Robert M. La Follette School of Public Affairs
Tuesday, May 22, 2018

Nemet, colleagues review negative emission technologies for reducing CO2

Nemet, colleagues review negative emission technologies for reducing CO2

In three comprehensive studies, an international consortium of 20 researchers, including the La Follette School’s Greg Nemet and Sophia Rogers, found a major gap in climate change dialogue between science and policy. The journal Environmental Research Letters recently published results of the studies by researchers at La Follette, the Mercator Research Institute on Global Commons and Climate Change (MCC), and others.

In the 2015 Paris Agreement on climate change, the international community committed itself to limiting global warming to “well below two degrees Celsius.” Limiting global warming to 1.5 degrees will make the world increasingly dependent on negative emission technologies (NETs); however, technology development is considerably lagging the deployment assumed in climate mitigation scenarios, the researchers said.

A Systematic Review of Negative Emissions Technologies

Negative emissions - Part 1: Research landscape, ethics and synthesis
Minx J C, Lamb W F, Callaghan M W, Fuss S, Hilaire J, Creutzig F, Amann T, Beringer T, de Oliveira Garcia W, Hartmann J, Khanna T, Lenzi D, Luderer G, Nemet G F, Rogelj J, Smith P, Vicente L V, Wilcox J and del Mar Zamora M, Environ Res. Lett.

Negative emissions - Part 2: Costs, potentials and side effects
Fuss S, Lamb W F, Callaghan M W, Hilaire J, Creutzig F, Amann T, Beringer T, de Oliveira Garcia W, Hartmann J, Khanna T, Luderer G, Nemet G F, Rogelj J, Smith P, Vicente L V, Wilcox J, del Mar Zamora M and Minx J C 2018 Environ. Res. Lett.

Negative emissions - Part 3: Innovation and upscaling
Nemet G F, Callaghan M W, Creutzig F, Fuss S, Hartmann J, Hilaire J, Lamb W F, Minx J C, Rogers S and Smith P 2018 Environ. Res. Lett.

In addition, the necessary deployment of NETs is hardly discussed in policy discussions. Lack of debate is problematic in that some NETs, which extract CO2 from the atmosphere, involve considerable conflicts for land use, water consumption, energy requirements, among others, they said.

Negative emissions will likely feature prominently in the Special Report of the Intergovernmental Panel on Climate Change (IPCC) on the 1.5-degree target, which will be published in fall.

“If negative emission technologies are to be massively scaled up by mid-century in the way many integrated assessment scenarios portray them, then the innovation literature implies that we should be seeing demonstrations, niche applications, and early adoption occurring imminently,” said Nemet, an associate professor. “However, the NETs literature we reviewed does not at all reflect this urgency, nor do existing policies.”

Nemet, who worked with MCC in Berlin, Germany, during the 2015–16 academic year, led the review on NETs innovation and upscaling.

NETs aim to remove carbon dioxide (CO2), the major driver of manmade climate change, from the atmosphere. They include relatively simple options like planting more trees that lock up CO2 as they grow, or crushing rocks that naturally absorb CO2 and spreading them on soils so that they remove CO2 more rapidly.

Overall, the researchers reviewed more than 6,000 documents on seven groups of technologies: bioenergy with carbon capture and storage (BECCS), afforestation and reforestation, direct air carbon capture and storage (DACCS), enhanced weathering, ocean fertilization, biochar, and carbon sequestration in soil. Through a systematic process and big data methods, they identified 1,000 studies that provided relevant information on the potential, costs, and side effects of CO2-removal technologies.

According to the studies, all technologies have relevant potential – except ocean fertilization. However, they differ in terms of costs, side effects, development status, and long-term storage potential.

“Although policymakers like to set ever more ambitious targets in the climate negotiations, the concrete actions so far are lagging far behind. The result is a growing dependence on negative emissions,” says Jan Minx, head of the MCC Working Group on Applied Sustainability Science. “There is an urgent need for the international community not to further increase but reduce its dependence on technologies for carbon removal from the atmosphere. To achieve this, we need to reduce greenhouse gas emissions much more rapidly.”

Through their systematic literature analysis, the researchers found that almost two-thirds of the literature focuses on the early phases of NET research and development.

“The actual use of new technologies and their upscaling takes a lot of time. That makes it all the more important to support these steps through research,” said Sabine Fuss, head of the MCC Working Group for Sustainable Resource Management and Global Change. “In order to clarify the opportunities and risks of negative emissions and to make them possible on an industrial scale, a roadmap for pilot projects must be developed. This will certainly have to cover several different technologies – a focus on just one technology at this scale would be too risky.”

On May 31, The Washington Post published an opinion piece by Nemet and Minx titled Our Lives Depend on Carbon Capture. But the Tech is Far from Ready.