Multisectoral climate impact hotspots in a warming world

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 111; no. 9; pp. 3233 - 3238
• Main Authors: Piontek, Franziska, Müller, Christoph, Pugh, Thomas A. M., Clark, Douglas B., Deryng, Delphine, Elliott, Joshua, de Jesus Colón González, Felipe, Flörke, Martina, Folberth, Christian, Franssen, Wietse, Frieler, Katja, Friend, Andrew D., Gosling, Simon N., Hemming, Deborah, Khabarov, Nikolay, Kim, Hyungjun, Lomas, Mark R., Masaki, Yoshimitsu, Mengel, Matthias, Morse, Andrew, Neumann, Kathleen, Nishina, Kazuya, Ostberg, Sebastian, Pavlick, Ryan, Ruane, Alex C., Schewe, Jacob, Schmid, Erwin, Stacke, Tobias, Tang, Qiuhong, Tessler, Zachary D., Tompkins, Adrian M., Warszawski, Lila, Wisser, Dominik, Schellnhuber, Hans Joachim
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 04.03.2014; National Acad Sciences
• Subjects: Adaptability; Agricultural ecosystems; Agriculture - statistics & numerical data; case studies; climate; Climate change; Climate change adaptation; Climate models; Climatology; Computer Simulation; Conservation of Natural Resources - methods; Crops; Development policy; drought; Ecosystem; Ecosystem models; ecosystems; Environment; Environmental impact; Environmental policy; Geography; Global climate; GLOBAL CLIMATE IMPACTS: A CROSS-SECTOR, MULTI-MODEL ASSESSMENT SPECIAL FEATURE; Global climate models; Global warming; Global Warming - economics; Global Warming - statistics & numerical data; Humans; Malaria; Malaria - epidemiology; Marine; Mathematical models; Modeling; Models, Theoretical; Physical Sciences; Public Policy; risk; Temperature; Tropical regions; uncertainty; Vector-borne diseases; Water Supply - statistics & numerical data; World population; ISI-MIP; coinciding pressures; differential climate impacts
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.1222471110

The impacts of global climate change on different aspects of humanity’s diverse life-support systems are complex and often difficult to predict. To facilitate policy decisions on mitigation and adaptation strategies, it is necessary to understand, quantify, and synthesize these climate-change impacts, taking into account their uncertainties. Crucial to these decisions is an understanding of how impacts in different sectors overlap, as overlapping impacts increase exposure, lead to interactions of impacts, and are likely to raise adaptation pressure. As a first step we develop herein a framework to study coinciding impacts and identify regional exposure hotspots. This framework can then be used as a starting point for regional case studies on vulnerability and multifaceted adaptation strategies. We consider impacts related to water, agriculture, ecosystems, and malaria at different levels of global warming. Multisectoral overlap starts to be seen robustly at a mean global warming of 3 °C above the 1980–2010 mean, with 11% of the world population subject to severe impacts in at least two of the four impact sectors at 4 °C. Despite these general conclusions, we find that uncertainty arising from the impact models is considerable, and larger than that from the climate models. In a low probability-high impact worst-case assessment, almost the whole inhabited world is at risk for multisectoral pressures. Hence, there is a pressing need for an increased research effort to develop a more comprehensive understanding of impacts, as well as for the development of policy measures under existing uncertainty.