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By Liz Warren-Pederson

Combining policies aimed at removing carbon dioxide from the atmosphere with those aimed at reducing emissions could decrease CO2 concentrations faster than natural processes alone, according to a new paper co-authored by assistant professor of economics Derek Lemoine and published in Climatic Change.

“There are a lot of levers that we can pull to manage atmospheric carbon dioxide concentration in the long term,” explained Lemoine. “What this paper does is consider the interplay between some of those levers.”

Assistant Professor of Economics Derek Lemoine explores economic policies to decrease CO2 emissions.

Assistant Professor of Economics Derek Lemoine explores economic policies to decrease CO2 emissions.

Lemoine and his co-authors modeled a mix of options for achieving long-term climate goals. These options include emission reductions, research and development (R&D) into low-emitting technologies, and negative emission policies that can remove previously emitted carbon from the atmosphere. “We’re looking for the portfolio of policies that minimizes the cost of reaching each long-term climate target,” he said.

“We found a few things that seem intuitive in retrospect,” he continued. “One is that the ability to fund R&D and develop new technologies can greatly lower the cost of attaining the overall target. But that is not a substitute for reducing emissions if we have ambitious targets.  These targets don’t leave us time to delay while we wait for new technologies.”

Lemoine said that the reductions should be part of an overall strategy. But one of the novel aspects of his paper is that it considers emerging technologies that remove CO2 from the atmosphere. These could chemically capture CO2 from the air or could involve capturing emissions from burning biomass for electricity.  “Economic analyses rarely recognize the possibility of negative emission technologies,” he said.

Planning to deploy negative emission technologies shifts optimal R&D funding from “carbon-free” technologies like solar panels into “emission intensity” technologies like capturing coal plants’ emissions. “This is because we could use negative emission technologies to eventually compensate for any remaining carbon emissions and to partially undo previous emissions,” Lemoine said. Making negative emission strategies available enables an 80 percent reduction in the cost of keeping year 2100 CO2 concentrations near their current level.

“But that doesn’t include the possibility of abrupt change in climate,” he said. He and his colleagues find that negative emission strategies are less important if the possibility of tipping points rules out using late-century net negative emissions to temporarily overshoot the CO2 target earlier in the century.  In that case, over-emitting today brings a climate cost that cannot be undone in the future.

Another paper Lemoine has in progress examines how economic policy should adjust for possible tipping points in the climate. Both papers build on his interdisciplinary background in energy and resources. In addition to his appointment at the Eller College, Lemoine is affiliated with the UA Institute of the Environment.

“Solving issues within the complex systems of climate and the environment means that you also have to deal with human systems, which is where economics comes in,” he said.

Learn more about the dynamic range of faculty and research in the Department of Economics.