First Workshop of the Carbon Dioxide Removal Model Intercomparison Project; Potsdam, Germany, 20–22 September 201

Keller, David P.

Lenton, Andrew

Pfister, Patrik

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How Will Earth Respond to Plans for Carbon DioxideRemoval?First Workshop of the Carbon Dioxide Removal ModelIntercomparison Project; Potsdam, Germany, 20–22 September 2016Smokestacks puffing gas. At a September 2016 workshop in Potsdam, Germany, participantsdiscussed current and future experiments for the Carbon Dioxide Removal ModelIntercomparison Project and Earth system response to negative emissions. Credit: CurranKelleherBy Andrew Lenton, David Keller, and Patrik Pfister! 22 March 2017The recent Paris Agreement (21st Conference of the Parties (COP21 (https://eos.org/articles/landmark-paris-climate-accord-comes-into-force))) recognized that carbon dioxide removal (CDR), ornegative emissions, may be required to limit global warming to the agreed target of less than2°C. In this context, there is an urgent need to assess how CDR could help mitigate climateHow Will Earth Respond to Plans for Carbon Dioxide Removal? - Eos https://eos.org/meeting-reports/how-will-earth-respond-to-plans-fo...1 of 4 24/03/17 13:49change or even reverse it. In response to COP21 and to better understand the potential risksand benefits of different options, the Carbon Dioxide Removal Model IntercomparisonProject (CDR-MIP (http://www.kiel-earth-institute.de/CDR_Model_Intercomparison_Project.html)) wascreated to coordinate and advance our understanding of CDR in the Earth system. Negative emissions may be required to limit global warming to the agreed target of less than2°C.The inaugural CDR-MIP workshop (http://www.kiel-earth-institute.de/meetings.html) in Potsdam,Germany, brought together experts in Earth systems and integrated assessment modeling toinvestigate CDR-MIP simulations and discuss new experiments and their design. Participantspresented results on the first CDR-MIP experiment (C1) on climate reversibility and workedto finalize the designs of additional phase 1 CDR-MIP experiments (C2, C3, and C4). Theworkshop also sought to link the experiments to upcoming policy-relevant assessments likethe Intergovernmental Panel on Climate Change special report (https://www.ipcc.ch/report/sr15/)on global warming of 1.5°C.Results from the C1 experiments found that peak carbon dioxide (CO2) in the atmosphereprecedes peaks in all climate variables and may alter the spatial patterns of climatevariability. After peak CO2, some climate variables (e.g., temperature) return quickly to theirpreindustrial value. Other variables, like ocean overturning circulation (https://eos.org/research-spotlights/major-ocean-circulation-pattern-at-risk-from-greenland-ice-melt), which plays a critical role incontrolling weather and climate, peak several decades later and can take hundreds tothousands of years to return to their preindustrial value. These results have profoundimplications for the emission trajectories needed to reach the goals of the COP21 agreementand maintain key ecosystem services such as food production. The results may also informsocial responses and strategies for adapting to a changing climate.How Will Earth Respond to Plans for Carbon Dioxide Removal? - Eos https://eos.org/meeting-reports/how-will-earth-respond-to-plans-fo...2 of 4 24/03/17 13:49Experimental results from the first experiment of theCarbon Dioxide Removal Model IntercomparisonProject (CDR-MIP C1), showing the response of theEarth system to increasing and decreasing atmosphericCO2 levels from preindustrial to 4 times thepreindustrial concentration of CO2. Credit:BERN3D-LPX modelFuture C2 experiments will quantify the efficiency and response of the Earth system to directCO2 air capture, with a particular focus on carbon-climate feedbacks. One remainingexperiment will focus on afforestation and reforestation (http://www.ipcc.ch/ipccreports/sres/land_use/index.php?idp=47)—extending and restoring forest cover (C3). Another involvesocean alkalinity injection, simulating enhancing natural weathering by adding alkalinity-altering materials such as calcium oxide and olivine to the ocean to enhance its capacity todraw CO2 out of the atmosphere (C4).Given the increasing interest in CDR methods not included in the phase 1 experiments,participants also discussed additional experiments. Among the possibilities, they examinedthe feasibility of experiments focusing on bioenergy carbon capture and storage, whichunderpin many proposed low-carbon pathways. It was also widely acknowledged that there isan increasing demand for future experimental designs that combine different CDRtechniques. One option involved collaborations with the Geoengineering ModelIntercomparison Project (https://eos.org/meeting-reports/understanding-how-climate-engineering-can-offset-climate-change) to combine CDR with solar radiation management methods. Likewise,non-CO2 greenhouse gas removal was also seen as an important topic to investigate.They examined the feasibility of experiments focusing on bioenergy carbon capture andHow Will Earth Respond to Plans for Carbon Dioxide Removal? - Eos https://eos.org/meeting-reports/how-will-earth-respond-to-plans-fo...3 of 4 24/03/17 13:49storage, which underpin many proposed low-carbon pathways.The data generated by the CDR-MIP will be publicly available. We encourage othercommunities, like those working on adaptation and biological impacts, to use the data toexplore the potential future response of the Earth system to CDR. We welcome othermodeling groups interested in submitting simulations to join CDR-MIP.We acknowledge support for this workshop from the Institute for Advanced SustainabilityStudies and a German Research Foundation (DFG) grant (KE 2149/1-1) and thank VivianScott for help in preparing the manuscript. CDR-MIP is jointly led by David Keller, AndrewLenton, Naomi Vaughan, and Vivian Scott.—Andrew Lenton (email: andrew.lenton@csiro.au (mailto:andrew.lenton@csiro.au)), Oceans andAtmosphere, Commonwealth Scientific and Industrial Research Organisation, Hobart,Australia; and Antarctic Climate and Ecosystems Co-operative Research Centre, Hobart,Australia; David Keller, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany; andPatrik Pfister, Climate and Environmental Physics, Physics Institute, University of Bern,Switzerland; and Oeschger Center for Climate Change Research, University of Bern,SwitzerlandCitation: Lenton, A., D. Keller, and P. Pfister (2017), How will Earth respond to plans for carbon dioxide removal?,Eos, 98, https://doi.org/10.1029/2017EO068385. Published on 22 March 2017.Subject to Crown copyright.How Will Earth Respond to Plans for Carbon Dioxide Removal? - Eos https://eos.org/meeting-reports/how-will-earth-respond-to-plans-fo...4 of 4 24/03/17 13:49

How Will Earth Respond to Plans for Carbon Dioxide Removal?

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How Will Earth Respond to Plans for Carbon Dioxide Removal?

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