Scenarios towards limiting global mean temperature increase below 1.5 °C
05.03.2018
Joeri Rogelj (International Institute for Applied Systems Analysis IIASA, Institute for Atmospheric and Climate Science, ETH Zurich); Alexander Popp (Potsdam Institute for Climate Impact Research PIK, Member of the Leibniz); Katherine V. Calvin (Joint Global Change Research Institute – Pacific Northwest National Laboratory); Gunnar Luderer (Potsdam Institute for Climate Impact Research PIK, Member of the Leibniz); Johannes Emmerling (Fondazione Eni Enrico Mattei, Centro Euro-Mediterraneo sui Cambiamenti Climatici); David Gernaat (PBL Netherlands Environmental Assessment Agency, Copernicus Institute for Sustainable Development – Utrecht University); Shinichiro Fujimori (International Institute for Applied Systems Analysis IIASA, National Institute for Environmental Studies); Jessica Strefler (Potsdam Institute for Climate Impact Research PIK, Member of the Leibniz); Tomoko Hasegawa (International Institute for Applied Systems Analysis IIASA, National Institute for Environmental Studies); Giacomo Marangoni (Fondazione Eni Enrico Mattei, Centro Euro-Mediterraneo sui Cambiamenti Climatici); Volker Krey (International Institute for Applied Systems Analysis IIASA); Elmar Kriegler (Potsdam Institute for Climate Impact Research PIK, Member of the Leibniz); Keywan Riahi (International Institute for Applied Systems Analysis IIASA); Detlef P. van Vuuren (PBL Netherlands Environmental Assessment Agency, Copernicus Institute for Sustainable Development – Utrecht University); Jonathan Doelman (PBL Netherlands Environmental Assessment Agency); Laurent Drouet (Fondazione Eni Enrico Mattei, Centro Euro-Mediterraneo sui Cambiamenti Climatici); Jae Edmonds (Joint Global Change Research Institute, Pacific Northwest National Laboratory); Oliver Fricko (International Institute for Applied Systems Analysis IIASA); Mathijs Harmsen (PBL Netherlands Environmental Assessment Agency, Copernicus Institute for Sustainable Development – Utrecht University); Petr Havlík (International Institute for Applied Systems Analysis IIASA); Florian Humpenöder (Potsdam Institute for Climate Impact Research PIK, Member of the Leibniz); Elke Stehfest (PBL Netherlands Environmental Assessment Agency); Massimo Tavoni (Fondazione Eni Enrico Mattei, Centro Euro-Mediterraneo sui Cambiamenti Climatici, Department of Management, Economics and Industrial Engineering – Politecnico di Milano)
Nature Climate Change, 8, 325–332
The 2015 Paris Agreement calls for countries to pursue efforts to limit global-mean temperature rise to 1.5 °C. The transition pathways that can meet such a target have not, however, been extensively explored. Here we describe scenarios that limit end-of-century radiative forcing to 1.9 W m−2, and consequently restrict median warming in the year 2100 to below 1.5 °C. We use six integrated assessment models and a simple climate model, under different socio-economic, technological and resource assumptions from five Shared Socio-economic Pathways (SSPs). Some, but not all, SSPs are amenable to pathways to 1.5 °C. Successful 1.9 W m−2 scenarios are characterized by a rapid shift away from traditional fossil-fuel use towards large-scale low-carbon energy supplies, reduced energy use, and carbon-dioxide removal. However, 1.9 W m−2 scenarios could not be achieved in several models under SSPs with strong inequalities, high baseline fossil-fuel use, or scattered short-term climate policy. Further research can help policy-makers to understand the real-world implications of these scenarios.