Young people's burden: requirement of negative CO 2 emissions

• Published in: Earth System Dynamics
• Main Authors: Hansen, James, Sato, Makiko, Kharecha, Pushker, von Schuckmann, Karina, Beerling, David J., Cao, Junji, Marcott, Shaun, Masson-Delmotte, Valérie, Prather, Michael J., Rohling, Eelco J., Shakun, Jeremy, Smith, Pete, Lacis, Andrew, Russell, Gary, Ruedy, Reto
• Other Authors: Climate Science, Awareness and Solutions, Columbia University New York, Mercator Océan, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Service hydrographique et océanographique de la Marine-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Department of Animal and Plant Sciences, University of Sheffield Sheffield, Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), University of California Irvine (UC Irvine), University of California (UC), National Oceanography Centre Southampton (NOC), University of Southampton, Institute of Biological and Environmental Sciences Aberdeen, University of Aberdeen, NASA Goddard Institute for Space Studies (GISS), NASA Goddard Space Flight Center (GSFC), Department of Earth and Environmental Sciences New York
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Ice Sheet
• Online Access: https://hal.science/hal-01584144; https://hal.science/hal-01584144/document; https://hal.science/hal-01584144/file/esd-8-577-2017.pdf; https://doi.org/10.5194/esd-8-577-2017

International audience Global temperature is a fundamental climate metric highly correlated with sea level, which implies that keeping shorelines near their present location requires keeping global temperature within or close to its preindustrial Holocene range. However, global temperature excluding short-term variability now exceeds +1 °C relative to the 1880–1920 mean and annual 2016 global temperature was almost +1.3 °C. We show that global temperature has risen well out of the Holocene range and Earth is now as warm as it was during the prior (Eemian) interglacial period, when sea level reached 6–9 m higher than today. Further, Earth is out of energy balance with present atmospheric composition, implying that more warming is in the pipeline, and we show that the growth rate of greenhouse gas climate forcing has accelerated markedly in the past decade. The rapidity of ice sheet and sea level response to global temperature is difficult to predict, but is dependent on the magnitude of warming. Targets for limiting global warming thus, at minimum, should aim to avoid leaving global temperature at Eemian or higher levels for centuries. Such targets now require "negative emissions", i.e., extraction of CO 2 from the air. If phasedown of fossil fuel emissions begins soon, improved agricultural and forestry practices, including reforestation and steps to improve soil fertility and increase its carbon content, may provide much of the necessary CO 2 extraction. In that case, the magnitude and duration of global temperature excursion above the natural range of the current interglacial (Holocene) could be limited and irreversible climate impacts could be minimized. In contrast, continued high fossil fuel emissions today place a burden on young people to undertake massive technological CO 2 extraction if they are to limit climate change and its consequences. Proposed methods of extraction such as bioenergy with carbon capture and storage (BECCS) or air capture of CO 2 have minimal estimated costs of USD 89–535 trillion ...