Direct air capture with carbon storage (DACCS) could help remove nearly five gigatonnes of carbon dioxide (CO₂) from the atmosphere by midcentury. However, this requires the emerging technology, which uses chemicals to capture the heat-trapping gas directly from the air, to develop at a rate similar to other technologies that grew quickly in the past, according to a new study published in PNAS and conducted by an international team of researchers – including at the Complexity Science Hub and WU Vienna.

The research team, led by the University of Wisconsin-Madison, finds that DACCS could be an important tool to combat climate change. "Our results show that DACCS could reduce annual emissions by nearly five gigatons by 2050 if this technology follows the path of fast-growing technologies like photovoltaics," explains Kavita Surana, who is a Professor at WU Vienna, Associate Faculty at the Complexity Science Hub, and Senior Fellow at the University of Maryland. But it might only remove 0.2 gigatonnes per year if it scales at a similar rate to slow-growth technologies such as natural gas pipelines, according to Surana, who holds the BMK Endowed Professorship for Data-Driven Knowledge Generation: Climate Action.

Achieving climate targets

For comparison, global CO₂ emissions exceeded 40 gigatonnes last year. Scientists have found that we need to reach net zero CO₂ emissions by around mid-century to limit global temperature change to 1.5°C, as set out in the Paris Agreement.

“Countries around the world and many other actors – from local governments to corporations to universities – are setting net zero targets,” says Morgan Edwards from the University of Wisconsin-Madison. “We know we will need to rapidly reduce CO₂ emissions at the source, but technologies like DACCS that can remove CO2 directly from the atmosphere could also play an important role.”

Past data for the future

The researchers’ novel approach incorporates indicators of early DACCS adoption with data on technology analogs from the past to design DACCS growth scenarios in models widely used to inform climate policy.

To track innovation growth in hundreds of technologies going back more than a century, the researchers used the Historical Adoption of TeCHnology (HATCH) database. Based on technologies with strategic similarities to DACCS, they explored possible DACCS growth pathways out to 2100. These pathways were then modeled in GCAM, an integrated assessment model to assess how DACCS adoption affects how society can reach a 1.5°C future.

“The wide range of DACCS scenarios highlights the uncertainties inherent in forecasting technology adoption,” says Zachary Thomas from the University of Wisconsin-Madison. “But using historical analogs to tell different stories about the future can help identify the policy environments that could accelerate DACCS development, such as those that have been instrumental for wind and solar energy.”

Investors and corporations

This research is part of a broader portfolio of work on climate and energy technologies, or climate-tech, funded by the Alfred P. Sloan Foundation, which focuses on combining data on start-ups and investments with systems models to better understand the role of innovation in shaping climate outcomes. The authors previously identified corporations as key investors in climate-tech start-ups whose decisions could shape technology trajectories, with DACCS being an important investment area.

“Investors and corporations have a growing interest in DACCS as they set up offtake agreements to purchase captured carbon from start-ups. Using data on start-up announcements, plans, and current capacity for different types of DACCS gives us improved information on early adoption patterns which can in turn better inform how DACCS adoption might scale,” notes Surana.

Important tool

DACCS is one of several carbon dioxide removal (CDR) technologies that capture CO₂ from the atmosphere and store it underground, on land, in the sea, or in durable products. Since the landmark 2015 Paris Agreement established a goal to limit global temperature increases to 1.5°C by approximately the end of the century, researchers have agreed that reaching net-zero emissions by around 2050 will be necessary to meet the target. This will almost certainly require technologies to remove CO₂ from the atmosphere alongside significant emissions reductions.

"Of course, DACCS is just one of many ways to achieve the goal of net-zero emissions, but this study highlights that it is an important tool and how it develops should not be forgotten in the climate policy discussion," says Surana.

Details of the study and further information

Modeling direct air carbon capture and storage in a 1.5°C climate future using historical analogues" M. R. Edwards, Z. H. Thomas, G. Nemet, S. Rathod, J. Greene, K. Surana, K. M. Kennedy, J. Fuhrman and H. C. McJeon.
Link to the study

Note: This text is based on the original published on the website of the University of Wisconsin-Madison