Carbon dioxide removal is expected to play an important role in many pathways to U.S. net-zero emissions, particularly for offsetting emissions from sectors that are difficult to decarbonize. But new research from the University of Virginia and collaborators finds that relying more heavily on removal as opposed to reducing emissions can carry an overlooked public health cost.
Published in the journal Environmental Science & Technology, the study examines the impacts and costs of deploying carbon dioxide removal technologies at the scales needed to meet ambitious climate goals. While removal can help offset emissions from sectors that are difficult to decarbonize, researchers discovered that relying heavily on these technologies demands important trade-offs that policymakers should consider.
The interdisciplinary team was led by Ph.D. candidate Parisa Javadi and included scientists from the University of Maryland and Duke University. The research was developed through the Virginia Climate Restoration Initiative. The study models six carbon removal approaches across pathways to U.S. carbon neutrality by 2050.
Both a high-removal and a low-removal pathway avoid roughly the same amount of climate damage, an estimated $2.5 trillion to $5.8 trillion by 2050. But the pathways have very different costs and health outcomes.
The low-removal pathway, which prioritizes eliminating emissions rather than compensating for them through carbon dioxide removal, delivers 26% greater public health benefits and prevents roughly 12,600 additional premature deaths by mid-century. The difference is largely tied to air pollution: avoiding fossil-fuel emissions also avoids the air pollution produced when those fuels are burned. Relying more heavily on carbon dioxide removal can reduce the amount of carbon dioxide in the atmosphere without eliminating those sources of pollution.
“A ton of carbon dioxide removed from the atmosphere can have the same climate benefit as a ton of emissions avoided, but the two choices can have very different consequences for people,” said Javadi. “When we rely more heavily on carbon dioxide removal, we can leave more fossil-fuel pollution in the places where it is being produced. That means a climate strategy that looks cheaper on paper can come with a very real public health cost for communities living near those sources of pollution.”
Rather than viewing carbon dioxide removal as a replacement for reducing emissions, the study emphasizes that it should complement aggressive efforts to cut fossil-fuel use. Diversified portfolios of carbon dioxide removal technologies can help reduce unintended consequences compared with relying too heavily on a single approach.
“Carbon dioxide removal is going to be important for managing the impacts of climate change,” said Andres Clarens, associate director of the UVA Environmental Institute and a researcher on the team. “Because the industry is still in its early stages, this is an important moment to identify these trade-offs and make sure the systems we build deliver the greatest possible benefits for both the climate and society.”
“Climate solutions should improve people’s lives as well as stabilize the climate,” Javadi said. “By considering air quality, public health, economic, climate and environmental outcomes together, we can make better decisions about which carbon dioxide removal strategies to pursue and where they can deliver the greatest overall benefit.”
The research was supported by the Alfred P. Sloan Foundation, the UVA Environmental Institute, and the National Science Foundation.