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When Iceland’s Eyjafjallajokull volcano erupted in 2010, . Thousands of tons of carbon dioxide were released and mineral ash shot 30,000 feet into the atmosphere, halting air travel across Europe. But closer to the source, scientists observed : a nearby river, the Hvanná, began to run milky white and large chalky, chunks formed along its banks. The strange substance, it turns out, was essentially solid CO2—a carbonate, technically—released from the explosion and trapped in solid form rather than released as a gas.

This process—turning earth-warming carbon dioxide into a solid instead of spewing it into the atmosphere—is at the heart of what’s called carbon capture and sequestration (CCS) technology. CCS involves  underground, where the gas won't affect the climate. It typically takes thousands of years for CO2 to chemically bind with the surrounding rock underground and environmentalists fret that the gaseous emissions could eventually escape. But a new paper published today in the journal Science details a discovery that could accelerate that process and, ultimately, help us get a handle on the most acute cause of climate change. 

“We need to deal with rising carbon emissions,” says lead author . “This is the ultimate permanent storage—turn them back to stone.”

In the paper, researchers from Columbia University’s Lamont-Doherty Earth Observatory demonstrated that they could take emissions from a power plant in Iceland, then turn the CO2 into a solid within a matter of months. The discovery shows the potential for safely collecting and storing carbon without the fear of CO2 later leaking out and wrecking the climate.

The , working with professors from the University of Iceland and the University of Copenhagen, carried out the test at southwest Iceland’s Hellisheidi power plant, one of the largest geothermal plants in the world. At the facility, CO2 was captured before it escaped into the atmosphere, then the gas was mixed with water and injected deep into the volcanic soil. Within two years, 95 percent of the CO2 was solid.

“This means that we can pump down large amounts of CO2 and store it in a very safe way over a very short period of time,” the paper’s coauthor, Columbia hydrologist Martin Stute, says. “In the future, we could think of using this for power plants in places where there’s a lot of basalt,” the porous, volcanic rock that makes up nearly all of the seafloor and about 10 percent of dry land.  

Carbon capture and sequestration is not new technology. It’s been studied for climate change mitigation since the 1980s and 22 CCS projects are already operating or under construction worldwide, . In North America, carbon is captured from coal-fired plants then liquidized and pumped into local geological formations. But most power plants here are not located on volcanic soil like they are in Iceland, and the carbon in the ground can take centuries to solidify, leading to consistent concern from environmentalists that the CO2 will seep back out. Plus, high profile projects have been . The , a proposed “clean coal” power plant outside Odessa, Texas, that’s already received over $100 million in Department of Energy Funding, . And in Canada, the world’s first carbon capture project, a $1 billion electrical plant, has and faced shutdowns. 

Still, carbon capture is an enticing prospect. It allows us to continue burning fossil fuels while potentially mitigating their most damaging aspects. The Intergovernmental Panel on Climate Change to help offset emissions and , including the National Resource Defense Council, support it. And yet parties on all sides of the debate remain skeptical. “CCS is an orphan among climate options,” says John Thompson of the Clean Air Task Force, a pro-CCS environmental group. “It’s not loved by environmental groups—many of them, they see it as fossil fuel enabling—it’s not loved by the industry because its seen as a regulatory burden.”

Says Kyle Ash, Greenpeace’s senior legislative representative: “While [the Iceland project] and some other geoengineering technological collaborations on carbon pollution are academically interesting, they also present a moral hazard for politicians looking for any reason to postpone fossil fuel phase out.”

Furthermore, the new study may put to rest one of environmentalist’s bigger concerns about CCS—that the CO2 could leak from its underground storage—but it does nothing to eliminate the most serious barrier: cost. Capturing carbon costs money, about $100 per ton, plus another $10 to $30 to to inject it underground, according to Thompson. To put that into perspective, America’s coal-fired power plants . Without stronger climate policies that punish CO2 emissions, there’s little incentive for plants to implement the technology.

“Without a policy driver that requires deep CO2 emission reductions, any technology to capture and store CO2 will cost more than business as usual—i.e., continuing to emit CO2 into the atmosphere,” Edward Rubin, a professor Environmental Engineering and Science at Carnegie Mellon who has studied the economics of CCS, wrote in an email. “If the Iceland process works as described, and also works in many other locations (which is not at all clear), it will unavoidably add to the cost of CCS.”

The best way forward for this promising technology is policy, says Thompson, lamenting inaction from politicians and bureaucrats. “It’s hard to imagine solving climate change without CCS.”