Assessing “Dangerous Climate Change”: Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature

• Published in: PLoS ONE
• Main Authors: Hansen, James, Kharecha, Pushker, Sato, Makiko, Masson-Delmotte, Valerie, Ackerman, Frank, Beerling, David J., Hearty, Paul J., Hoegh-Guldberg, Ove, Hsu, Shi-Ling, Parmesan, Camille, Rockstrom, Johan, Rohling, Eelco, Sachs, Jeffrey, Smith, Pete, Steffen, Konrad, Van Susteren, Lise, von Schuckmann, Karina, Zachos, James C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: PLOS One 2013
• Subjects: carbon dioxide; carbon sequestration; climate change; fossil fuels; ice sheet; oceans; paleoclimatology; paleopedology; Austin; Queensland; Sheffield; Laplace; Jeremy; Hoegh; Ice Sheet
• Online Access: http://hdl.handle.net/2152/27927; https://doi.org/10.1371/journal.pone.0081648

James Hansen, Pushker Kharecha, Makiko Sato, Jeffrey Sachs, Earth Institute, Columbia University, New York, New York, United States of America Pushker Kharecha, Goddard Institute for Space Studies, NASA, New York, New York, United States of America Valerie Masson-Delmotte, Institut Pierre Simon Laplace, Laboratoire des Sciences du Climat et de l’Environnement (CEA-CNRS-UVSQ), Gif-sur-Yvette, France Frank Ackerman, Synapse Energy Economics, Cambridge, Massachusetts, United States of America David J. Beerling, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, South Yorkshire, United Kingdom Paul J. Hearty, Department of Environmental Studies, University of North Carolina, Wilmington, North Carolina, United States of America Ove Hoegh-Guldberg, Global Change Institute, University of Queensland, St. Lucia, Queensland, Australia Shi-Ling Hsu, College of Law, Florida State University, Tallahassee, Florida, United States of America Camille Parmesan, Marine Institute, Plymouth University, Plymouth, Devon, United Kingdom Camille Parmesan, Integrative Biology, University of Texas, Austin, Texas, United States of America Johan Rockstrom, Stockholm Resilience Center, Stockholm University, Stockholm, Sweden Eelco J. Rohling, School of Ocean and Earth Science, University of Southampton, Southampton, Hampshire, United Kingdom, Eelco J. Rohling, Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia Pete Smith, University of Aberdeen, Aberdeen, Scotland, United Kingdom Konrad Steffen, Swiss Federal Institute of Technology, Swiss Federal Research Institute WSL, Zurich, Switzerland Lise Van Susteren, Center for Health and the Global Environment, Advisory Board, Harvard School of Public Health, Boston, Massachusetts, United States of America Karina von Schuckmann, L’Institut Francais de Recherche pour l’Exploitation de la Mer, Ifremer, Toulon, France James C. Zachos, Earth and Planetary Science, University of California, Santa Cruz, CA, United States of America We assess climate impacts of global warming using ongoing observations and paleoclimate data. We use Earth’s measured energy imbalance, paleoclimate data, and simple representations of the global carbon cycle and temperature to define emission reductions needed to stabilize climate and avoid potentially disastrous impacts on today’s young people, future generations, and nature. A cumulative industrial-era limit of ~500 GtC fossil fuel emissions and 100 GtC storage in the biosphere and soil would keep climate close to the Holocene range to which humanity and other species are adapted. Cumulative emissions of ~1000 GtC, sometimes associated with 2°C global warming, would spur “slow” feedbacks and eventual warming of 3–4°C with disastrous consequences. Rapid emissions reduction is required to restore Earth’s energy balance and avoid ocean heat uptake that would practically guarantee irreversible effects. Continuation of high fossil fuel emissions, given current knowledge of the consequences, would be an act of extraordinary witting intergenerational injustice. Responsible policymaking requires a rising price on carbon emissions that would preclude emissions from most remaining coal and unconventional fossil fuels and phase down emissions from conventional fossil fuels. Funding came from: NASA Climate Research Funding, Gifts to Columbia University from H.F. (“Gerry”) Lenfest, private philanthropist (no web site, but see http://en.wikipedia.org/wiki/H._F._Lenfest), Jim Miller, Lee Wasserman (Rockefeller Family Fund) (http://www.rffund.org/), Flora Family Foundation (http://www.florafamily.org/), Jeremy Grantham, ClimateWorks and the Energy Foundation provided support for Hansen's Climate Science, Awareness and Solutions program at Columbia University to complete this research and publication. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Integrative Biology Email: [e-mail]