CCS Can Safely Store 10x Less Carbon Than Fossil Industry Claims: Scientists

The world has far fewer places to securely store carbon dioxide deep underground than previously thought, steeply lowering its potential to help stem global warming, according to a new study that challenges long-held industry claims about the practice.

The study, published Wednesday in the journal Nature, found that global carbon storage capacity was 10 times less than previous estimates after ruling out geological formations where the gas could leak, trigger earthquakes or contaminate groundwater, or had other limitations, The Associated Press reports. That means carbon capture and storage would only have the potential to reduce human-caused warming by 0.7°C—far less than previous claims of around 5-6°C, researchers said.

“Carbon storage is often portrayed as a way out of the climate crisis. Our findings make clear that it is a limited tool” and reaffirm “the extreme importance of reducing emissions as fast and as soon as possible,” said lead author Matthew Gidden, a research professor at the University Maryland’s Center for Global Sustainability. The study was led by the International Institute for Applied Systems Analysis, where Gidden also is a senior researcher in the energy, climate and environment program.

The study is the latest knock on a technology, for years promoted by oil and gas industry, that has often been touted as a climate solution. Today, carbon capture is far from being deployed at scale, despite billions of dollars in investments and lavish government subsidies around the world, and the amount of carbon currently captured is just a tiny fraction of the billions of tonnes of carbon dioxide emitted every year.

The 2015 Paris climate agreement called for limiting average global temperature increase to 2°C, but ideally below 1.5°C (2.7F), compared to pre-industrial levels in the early 1800s.

Many scenarios for hitting that target have relied on carbon removal and storage, assuming the potential was “very large” because previous estimates didn’t account for vulnerable areas that might not be suitable, said study co-author Alexandre Koberle, a researcher at the University of Lisbon.

“That was never systematically challenged and tested,” said Koberle, adding that the study was the first to examine which areas should be avoided, leading to what the authors call a “prudent potential” that minimizes risks to people and the environment.

The study doesn’t conclude that carbon capture and storage isn’t important to keep global temperatures in check. But researchers said countries must prioritize how they use the limited storage space available and do so in conjunction with fast and deep emissions reductions.

The technology should be used for sectors that are difficult to decarbonize, such as cement production, aviation, and agriculture, and not to extend the life of polluting power plants or prolong the use of oil and gas, Koberle said.

Industry officials defended carbon capture and storage as having an inherently low risk and say emerging technologies, such as storing carbon dioxide in basalt formations where it becomes mineralized, could dramatically increase total storage volumes.

What’s more, its use is “not optional if we hope to address global warming,” said Jessie Stolark, executive director of the Carbon Capture Coalition, adding that it must be combined with other ways to reduce emissions and balanced with the need for reliable and affordable energy. [It isn’t clear from the AP coverage whether the Coalition understands that the most affordable sources of energy across most of the world, solar+storage and wind+storage, require no carbon capture because their operations emit no climate pollution—Ed.]

Rob Jackson, head of the Global Carbon Project, a group of scientists who monitor greenhouse gas emissions, praised the study for its cautionary perspective. Though he’s optimistic that carbon capture technology itself will work, he believes very little will ever be stored “because I don’t think we’re willing to pay for it.”

“If we aren’t willing to cut emissions today, why do we expect that people in the future will just automatically pay to remove our pollution?” Jackson said. “We’re just continuing to pollute and not addressing the root of the problem.”

The most commonly used carbon capture technology allows facilities to capture and store around 60% of their carbon dioxide emissions during the production process, AP writes. Anything above that rate is much more difficult and expensive, according to the International Energy Agency, although that hasn’t stopped some Canadian projects from claiming much better results.

Gidden, the lead author, said it’s clear that scaling up carbon storage will be important to bring emissions to net-zero and to eventually reduce them, and agreed the use of basalt formations is promising. But the world can’t afford to wait for that to happen before acting decisively to slash fossil fuel emissions.

“If we prolong our dependence on fossil fuels for too long with the expectation that we will offset that by simply storing carbon underground, we’re likely saddling future generations with a nearly impossible task of dealing with not only our mess, but limited ways of cleaning it up,” he said.

Cover photo:  Climate Group/flickr