PerspectiveClimate Change

The trouble with negative emissions

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Science  14 Oct 2016:
Vol. 354, Issue 6309, pp. 182-183
DOI: 10.1126/science.aah4567

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  • RE: Troubles without negative emissions
    • Michael Obersteiner, Program Director, International Institute for Applied Systems Analysis
    • Other Contributors:
      • Kenneth Möllersten, International Institute for Applied System Analysis
      • Jerry Yan, Professor, Royal Institute of Technology (KTH) and Mälardalen University (MDH)
      • Matthew Cantele, Research Assistant, International Institute for Applied Systems Analysis
      • Florian Kraxner, Deputy Director, International Institute for Applied Systems Analysis
      • Petr Havlik, Senior Research Scholar, International Institute for Applied Systems Analysis
      • Josep Peñuelas, Professor, Centre for Ecological Research and Forestry Applications
      • Ivan Janssens, Professor, University of Antwerp
      • Philippe Ciais, Associate Director, Laboratoire des Sciences du Climat et l'Environnement
      • Thomas Brooks, Head, Science and Knowledge, International Union for Conservation of Nature
      • Jeffrey Sachs, Professor, Columbia University
      • James Watson, Director, Wildlife Conservation Society

    “The trouble with negative emissions” (1) raises important technological risk and intertemporal equity arguments against overreliance on negative emissions technologies (NETs) to achieve ambitious climate targets. Instead of discounting the value of NETs (1, 2), we argue that NETs are indispensable in an era of planetary risks associated with an increasingly disturbed climate system, and need to be sufficiently prepared in advance. Climate mitigation strategies that deplete the full capacity of NETs in order to undo an emission overshoot in the first half of the 21st century indeed represent a dangerous high-stakes gamble. The use of NETs was originally conceived as a risk management tool to buffer against not only climate system uncertainties (3, 4), but also those associated with global politics (5), risks which have not dissipated (6). Clearly, ambitious climate targets such as that of the Paris Agreement would become unattainable without a sufficiently large negative emission buffer should natural land and ocean carbon sinks weaken or switch to sources of emissions. Likewise, massive amounts of negative emissions will be needed if major countries continue to believe that an emission peak in2030 is still compatible with the Paris Agreement (7).

    Large investments are needed in the natural, technological and human resources necessary to form a NET bulwark against unanticipated carbon cycle emergencies. An acceleration of ecosystem restoration programs recarbonizing...

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    Competing Interests: None declared.