MADISON, Wis. – A host of emerging methods that remove carbon dioxide from the atmosphere can be critical tools to limit global temperature increases, so long as policymakers don’t overestimate the methods’ role in their climate strategies. This is according to research published yesterday in Nature Communications led by PhD student Matilyn Bindl from UW-Madison’s Nelson Institute for Environmental Studies and Assistant Professor Morgan Edwards of the La Follette School of Public Affairs.
According to the study, governments and industries could maximize the likelihood of achieving climate goals if they initially keep expectations around future scalability of carbon dioxide removal (CDR) low. To be most effective, these actors should invest early in emerging CDR methods while pursuing ambitious emissions reductions at the source.
CDR refers to a collection of approaches for removing CO2 from the atmosphere and durably storing it for decades to millenia. Examples of conventional methods include planting trees and using soil to capture carbon. Newer methods include technologies such as direct air carbon capture and storage (DACCS), which uses chemicals to capture the heat-trapping gas directly from the air, and bioenergy with carbon capture and storage (BECCS), which captures and stores CO2 from processes where biomass is converted into energy.
“Existing and emerging CDR methods could play a key role in meeting the ambitious goals of the Paris Agreement,” says Bindl. “These methods would reduce the overall amount of CO2 in the atmosphere as well as compensate for hard-to-eliminate emissions sources, like cement production and aviation.”
Bindl, Edwards, and their co-author Ryna Yiyun Cui from the University of Maryland’s Center for Global Sustainability used a research design that combines decision analysis and a state-of-the-art integrated assessment model. They used this to simulate a two-stage decision problem, where policymakers act and then later learn about the potential for CDR methods to scale. This produced a set of six possible futures, each representing a different approach to climate policy and the role of CDR. Decision analysis is a systematic approach to evaluating important choices that organizations and institutions make.
Using this analysis, they found that we could limit global temperature increase to 1.5 degrees Celsius in 2100 if policymakers initially plan for low CDR levels, later learn that extensive CDR is possible, and then adopt CDR alongside conventional mitigation methods. This temperature change is in line with the Paris goal to limit global warming to well below 2 degrees Celsius by 2100. This scenario would result in an 81% reduction in fossil fuels for electricity by 2050 and greater equity across the globe, benefiting regions across Africa, South America, and parts of South Asia who have contributed the least to CO2 emissions.
Alternatively, if policymakers plan for high future levels of CDR, learn that CDR is not possible, and do not course correct, it could result in a global temperature increase of 2.4 degrees Celsius by 2100. It would also lead to a delayed phaseout of fossil fuels for electricity generation and the lowest levels of any of the scenarios for early retirement of fossil fuel infrastructure and low-carbon technology investment.
“The consequences of being wrong about CDR scale-up could be substantial, making achievement of the Paris Agreement goals very costly or even impossible,” says Edwards. “By exploring a variety of possible CDR futures through modeling, we see the clear benefits of supporting ambitious climate action in the near term alongside equitable scaling of CDR.”
This research is part of a broader portfolio of work at the Climate Action Lab at UW—Madison, led by Edwards, where Bindl is a member. Their work on climate and energy technologies was supported by a grant from the Alfred P. Sloan Foundation, which focuses on combining data on climate-tech start-ups with systems models to better understand the role of innovation in shaping climate outcomes.
Edwards is also part of the Executive Team of the State of Carbon Dioxide Removal, whose reports serve as the most comprehensive, ongoing analysis and assessment of CDR development across the globe, with the third edition slated for 2026.
