Maybe we don’t have to capture so much carbon, study suggests

New technologies and changes in consumer habits could limit the use of controversial carbon capture to fight climate change, new research shows.

Efforts to capture carbon from polluting sources or to filter CO2 out of the air have picked up steam as a way for companies to meet their climate goals. But those strategies are still unproven at a large scale and could come with other unintended consequences. Some environmental advocates also worry that focusing on cleaning up pollution after the fact could lure companies away from transitioning to renewable energy to prevent emissions in the first place.

To stop climate change and meet the goals of the Paris agreement, planet-heating carbon dioxide emissions need to reach net zero around 2050. There’s no way to do that without turning to cleaner energy. Certain industries, however, are considered difficult to decarbonize, meaning they can’t turn to renewable electricity as easily as other sectors to reduce carbon pollution. That includes agriculture, international transport by ship and plane, and heavy industry like steel and cement manufacturing.

That’s where carbon dioxide removal (CDR) is supposed to come in as a way to draw down that leftover pollution from hard-to-decarbonize sectors. A paper published last week, however, pushes industry and policymakers to be more ambitious. There are ways to prevent more of that pollution either by leaning into emerging technological solutions or by encouraging more sustainable consumer habits.

“Are there not measures that can be taken that are tenable, right? That’s the question,” says Wil Burns, co-director of the Institute for Responsible Carbon Removal at American University, who was not involved in the new research.

The authors of a paper published in the journal Nature Climate Change last week scoured previous research to identify ways each of those hard-to-abate sectors could cut down their pollution. Lighter-weight and more efficient aircraft would reduce pollution from international travel, as would efforts to develop cleaner-burning fuel. Increased teleworking and taking high-speed rail instead of short-distance flights would also cut down on carbon pollution. When it comes to making steel, electric arc furnaces can replace traditional blast furnaces. One of the biggest ways people could make an impact, they found, would be to cut down on the amount of meat and dairy they consume.

The researchers analyzed scenarios in which people deploy those strategies to reduce emissions from hard-to-decarbonize industries and compared the outcomes to a baseline scenario for climate action without such measures. That showed them how much they could reduce the use of one of the most contested carbon removal strategies, called bioenergy with carbon capture and storage (BECCS).

The baseline scenario, which is based on a model commonly used to inform climate action, prioritizes cost savings. “In a way, it finds the cheapest options to reduce emissions,” says Oreane Edelenbosch, lead author of the research and an assistant professor at Utrecht University. “BECCS is an option that is attractive from a cost perspective.”

BECCS involves capturing and storing carbon dioxide from wood-burning power plants. The power plant burns fuel from trees that naturally take in and store CO2. Burning those trees releases that CO2, but you can replant trees to try to capture those emissions again. Ideally, that becomes a carbon-neutral process for generating energy. The goal with BECCS, though, is negative emissions, which is achieved by installing devices to capture the power plant’s pollution. That carbon negativity is meant to cancel out the climate impact of hard-to-abate emissions from heavy industry, transport, and agriculture.

BECCS hasn’t been very widely deployed yet, although that could change with interest from companies like Microsoft, which recently agreed to a deal with energy company Stockholm Exergi to purchase 3.33 million metric tons of carbon removal from BECCS.

But BECCS can take a toll in different ways. There are additional emissions from clearing forests and transporting wood to burn as fuel. With that in mind, some studies have found that BECCS isn’t necessarily carbon negative and can actually worsen greenhouse gas pollution in the atmosphere. Burns points out that there are human rights concerns with BECCS, too, since it uses a lot of land and water and can raise food prices for communities already facing food insecurity.

The authors of the new paper find that implementing technological solutions for hard-to-decarbonize sectors could dramatically reduce the annual use of BECCS by 2060. Changing consumer behavior was especially powerful, particularly switching to “healthy” diets that cut down on meat and agricultural emissions. Looking at those kinds of lifestyle changes alone, BECCS might only be used to draw down up to 2.2 gigatons of carbon dioxide a year compared to a peak of 10.3 gigatons annually in a baseline scenario.

Of course, it’s easier to envision this on paper than to implement all of these strategies in the real world. “[In this study] we assume that they are implemented and they are adopted in almost like a perfect world. We don’t take into account political views or certain personal preferences,” Edelenbosch says. “It really more shows, in a way, what if?”