.

Yet a growing sense of desperation about the state of the climate has people taking a harder look at carbon capture, which was featured in a side meeting Tuesday at the U.N. climate talks.

“It is one of — and I stress, one of — the necessary technologies to address emissions and to slow the rate of change and, ultimately, achieve that objective from the Paris agreement of net zero emissions,” said Brad Page, chief executive of the Global CCS Institute, which describes itself as the leading authority on carbon capture and storage. “We’re going to need every single technology we can get our hands on.”

So far, 18 carbon capture facilities are in operation, five are under construction and 20 are in various stages of development, according to the CCS Institute. But most of them are relatively small, compared with the scale of the plants needed to make a dent in mitigating climate change.

Page said the industry now has the capacity to permanently remove about 40 megatons of carbon dioxide from the atmosphere each year. That is not insignificant, but that capacity would need to grow by about 200 times to avert severe warming, experts have estimated.

“It is a big expansion, but of course we have seen quite phenomenal expansions elsewhere, very good ones in solar and wind and so on,” Stern said. “But these things happen only if you pursue them, only if you invest now.”

Six countries — Norway, the United States, Britain, China, Canada and Japan — have policies to encourage the building of more plants. The United States last year provided tax incentives for carbon capture. The value of the credits ranges from $10 for carbon dioxide used in enhanced oil recovery to as much as $50 a ton for storage that does not produce any revenue.

A wide variety of carbon capture technologies exist. All share the goal of sucking carbon dioxide, the most common greenhouse gas, out of the flue streams of coal- or gas-fired power plants or even out of the air. After that, the carbon dioxide can be stored in old oil and gas or saline reservoirs. In limited places, it can be put to commercial use buried in concrete or converted into lime that goes into making cement.

“Carbon removal is now a thing,” said Julio Friedmann, a senior research scholar at Columbia University’s Center on Global Energy Policy, speaking from the climate conference in Poland. “It was not on anybody’s agenda. Now it’s front and center.”

But costs are still very high, hovering around $100 a ton of carbon dioxide. The few places where companies are experimenting with carbon capture are places with subsidies.

A variety of pilot projects failed in the past. One was a joint effort by one of the largest U.S. utilities, American Electric Power, and the Energy Department to capture 15 percent of emissions from coal-fired power plants. It closed down after two years. Another carbon capture project attached to a new coal-fired power plant in Mississippi ran into so many technical problems and billions of dollars in cost overruns that after six years its owners abandoned the carbon capture project and converted the plant to burn natural gas for power generation.

Several factors are bringing more policymakers, entrepreneurs, researchers and others to more closely consider carbon capture.

First is the recent U.N. report warning that greenhouse gas emissions must be cut in half by 2030, an unlikely prospect.

Second is another report pointing to the growing gap between policies adopted at the Paris climate conference in 2015 and what is needed to limit the warming of the climate to 2 degrees Celsius above preindustrial levels.

And third is the International Energy Agency’s showing that existing power stations, vehicles and industrial facilities would through 2040 be enough to consume 95 percent of the “carbon budget” — the amount of carbon that can be emitted while sticking to the 2-degree goal.

“A lot of people who thought maybe we don’t have to do [carbon capture and storage] are now realizing that we have to do it,” Friedmann said.

Friedmann, who was principal deputy assistant secretary for fossil energy at the Energy Department under President Barack Obama, said carbon capture costs have fallen 60 percent in the past 10 years. “And we are poised to see that cost get cut in half or more again in the next five or 10 years,” he said.

At Tuesday’s event in Poland on carbon capture and storage, experts fielded questions on how to finance projects, what role governments should play and how quickly the industry might be able to grow. At one point, an attendee asked the panel whether carbon capture is a “safe” technology and what risks it could pose.

“The carbon dioxide in the atmosphere,” Stern replied, “is far more dangerous than the carbon dioxide underground could ever be.”