title: Paris Agreement climate proposals need a boost to keep warming well below 2 °C.
abstract: The Paris climate agreement aims at holding global warming to well below 2 degrees Celsius and to "pursue efforts" to limit it to 1.5 degrees Celsius. To accomplish this, countries have submitted Intended Nationally Determined Contributions (INDCs) outlining their post-2020 climate action. Here we assess the effect of current INDCs on reducing aggregate greenhouse gas emissions, its implications for achieving the temperature objective of the Paris climate agreement, and potential options for overachievement. The INDCs collectively lower greenhouse gas emissions compared to where current policies stand, but still imply a median warming of 2.6-3.1 degrees Celsius by 2100. More can be achieved, because the agreement stipulates that targets for reducing greenhouse gas emissions are strengthened over time, both in ambition and scope. Substantial enhancement or over-delivery on current INDCs by additional national, sub-national and non-state actions is required to maintain a reasonable chance of meeting the target of keeping warming well below 2 degrees Celsius.
authors.affiliation: ENE Program, International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.|Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland.
authors.forename: Joeri
authors.initials: J
authors.lastname: Rogelj
authors.affiliation: PBL Netherlands Environmental Assessment Agency, Bilthoven, The Netherlands.
authors.forename: Michel
authors.initials: M
authors.lastname: den Elzen
authors.affiliation: NewClimate Institute, Cologne, Germany.|Environmental Systems Analysis Group, Wageningen University, Wageningen, The Netherlands.
authors.forename: Niklas
authors.initials: N
authors.lastname: Höhne
authors.affiliation: World Resources Institute, Washington DC, USA.
authors.forename: Taryn
authors.initials: T
authors.lastname: Fransen
authors.affiliation: NewClimate Institute, Cologne, Germany.
authors.forename: Hanna
authors.initials: H
authors.lastname: Fekete
authors.affiliation: Energy Research Center, University of Cape Town, Cape Town, South Africa.
authors.forename: Harald
authors.initials: H
authors.lastname: Winkler
authors.affiliation: Universidade Federal do Rio de Janeiro (COPPE/UFRJ), Rio de Janeiro, Brazil.
authors.forename: Roberto
authors.initials: R
authors.lastname: Schaeffer
authors.affiliation: National Center for Climate Change Strategy and International Cooperation, Beijing, China.
authors.forename: Fu
authors.initials: F
authors.lastname: Sha
authors.affiliation: ENE Program, International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.|Graz University of Technology, Graz, Austria.
authors.forename: Keywan
authors.initials: K
authors.lastname: Riahi
authors.affiliation: Australian-German Climate and Energy College, School of Earth Sciences, The University of Melbourne, Melbourne, Victoria, Australia.|PRIMAP Group, Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany.
authors.forename: Malte
authors.initials: M
authors.lastname: Meinshausen
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis; D015986:Confounding Factors, Epidemiologic; D058735:Environmental Policy / Q000331:legislation & jurisprudence* / Q000639:trends*; D057232:Global Warming / Q000331:legislation & jurisprudence* / Q000517:prevention & control*; D006040:Goals; D017752:Greenhouse Effect / Q000331:legislation & jurisprudence / Q000517:prevention & control; D007391:International Cooperation / Q000331:legislation & jurisprudence*; D010297:Paris; D013696:Temperature; D013997:Time Factors; D035501:Uncertainty
chemical_list: D002245:Carbon Dioxide