STATE OF THE CLIMATE IN 2018 Special Supplement to the Bulletin of the American Meteorological Society Vol. 100, No. 9, September 2019 STATE OF THE CLIMATE IN 2018 Editors Jessica Blunden Derek S. Arndt Chapter Editors Peter Bissolli Martin O. Jeffries Ahira Sánchez-Lugo Howard J. Diamond Tim Li Ted A. Scambos Matthew L. Druckenmiller Rick Lumpkin Carl J. Schreck III Robert J. H. Dunn Ademe Mekonnen Sharon Stammerjohn Catherine Ganter Emily Osborne Diane M. Stanitski Nadine Gobron Jacqueline A. Richter-Menge Kate M. Willett Technical Editor Andrea Andersen BAMS Special Editor for Climate Richard Rosen AMERICAN METEOROLOGICAL SOCIETY COVER CREDITS: FRONT/BACK: © BOB Busey, International Arctic Research Center, University of Alaska Fairbanks Ice-rich permafrost exposed on the face of Itkillik Bluff on the North Slope of Alaska. The bluffs and surrounding ice-rich permafrost have lost large volumes of ice over recent years due to lateral erosion and surface disturbances such as wildfire and climate warming. Members of NASA’s Arctic-Boreal Vulnerability Experiment visit this site annually to collect frozen soil and ground ice for carbon analysis. The team also uses regional airborne and space-borne remote sensing to identify potential volume of major ground ice loss in previously unidentified ice-rich parts of the landscape. How to cite this document: Citing the complete report: Blunden, J. and D. S. Arndt, Eds., 2019: State of the Climate in 2018. Bull. Amer. Meteor. Soc., 100 (9), Si–S305, doi:10.1175/2019BAMSStateoftheClimate.1. Citing a chapter (example): Scambos, T. and S. Stammerjohn Eds., 2019: Antarctica and the Southern Ocean [in “State of the Climate in 2018”]. Bull. Amer. Meteor. Soc., 100 (9), S169–S188, doi:10.1175/2019BAMSStateoftheClimate.1. Citing a section (example): Meijers, A. J., B. Sallée, A. Grey, K. Johnson, K. Arrigo, S. Swart, B. King, and M. Mazloff, 2019: Southern Ocean [in “State of the Climate in 2018”]. Bull. Amer. Meteor. Soc., 100 (9), S181–S185, doi:10.1175/2019BAMSStateoftheClimate.1. EDITOR AND AUTHOR AFFILIATIONS (ALPHABETICAL BY NAME) Ades, M., European Centre for Medium-Range Weather Bernhard, G. H., Biospherical Instruments Inc., San Diego, Forecasts, Reading, United Kingdom California Adler, R., University of Maryland, College Park, Maryland Berrisford, Paul, NCAS-Climate, European Centre for Aldeco, Laura S., Servicio Meteorológico Nacional, Buenos Medium-Range Weather Forecasts, Reading, United Kingdom Aires, Argentina Berry, David I., National Oceanography Centre, Alejandra, G., Instituto Geofísico del Perú, Lima, Perú Southampton, United Kingdom Alfaro, Eric J., Center for Geophysical Research and School of Bettio, Lynette, Bureau of Meteorology, Melbourne, Victoria, Physics, University of Costa Rica, San José, Costa Rica Australia Aliaga-Nestares, Vannia, Servisâo Nacional de Bhatt, U. S., Geophysical Institute, University of Alaska Meteorología e Hidrología del Perú, Lima, Perú Fairbanks, Fairbanks, Alaska Allan, Richard P., University of Reading, Reading, United Biskaborn, B. K., Alfred Wegener Institute Helmholtz Centre Kingdom for Polar and Marine Research, Potsdam, Germany Allan, Rob, Met Office Hadley Centre, Exeter, United Kingdom Bissolli, Peter, Deutscher Westterdienst, WMO RA VI Alves, Lincoln M., Centro de Ciencias do Sistema Terrestre, Regional Climate Centre Network, Offenbach, Germany Instituto Nacional de Pesquisas Espaciais, Cachoeira Paulista, Bjella, Kevin L., Cold Regions Research and Engineering Sao Paulo, Brazil Laboratory (CRREL), Fairbanks, Alaska Amador, Jorge A., Center for Geophysical Research and Bjerke, J. K., Norwegian Institute for Nature Research, School of Physics, University of Costa Rica, San José, Costa Tromsø, Norway Rica Blake, Eric S., NOAA/NWS National Hurricane Center, Andersen, J. K., Geological Survey of Denmark and Miami, Florida Greenland, Copenhagen, Denmark Blenkinsop, Stephen, School of Engineering, Newcastle Anderson, John, Department of Atmospheric and Planetary University, Newcastle-upon-Tyne, United Kingdom Science, Hampton University, Hampton, Virginia Blunden, Jessica, NOAA/NESDIS National Centers for Arndt, Derek S., NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Environmental Information, Asheville, North Carolina Bock, Olivier, Paris Institute of Globe Physics, Université Paris Arosio, C., University of Bremen, Bremen, Germany Diderot, Sorbonne Paris Cité, Paris, France Arrigo, Kevin, Department of Earth System Science, Stanford Bosilovich, Michael G., Global Modeling and Assimilation University, Stanford, California Office, NASA Goddard Space Flight Center, Greenbelt, Azorin-Molina, César, Regional Climate Group, Department Maryland of Earth Sciences, University of Gothenburg, Gothenburg, Boucher, Olivier, Sorbonne Université, Paris, France Sweden; Centro de Investigaciones sobre Desertificación – Box, J. E., Geological Survey of Denmark and Greenland, Spanish National Research Council, Moncada (Valencia), Spain Copenhagen, Denmark Bardin, M. Yu, Yu. A. Izrael Institute of Global Climate and Boyer, Tim, NOAA/NESDIS National Centers for Ecology, and Institute of Geography, Russian Academy of Environmental Information, Silver Spring, Maryland Sciences, Russia Braathen, Geir, WMO Atmospheric Environment Research Barichivich, Jonathan, Instituto de Geografía, Pontificia Division, Geneva, Switzerland Universidad Católica de Valparaíso, Valparaíso, Chile Bringas, Francis. G., NOAA/OAR Atlantic Oceanographic Barreira, Sandra, Argentine Naval Hydrographic Service, and Meteorological Laboratory (AOML), Miami, Florida Buenos Aires, Argentina Bromwich, David. H., Byrd Polar and Climate Research Baxter, Stephen, NOAA/NWS Climate Prediction Center, Center, The Ohio State University, Columbus, Ohio College Park, Maryland Brown, Alrick, Department of Physics, The University of the Beck, H. E., Department of Civil and Environmental West Indies, Jamaica Engineering, Princeton University, Princeton, New Jersey Brown, R., Climate Research Division, Environment and Becker, Andreas, Global Precipitation Climatology Centre, Climate Change Canada, Montréal, Quebec, Canada Deutscher Wetterdienst, Offenbach am Main., Germany Brown, Timothy J., Western Regional Climate Center, Bell, Gerald D., NOAA/NWS Climate Prediction Center, Desert Research Institute, Reno, NV College Park, Maryland Buehler, S. A., Universität Hamburg, Hamburg, Germany Bellouin, Nicolas, University of Reading, Reading, United Cáceres, Luis, Instituto Nacional de Meteorología e Hidrología Kingdom de Ecuador, Ecuador Belmont, M., Seychelles National Meteorological Services, Calderón, Blanca, Center for Geophysical Research, Pointe Larue, Mahé, Seychelles University of Costa Rica, San José, Costa Rica Benedetti, Angela, European Centre for Medium-Range Camargo, Suzana J., Lamont-Doherty Earth Observatory, Weather Forecasts, Reading, United Kingdom Columbia University, Palisades, New York Benedict, Imme, Meteorology and Air Quality Group, Campbell, Jayaka D., Department of Physics, The University Wageningen University and Research, Wageningen, of the West Indies, Jamaica Netherlands STATE OF THE CLIMATE IN 2018 SEPTEMBER 2019 | Si Campos Diaz, Diego A., Dirección Meteorológica de Chile, Davis, Sean M., Cooperative Institute for Research in Santiago de Chile, Chile Environmental Sciences, University of Colorado Boulder, and Cappelen, J., Danish Meteorological Institute, Copenhagen, NOAA/OAR Earth System Research Laboratory, Boulder, Denmark Colorado Carrea, Laura, Department of Meteorology, University of de Eyto, Elvira, Marine Institute, Furnace, Newport, Ireland Reading, Reading, United Kingdom de Jeu, Richard A. M., VanderSat B.V., Haarlem, Netherlands Carrier, Seth B., National Institute of Water and Atmospheric De Laat, Jos, Royal Netherlands Meteorological Institute Research, Ltd., Auckland, New Zealand (KNMI), DeBilt, Netherlands Carter, Brendan R., Joint Institute for the Study of the Decharme, B., Centre National de Recherches Atmosphere and Ocean, University of Washington, and Météorologiques, France NOAA/OAR Pacific Marine Environmental Laboratory, DeGasperi, Curtis L., King County Water and Land Seattle, Washington Resources Division, Seattle, Washington Castro, Anabel Y., Servicio Nacional de Meteorología e Degenstein, Doug, University of Saskatchewan, Saskatoon, Hidrología del Perú, Lima, Perú Saskatchewan Canada Cetinić, Ivona, NASA Goddard Space Flight Center, Demircan, Mesut, Turkish State Meteorological Service, Greenbelt, Maryland, and Universities Space Research Ankara, Turkey Association, Columbia, Maryland Derksen, C., Climate Research Division, Environment and Chambers, Don P., College of Marine Science, University of Climate Change Canada,Downsview, Ontario, Canada South Florida, St. Petersburg, Florida Dhurmea, K. R., Mauritius Meteorological Service, Vacoas, Chen, Lin., Institute for Climate and Application Research Mauritius (ICAR)/KLME/ILCEC/CIC-FEMD, Nanjing University of Di Girolamo, Larry, University of Illinois at Urbana- Information Science and Technology, Nanjing, China Champaign, Champaign, Illinois Cheng, Lijing, International Center for Climate and Diamond, Howard J., NOAA/OAR Air Resources Environment Sciences, Institute of Atmospheric Physics, Laboratory, College Park, Maryland Chinese Academy of Sciences, Beijing, China Diaz, Eliecer, Instituto de Hidrología de Meteorología y Cheng, Vincent. Y. S., Environment and Climate Change Estudios Ambientales de Colombia (IDEAM), Bogotá, Canada, Toronto, Ontario,