Abstract
In 2017, the dominant greenhouse gases released into Earth's atmosphere-carbon dioxide, methane, and nitrous oxide-reached new record highs. The annual global average carbon dioxide concentration at Earth's surface for 2017 was 405.0 ± 0.1 ppm, 2.2 ppm greater than for 2016 and the highest in the modern atmospheric measurement record and in ice core records dating back as far as 800 000 years. The global growth rate of CO2 has nearly quadrupled since the early 1960s. With ENSO-neutral conditions present in the central and eastern equatorial Pacific Ocean during most of the year and weak La Niña conditions notable at the start and end, the global temperature across land and ocean surfaces ranked as the second or third highest, depending on the dataset, since records began in the mid-to-late 1800s. Notably, it was the warmest non-El Niño year in the instrumental record. Above Earth's surface, the annual lower tropospheric temperature was also either second or third highest according to all datasets analyzed. The lower stratospheric temperature was about 0.2°C higher than the record cold temperature of 2016 according to most of the in situ and satellite datasets. Several countries, including Argentina, Uruguay, Spain, and Bulgaria, reported record high annual temperatures. Mexico broke its annual record for the fourth consecutive year. On 27 January, the temperature reached 43.4°C at Puerto Madryn, Argentina-the highest temperature recorded so far south (43°S) anywhere in the world. On 28 May in Turbat, western Pakistan, the high of 53.5°C tied Pakistan's all-time highest temperature and became the world-record highest temperature for May. In the Arctic, the 2017 land surface temperature was 1.6°C above the 1981-2010 average, the second highest since the record began in 1900, behind only 2016. The five highest annual Arctic temperatures have all occurred since 2007. Exceptionally high temperatures were observed in the permafrost across the Arctic, with record values reported in much of Alaska and northwestern Canada. In August, high sea surface temperature (SST) records were broken for the Chukchi Sea, with some regions as warm as +11°C, or 3° to 4°C warmer than the longterm mean (1982-present). According to paleoclimate studies, today's abnormally warm Arctic air and SSTs have not been observed in the last 2000 years. The increasing temperatures have led to decreasing Arctic sea ice extent and thickness. On 7 March, sea ice extent at the end of the growth season saw its lowest maximum in the 37-year satellite record, covering 8% less area than the 1981-2010 average. The Arctic sea ice minimum on 13 September was the eighth lowest on record and covered 25% less area than the long-term mean. Preliminary data indicate that glaciers across the world lost mass for the 38th consecutive year on record; the declines are remarkably consistent from region to region. Cumulatively since 1980, this loss is equivalent to slicing 22 meters off the top of the average glacier. Antarctic sea ice extent remained below average for all of 2017, with record lows during the first four months. Over the continent, the austral summer seasonal melt extent and melt index were the second highest since 2005, mostly due to strong positive anomalies of air temperature over most of the West Antarctic coast. In contrast, the East Antarctic Plateau saw record low mean temperatures in March. The year was also distinguished by the second smallest Antarctic ozone hole observed since 1988. Across the global oceans, the overall long-term SST warming trend remained strong. Although SST cooled slightly from 2016 to 2017, the last three years produced the three highest annual values observed; these high anomalies have been associated with widespread coral bleaching. The most recent global coral bleaching lasted three full years, June 2014 to May 2017, and was the longest, most widespread, and almost certainly most destructive such event on record. Global integrals of 0-700-m and 0-2000-m ocean heat content reached record highs in 2017, and global mean sea level during the year became the highest annual average in the 25-year satellite altimetry record, rising to 77 mm above the 1993 average. In the tropics, 2017 saw 85 named tropical storms, slightly above the 1981-2010 average of 82. The North Atlantic basin was the only basin that featured an above-normal season, its seventh most active in the 164-year record. Three hurricanes in the basin were especially notable. Harvey produced record rainfall totals in areas of Texas and Louisiana, including a storm total of 1538.7 mm near Beaumont, Texas, which far exceeds the previous known U.S. tropical cyclone record of 1320.8 mm. Irma was the strongest tropical cyclone globally in 2017 and the strongest Atlantic hurricane outside of the Gulf of Mexico and Caribbean on record with maximum winds of 295 km h-1. Maria caused catastrophic destruction across the Caribbean Islands, including devastating wind damage and flooding across Puerto Rico. Elsewhere, the western North Pacific, South Indian, and Australian basins were all particularly quiet. Precipitation over global land areas in 2017 was clearly above the long-term average. Among noteworthy regional precipitation records in 2017, Russia reported its second wettest year on record (after 2013) and Norway experienced its sixth wettest year since records began in 1900. Across India, heavy rain and flood-related incidents during the monsoon season claimed around 800 lives. In August and September, above-normal precipitation triggered the most devastating floods in more than a decade in the Venezuelan states of Bolívar and Delta Amacuro. In Nigeria, heavy rain during August and September caused the Niger and Benue Rivers to overflow, bringing floods that displaced more than 100 000 people. Global fire activity was the lowest since at least 2003; however, high activity occurred in parts of North America, South America, and Europe, with an unusually long season in Spain and Portugal, which had their second and third driest years on record, respectively. Devastating fires impacted British Columbia, destroying 1.2 million hectares of timber, bush, and grassland, due in part to the region's driest summer on record. In the United States, an extreme western wildfire season burned over 4 million hectares; the total costs of $18 billion tripled the previous U.S. annual wildfire cost record set in 1991.
Original language | English |
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Pages (from-to) | Si-S310 |
Journal | Bulletin of the American Meteorological Society |
Volume | 99 |
Issue number | 8 |
Publication status | Published - 1 Aug 2018 |
Funding
Becker, Andreas, Global Precipitation Climatology Centre, Deutscher Wetterdienst, Offenbach, Germany Bedka, Kristopher M., NASA Langley Research Center, Hampton, Virginia Behe, Carolina, Inuit Circumpolar Council Alaska, Anchorage, Alaska Bell, Gerald D., NOAA/NWS Climate Prediction Center, College Park, Maryland Bellouin, Nicolas, University of Reading, Reading, United Kingdom Belmont, M., Seychelles National Meteorological Services, Pointe Larue, Mahé, Seychelles Benedetti, Angela, European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom Bernhard , G. H., Biospherical Instruments, San Diego, California Berrisford, Paul, European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom Berry, David I., National Oceanography Centre, Southampton, United Kingdom Bhatt, U. S., Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska Bissolli, Peter, Deutscher Wetterdienst, WMO RA VI Regional Climate Centre Network, Offenbach, Germany Bjerke, J., Norwegian Institute for Nature Research, Tromsø, Norway Blake, Eric S., NOAA/NWS National Hurricane Center, Miami, Florida Blenkinsop, Stephen, School of Engineering, Newcastle University, Newcastle-upon-Tyne, United Kingdom Blunden, Jessica, NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Bolmgren, K., Swedish University of Agricultural Sciences, Uppsala, Sweden Bosilovich, Michael G., Global Modelling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, Maryland Boucher, Olivier, Institut Pierre-Simon Laplace, CNRS/UPMC, Paris, France Bouchon, Marilú, Instituto del Mar del Perú, Callao, Perú Box, J. E., Geological Survey of Denmark and Greenland, Copenhagen, Denmark Boyer, Tim, NOAA/NESDIS National Centers for Environmental Information, Silver Spring, Maryland Braathen, Geir O., WMO Atmospheric Environment Research Division, Geneva, Switzerland Bromwich, David H., Byrd Polar and Climate Research Center, The Ohio State University, Columbus, Ohio Brown, R., Climate Research Division, Environment and Climate Change Canada, Downsview, Ontario, Canada Buehler, S., Universitaet Hamburg, Hamburg, Germany Bulygina, Olga N., Russian Institute for Hydrometeorological Information, Obninsk, Russia Burgess, D., Geological Survey of Canada, Ottawa, Ontario, Canada Calderón, Blanca, Center for Geophysical Research, University of Costa Rica, San José, Costa Rica Camargo, Suzana J., Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York Campbell, Ethan C., School of Oceanography, University of Washington, Seattle, Washington Campbell, Jayaka D., Department of Physics, The University of the West Indies, Jamaica Cappelen, J., Danish Meteorological Institute, Copenhagen, Denmark Carrea, Laura, Department of Meteorology, University of Reading, Reading, United Kingdom Carter, Brendan R., Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, and NOAA/OAR Pacific Marine Environmental Laboratory, Seattle, Washington Castro, Anabel, Servicio Nacional de Meteorología e Hidrología del Perú, Lima, Perú Chambers, Don P., College of Marine Science, University of South Florida, St. Petersburg, Florida Cheng, Lijing, International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China Christiansen, Hanne H., Geology Department, University Centre in Svalbard, Longyearbyen, Norway Christy, John R., University of Alabama in Huntsville, Huntsville, Alabama Chung, E.-S., Rosenstiel School of Marine and Atmospheric Science, University of Miami, Key Biscane, Miami, Florida Clem, Kyle R., Institute of Earth, Ocean, and Atmospheric Sciences, Rutgers, the State University of New Jersey, New Brunswick, New Jersey Coelho, Caio A.S., CPTEC/INPE Center for Weather Forecasts and Climate Studies, Cachoeira Paulista, Brazil Coldewey-Egbers, Melanie, German Aerospace Center (DLR) Oberpfaffenhofen, Wessling, Germany Colwell, Steve, British Antarctic Survey, Cambridge, United Kingdom Cooper, Owen R., Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, and NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Copland, L., Department of Geography, University of Ottawa, Ottawa, Ontario, Canada Costanza, Carol, Antarctic Meteorological Research Center and Space Science and Engineering Center, University of Wisconsin-Madison, Madison, Wisconsin Covey, Curt, Lawrence Livermore National Laboratory, Livermore, California Coy, Lawrence, Science Systems and Applications, Inc., NASA Goddard Space Flight Center, Greenbelt, Maryland Cronin, T., U.S. Geological Survey, Reston, Virginia Crouch, Jake, NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Cruzado, Luis, Servicio Nacional de Meteorología e Hidrología del Perú, Lima, Perú Daniel, Raychelle, The Pew Charitable Trusts, Washington, D.C. Davis, Sean M., Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, and NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Davletshin, S. G., Russian Institute for Hydrometeorological Information, Obninsk, Russia de Eyto, Elvira, Marine Institute, Newport, Ireland de Jeu, Richard A. M., EODC GmbH, Vienna, Austria De La Cour, Jacqueline L., NOAA/NESDIS Coral Reef Watch, College Park, Maryland, and Global Science and Technology, Inc., Greenbelt, Maryland de Laat, Jos, Royal Netherlands Meteorological Institute (KNMI), DeBilt, Netherlands DeGasperi, Curtis L., King County Water and Land Resources Division, Seattle, Washington Degenstein, Doug, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Deline, P., EDYTEM Lab, University Savoie Mont Blanc, Chambéry, France Demircan, Mesut, Turkish State Meteorological Service, Ankara, Turkey Derksen, C., Climate Research Division, Environment and Climate Change Canada, Downsview, Ontario, Canada Dewitte, Boris, Centro de Estudios Avanzado en Zonas Áridas, and Universidad Católica del Norte, Coquimbo, Chile, and Laboratoire d’Etudes en Géophysique et Océanographie Spatiales, Toulouse, France Dhurmea, R., Mauritius Meteorological Service, Vacoas, Mauritius Di Girolamo, Larry, University of Illinois at Urbana– Champaign, Urbana, Illinois Diamond, Howard J., NOAA/OAR Air Resources Laboratory, Silver Spring, Maryland Dickerson, C., Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia Dlugokencky, Ed J., NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Dohan, Kathleen, Earth and Space Research, Seattle, Washington Dokulil, Martin T., Research Institute for Limnology, University of Innsbruck, Mondsee, Austria Dolman, A. Johannes, Department of Earth Sciences, Earth and Climate Cluster, VU University Amsterdam, Amsterdam, Netherlands Domingues, Catia M., Institute for Marine and Antarctic Studies, University of Tasmania, Antarctic Climate and Ecosystems Cooperative Research Centre, and Australian Research Council’s Centre of Excellence for Climate System Science, Hobart, Tasmania, Australia Domingues, Ricardo, Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, Florida Donat, Markus G., Climate Change Research Centre, University of New South Wales, Sydney, New South Wales, Australia Dong, Shenfu, NOAA/OAR Atlantic Oceanographic and Meteorological Laboratory, and Cooperative Institute for Marine and Atmospheric Science, Miami, Florida Dorigo, Wouter A., Department of Geodesy and Geoinformation, Vienna University of Technology, Vienna, Austria Drozdov, D. S., Earth Cryosphere Institute, and Tyumen State University, Tyumen, Russia Dunn, Robert J. H., Met Office Hadley Centre, Exeter, United Kingdom Durre, Imke, NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Dutton, Geoff S., Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, and NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Eakin, C. Mark, NOAA/NESDIS Coral Reef Watch, College Park, Maryland ElKharrim, M., Direction de la Météorologie Nationale Maroc, Rabat, Morocco Elkins, James W., NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Epstein, H. E., Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia Espinoza, Jhan C., Instituto Geofisico del Perú, Lima, Perú Famiglietti, James S., Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California Farmer, J., Department of Geosciences, Princeton University, Princeton, New Jersey Farrell, S., Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland Fauchald, P., Norwegian Institute for Nature Research, Tromsø, Norway Fausto, R. S., Geological Survey of Denmark and Greenland, Copenhagen, Denmark Feely, Richard A., NOAA/OAR Pacific Marine Environmental Laboratory, Seattle, Washington Feng, Z., Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington Fenimore, Chris, NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Fettweis, X., University of Liège, Liège, Belgium Fioletov, Vitali E., Environment and Climate Change Canada, Toronto, Ontario, Canada Flemming, Johannes, European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom Fogt, Ryan L., Department of Geography, Ohio University, Athens, Ohio Folland, Chris, Met Office Hadley Centre, Exeter, and School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom, and Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden, and International Centre for Applied Climate Sciences, University of Southern Queensland, Toowoomba, Queensland, Australia Forbes, B. C., Arctic Centre, University of Lapland, Rovaniemi, Finland Foster, Michael J., Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin–Madison, Madison, Wisconsin Francis, S. D., National Weather Forecasting and Climate Research Centre, Nigerian Meteorological Agency, Abuja, Nigeria Franz, Bryan A., NASA Goddard Space Flight Center, Greenbelt, Maryland Frey, Richard A., Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin–Madison, Madison, Wisconsin Frith, Stacey M., Science Systems and Applications, Inc. and NASA Goddard Space Flight Center, Greenbelt, Maryland Froidevaux, Lucien, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California Ganter, Catherine, Bureau of Meteorology, Melbourne, Victoria, Australia Geiger, Erick F., NOAA/NESDIS Coral Reef Watch, College Park, Maryland, and Global Science and Technology, Inc., Greenbelt, Maryland Gerland, S., Norwegian Polar Institute, Fram Centre, Tromsø, Norway Gilson, John, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California Gobron, Nadine, European Commission, Joint Research Centre, Ispra, Italy Goldenberg, Stanley B., NOAA/OAR/AOML Hurricane Research Division, Miami, Florida Gomez, Andrea M., NOAA/NESDIS Coral Reef Watch, College Park, Maryland, and Ecosystem Science Lab and NOAA-CREST, New York, New York Goni, Gustavo, NOAA/OAR Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida Grooß, Jens-Uwe, Forschungszentrum Jülich, Jülich, Germany Gruber, Alexander, Department of Geodesy and Geoinformation, Vienna University of Technology, Vienna, Austria; Department of Earth and Environmental Sciences, KU Leuven, Heverlee, Belgium Guard, Charles “Chip” P., NOAA/NWS Weather Forecast Office, Guam Gugliemin, Mario, Department of Theoretical and Applied Sciences, Insubria University, Varese, Italy Gupta, S. K., Science Systems and Applications, Inc., Hampton, Virginia Gutiérrez, Dimitri, Instituto del Mar del Perú, Callao, Perú Haas, C., Alfred Wegener Institute, Helmholtz Centre for Polar and Martine Research, Bremerhaven, Germany Hagos, S., Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington Hahn, Sebastian, Department of Geodesy and Geoinformation, Vienna University of Technology, Vienna, Austria Haimberger, Leo, Department of Meteorology and Geophysics, University of Vienna, Vienna, Austria Ialongo, Iolanda, Finnish Meteorological Institute, Helsinki, Finland Ibrahim, M. M., Department of Meteorology, Al-Azhar University, Egypt Ijampy, J. A., Nigerian Meteorological Agency, Abuja, Nigeria Inness, Antje, European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom Isaac, Victor, Environment and Climate Change Canada, Toronto, Ontario, Canada Isaksen, K., Norwegian Meteorological Institute, Blindern, Oslo, Norway Ishii, Masayoshi, Climate Research Department, Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Japan Jacobs, Stephanie J., Bureau of Meteorology, Melbourne, Victoria, Australia Jeffries, Martin O., Office of Naval Research, Arlington, Virginia Jevrejeva, Svetlana, National Oceanography Centre, Liverpool, United Kingdom Jiménez, C., Estellus, Paris, France Jin, Xiangze, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts John, Viju, EUMETSAT, Darmstadt, Germany, and Met Office Hadley Centre, Exeter, United Kingdom Johns, William E., Rosenstiel School of Marine and Atmospheric Science, Miami, Florida Johnsen, Bjørn, Norwegian Radiation Protection Authority, Østerås, Norway Johnson, Bryan, NOAA/OAR Earth System Research Laboratory, Global Monitoring Division, and University of Colorado Boulder, Boulder, Colorado Johnson, Gregory C., NOAA/OAR Pacific Marine Environmental Laboratory, Seattle, Washington Johnson, Kenneth S., Monterey Bay Aquarium Research Institute, Moss Landing, California Jones, Philip D., Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom Jumaux, Guillaume, Météo France, Direction Interrégionale pour l’Océan Indien, Réunion Kabidi, Khadija, Direction de la Météorologie Nationale Maroc, Rabat, Morocco Kaiser, J. W., Max Planck Institute for Chemistry, Mainz, Germany Karaköylü, Erdem M., NASA Goddard Space Flight Center, Greenbelt, Maryland, and Science Application International Corporation, Beltsville, Maryland Kato, Seiji, NASA Langley Research Center, Hampton, Virginia Kazemi, A., Islamic Republic of Iranian Meteorological Organization, Iran Keller, Linda M., Department of Atmospheric and Oceanic Sciences, University of Wisconsin–Madison, Madison, Wisconsin Kennedy, John, Met Office Hadley Centre, Exeter, United Kingdom Kerr, Kenneth, Trinidad and Tobago Meteorological Service, Piarco, Trinidad Khan, M. S., Geological Survey of Denmark and Greenland, Copenhagen, Denmark Kholodov, A. L., Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska Khoshkam, Mahbobeh, Islamic Republic of Iranian Meteorological Organization, Iran Killick, Rachel, Met Office Hadley Centre, Exeter, United Kingdom Kim, Hyungjun, Institute of Industrial Science, University of Tokyo, Japan Kim, S.-J., Korea Polar Research Institute, Incheon, Republic of Korea Klotzbach, Philip J., Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado Knaff, John A., NOAA/NESDIS Center for Satellite Applications and Research, Fort Collins, Colorado Kohler, J., Norwegian Polar Institute, Tromsø, Norway Korhonen, Johanna, Freshwater Centre, Finnish Environment Institute (SYKE), Helsinki, Finland Korshunova, Natalia N., All-Russian Research Institute of Hydrometeorological Information - World Data Center, Obninsk, Russia Kramarova, Natalya, NASA Goddard Space Flight Center, Greenbelt, Maryland Kratz, D. P., NASA Langley Research Center, Hampton, Virginia Kruger, Andries, South African Weather Service, Pretoria, South Africa Kruk, Michael C., ERT, Inc., NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Krumpen, T., Alfred Wegener Institute, Helmholtz Centre for Polar and Martine Research, Bremerhaven, Germany Ladd, C., NOAA/OAR Pacific Marine Environmental Laboratory, Seattle, Washington Lakatos, Mónika, Climatology Division, Hungarian Meteorological Service, Budapest, Hungary Lakkala, Kaisa, Finnish Meteorological Institute, Arctic Research Centre, Sodankylä, Finland Lander, Mark A., University of Guam, Mangilao, Guam Landschützer, Peter, Max Planck Institute for Meteorology, Hamburg, Germany Landsea, Chris W., NOAA/NWS National Hurricane Center, Miami, Florida Lankhorst, Matthias, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California Lavado-Casimiro, Waldo, Servicio Nacional de Meteorología e Hidrología del Perú, Lima, Perú Lazzara, Matthew A., Department of Physical Sciences, School of Arts and Sciences, Madison Area Technical College, and Space Science and Engineering Center, University of Wisconsin–Madison, Madison, Wisconsin Lee, S.-E., Korea Meteorological Administration, South Korea Lee, T. C., Hong Kong Observatory, Hong Kong, China Leuliette, Eric, NOAA/NWS NCWCP Laboratory for Satellite Altimetry, College Park, Maryland L’Heureux, Michelle, NOAA/NWS Climate Prediction Center, College Park, Maryland Li, Bailing, Hydrological Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland; Earth System Science Interdisciplinary Center, University of Maryland, College Park, Maryland Li, Tim, Department of Atmospheric Sciences, Universtiy of Hawaii, Honolulu, Hawaii Lieser, Jan L., Antarctic Climate and Ecosystems Cooperative Research Centre and Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia Lin, I.-I., National Taiwan University, Taipei, Taiwan Liu, Gang, NOAA/NESDIS Coral Reef Watch, College Park, Maryland, and Global Science and Technology, Inc., Greenbelt, Maryland Liu, Hongxing, Department of Geography, University of Cincinnati, Cincinnati, Ohio Locarnini, Ricardo, NOAA/NESDIS National Centers for Environmental Information, Silver Spring, Maryland Loeb, Norman G., NASA Langley Research Center, Hampton, Virginia Long, Craig S., NOAA/NWS National Centers for Environmental Prediction, College Park, Maryland López, Luis A., Instituto de Hidrología, Meteorología y Estudios Ambientales de Colombia, Bogotá, Colombia Lorrey, Andrew M., National Institute of Water and Atmospheric Research, Ltd., Auckland, New Zealand Loyola, Diego, German Aerospace Center (DLR) Oberpfaffenhofen, Wessling, Germany Lumpkin, Rick, NOAA/OAR Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida Luo, Jing-Jia, Australian Bureau of Meteorology, Melbourne, Victoria, Australia Luojus, K., Finnish Meteorological Institute, Helsinki, Finland Luthcke, S., NASA Goddard Space Flight Center, Greenbelt, Maryland Lyman, John M., NOAA/OAR Pacific Marine Environmental Laboratory, Seattle, Washington, and Joint Institute for Marine and Atmospheric Research, University of Hawaii, Honolulu, Hawaii Macias-Fauria, M., School of Geography and the Environment, University of Oxford, Oxford, United Kingdom Malkova, G. V., Earth Cryosphere Institute, Tyumen Science Center, Tyumen, Russia Manney, Gloria L., NorthWest Research Associates, and New Mexico Institute of Mining and Technology, Socorro, New Mexico Marcellin, Vernie, Dominica Meteorological Service, Dominica Marchenko, S. S., Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska Marengo, José A., Centro Nacional de Monitoramento e Alertas aos Desastres Naturais, Cachoeira Paulista, Sao Paulo, Brazil Marín, Dora, Servicio Nacional de Meteorología e Hidrología de Perú, Lima, Perú Marra, John J., NOAA/NESDIS National Centers for Environmental Information, Honolulu, Hawaii Marsh, Benjamin L., NOAA/NESDIS Coral Reef Watch, College Park, Maryland, and ReefSense Pty Ltd, Townsville, Queensland, Australia Marszelewski, Wlodzimierz, Department of Hydrology and Water Management, Nicolaus Copernicus University, Toruń, Poland Martens, B., Laboratory of Hydrology and Water Management, Ghent University, Ghent, Belgium Martin, A., Department of Zoology, University of Oxford, Oxford, United Kingdom Martínez, Alejandra G., Instituto Geofísico del Perú, Lima, Perú Martínez-Güingla, Rodney, Centro Internacional para la Investigación del Fenómeno de El Niño, Guayaquil, Ecuador Martínez-Sánchez, Odalys, NOAA/NWS San Juan, Puerto Rico Massom, Robert A., Australian Antarctic Division, and Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Tasmania, Australia May, Linda, Centre for Ecology and Hydrology, Edinburgh, United Kingdom Mayer, Michael, Department of Meteorology and Geophysics, University of Vienna, Vienna, Austria; European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom Mazloff, Matthew, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California McBride, Charlotte, South African Weather Service, Pretoria, South Africa McCabe, M. F., Water Desalination and Reuse Center, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia McCarthy, Mark, Met Office Hadley Centre, Exeter, United Kingdom McVicar, Tim R., CSIRO Land and Water Flagship, Canberra, Australian Capital Territory, and Australian Research Council Centre of Excellence for Climate System Science, Sydney, New South Wales, Australia Mears, Carl A., Remote Sensing Systems, Santa Rosa, California Meier, W., National Snow and Ice Data Center, University of Colorado, Boulder, Boulder, Colorado Meijers, Andrew J. S., British Antarctic Survey, Cambridge, United Kingdom Mekonnen, Ademe, Department of Energy and Environmental Systems, North Carolina A & T State University, Greensboro, North Carolina Mengistu Tsidu, G., Department of Earth and Environmental Sciences, Botswana International University of Science and Technology, Palapye, Botswana, and Department of Physics, Addis Ababa University, Addis Ababa, Ethiopia Menzel, W. Paul, Space Science and Engineering Center, University of Wisconsin–Madison, Madison, Wisconsin Merchant, Christopher J., Department of Meteorology, University of Reading, Reading, and National Centre for Earth Observation, University of Reading, Reading, United Kingdom Meredith, Michael P., British Antarctic Survey, Cambridge, United Kingdom Merrifield, Mark A., Joint Institute for Marine and Atmospheric Research, University of Hawaii, Honolulu, Hawaii Miller, Ben, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, and NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Miralles, Diego G., Laboratory of Hydrology and Water Management, Ghent University, Ghent, Belgium Mitchum, Gary T., College of Marine Science, University of South Florida, St. Petersburg, Florida Mitro, Sukarni, Meteorological Service Suriname, Paramaribo, Suriname Moat, Ben, National Oceanography Centre, Southampton, United Kingdom Mochizuki, Y., Tokyo Climate Center, Japan Meteorological Agency, Japan Monselesan, Didier, CSIRO Oceans and Atmosphere, Hobart, Tasmania, Australia Montzka, Stephen A., NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Mora, Natalie, Center for Geophysical Research and School of Physics, University of Costa Rica, San José, Costa Rica Morice, Colin, Met Office Hadley Centre, Exeter, United Kingdom Mosquera-Vásquez, Kobi, Instituto Geofísico del Perú, Lima, Perú Mostafa, Awatif E., Department of Seasonal Forecast and Climate Research, Cairo Numerical Weather Prediction, Egyptian Meteorological Authority, Cairo, Egypt Mote, T., Department of Geography, University of Georgia, Athens, Georgia Mudryk, L., Climate Research Division, Environment and Climate Change Canada, Downsview, Ontario, Canada Mühle, Jens, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California Mullan, A. Brett, National Institute of Water and Atmospheric Research, Ltd., Wellington, New Zealand Müller, Rolf, Forschungszentrum Jülich, Jülich, Germany Myneni, R., Department of Earth and Environment, Boston University, Boston, Massachusetts Nash, Eric R., Science Systems and Applications, Inc., Lanham, Maryland Nerem, R. Steven, Colorado Center for Astrodynamics Research, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado Newman, L., SOOS International Project Office, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia. Newman, Paul A., NASA Goddard Space Flight Center, Greenbelt, Maryland Nielsen-Gammon, John W., Texas A&M University, College Station, Texas Nieto, Juan José, Centro Internacional para la Investigación del Fenómeno de El Niño, Guayaquil, Ecuador Noetzli, Jeannette, WSL Institute for Snow and Avalanche Research, Davos, Switzerland Noll, Ben E., National Institute of Water and Atmospheric Research, Ltd., (NIWA), Auckland, New Zealand O’Neel, S., USGS, Alaska Science Center, Anchorage, Alaska Osborn, Tim J., Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom Osborne, Emily, NOAA/OAR Arctic Research Program, Silver Spring, Maryland Overland, J., NOAA/OAR Pacific Marine Environmental Laboratory, Seattle, Washington Oyunjargal, Lamjav, Hydrology and Environmental Monitoring, Institute of Meteorology and Hydrology, National Agency for Meteorology, Ulaanbaatar, Mongolia Park, T., Department of Earth and Environment, Boston University, Boston, Massachusetts Pasch, Richard J., NOAA/NWS National Hurricane Center, Miami, Florida Pascual-Ramírez, Reynaldo, National Meteorological Service of Mexico, Mexico Pastor Saavedra, Maria Asuncion, Agencia Estatal de Meteorología, Madrid, Spain Paterson, Andrew M., Dorset Environmental Science Centre, Ontario Ministry of the Environment and Climate Change, Dorset, Ontario, Canada Paulik, Christoph, VanderSat B.V., Haarlem, the Netherlands Pearce, Petra R., National Institute of Water and Atmospheric Research, Ltd., Auckland, New Zealand Peltier, Alexandre, Météo-France en Nouvelle-Cáledonie, Noumea, Caledonia Pelto, Mauri S., Nichols College, Dudley, Massachusetts Peng, Liang, State University of New York, Albany, New York Perkins-Kirkpatrick, Sarah E., Climate Change Research Centre, University of New South Wales, Sydney, New South Wales, Australia Perovich, Don, Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire Petropavlovskikh, Irina, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, and NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Pezza, Alexandre B., Greater Wellington Regional Council, Wellington, New Zealand Phillips, C., Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, Madison, Wisconsin Phillips, David, Environment and Climate Change Canada, Toronto, Ontario, Canada Phoenix, G., Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom Pinty, Bernard, European Commission, Joint Research Centre, Ispra, Italy Pinzon, J., NASA Goddard Space Flight Center, Greenbelt, Maryland Po-Chedley, S., Lawrence Livermore National Laboratory, Livermore, California Polashenski, C., USACE, ERDC, Cold Regions Research and Engineering Laboratory, and Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire Purkey, Sarah G., Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California Quispe, Nelson, Servicio Nacional de Meteorología e Hidrología del Perú, Lima, Perú Rajeevan, Madhavan, Earth System Science Organization, Ministry of Earth Sciences, New Delhi, India Rakotoarimalala, C., Madagascar Meteorological Service, Antananarivo, Madagascar Rayner, Darren, National Oceanography Centre, Southampton, United Kingdom Raynolds, M. K., Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska Reagan, James, Earth System Science Interdisciplinary Center/ Cooperative Institute for Climate and Satellites–Maryland, University of Maryland, College Park, Maryland, and NOAA/ NESDIS National Centers for Environmental Information, Silver Spring, Maryland Reid, Phillip, Australian Bureau of Meteorology, and Antarctic Climate and Ecosystems Cooperative Research Centre, Hobart, Tasmania, Australia Reimer, Christoph, EODC, Vienna, Austria Rémy, Samuel, Institut Pierre-Simon Laplace, CNRS / UPMC, Paris, France Revadekar, Jayashree V., Indian Institute of Tropical Meteorology, Pune, India Richardson, A. D., School of Informatics, Computing and Cyber Systems and Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, Arizona Richter-Menge, Jacqueline, University of Alaska Fairbanks, Fairbanks, Alaska Ricker, R., Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany Rimmer, Alon, Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic and Limnological Research, Migdal, Israel Robinson, David A., Department of Geography, Rutgers University, Piscataway, New Jersey Rodell, Matthew, Hydrological Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, Maryland Rodriguez Camino, Ernesto, Agencia Estatal de Meteorología, Madrid, Spain Romanovsky, Vladimir E., Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska Ronchail, Josyane, Université Paris Diderot/Laboratoire L’OCEAN-IPSL, Paris, France Rosenlof, Karen H., NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Rösner, Benjamin, Laboratory for Climatology and Remote Sensing, Faculty of Geography, University of Marburg, Marburg, Germany Roth, Chris, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Roth, David Mark, NOAA/NWS Weather Prediction Center, College Park, Maryland Rusak, James A., Dorset Environmental Science Centre, Ontario Ministry of the Environment and Climate Change, Dorset, Ontario, Canada Rutishäuser, T., Swiss Academies of Arts and Science, Berne, Switzerland Sallée, Jean-Bapiste, Sorbonne Universités, L’OCEAN-IPSL, Paris, France, and British Antarctic Survey, Cambridge, United Kingdom Sánchez-Lugo, Ahira, NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Santee, Michelle L., Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California Sasgen, L., Climate Sciences Department, Alfred Wegener Institute, Bremerhaven, Germany Sawaengphokhai, P., Science Systems and Applications, Inc., Hampton, Virginia Sayad, T. A., Department of Meteorology, Al-Azhar University, Egypt Sayouri, Amal, Direction de la Météorologie Nationale Maroc, Rabat, Morocco Scambos, Ted A., National Snow and Ice Data Center, University of Colorado Boulder, Boulder, Colorado Scanlon, T., Department of Geodesy and Geoinformation, Vienna University of Technology, Vienna, Austria Schenzinger, Verena, Department of Meteorology and Geophysics, University of Vienna, Austria Schladow, S. Geoffrey, Tahoe Environmental Research Center, University of California at Davis, Davis, California Schmid, Claudia, NOAA/OAR Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida Schmid, Martin, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland Schreck III, Carl J., North Carolina State University, Cooperative Institute for Climate and Satellites-North Carolina, Asheville, North Carolina Selkirk, H. B., Universities Space Research Association, NASA Goddard Space Flight Center, Greenbelt, Maryland Send, Uwe, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California Sensoy, Serhat, Turkish State Meteorological Service, Ankara, Turkey Sharp, M., Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada Shi, Lei, NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Shiklomanov, Nikolai I., Department of Geography, George Washington University, Washington, D.C. Shimaraeva, Svetlana V., Institute of Biology, Irkutsk State University, Russia Siegel, David A., University of California–Santa Barbara, Santa Barbara, California Silow, Eugene, Institute of Biology, Irkutsk State University, Russia Sima, Fatou, Division of Meteorology, Department of Water Resources, Banjul, The Gambia Simmons, Adrian J., European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom Skirving, William J., NOAA/NESDIS Coral Reef Watch, College Park, Maryland, and ReefSense Pty Ltd, Townsville, Queensland, Australia Smeed, David A., National Oceanography Centre, Southampton, United Kingdom Smeets, C. J. P. P., Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands Smith, Adam, NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Smith, Sharon L., Geological Survey of Canada, Natural Resources Canada, Ottawa, Ontario, Canada Soden, B., Rosenstiel School of Marine and Atmospheric Science, University of Miami, Key Biscane, Miami, Florida Sofieva, Viktoria, Finnish Meteorological Institute (FMI), Helsinki, Finland Sparks, T. H., Coventry University, Coventry, United Kingdom Spence, Jacqueline M., Meteorological Service, Jamaica, Kingston, Jamaica Spillane, Sandra, Met Éireann, Irish Meteorological Service, Dublin, Ireland Srivastava, A. K., India Meteorological Department, Jaipur, India Stackhouse, Jr., Paul W., NASA Langley Research Center, Hampton, Virginia Stammerjohn, Sharon, Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, Colorado Stanitski, Diane M., NOAA/OAR Earth System Research Laboratory, Boulder, Colorado Steinbrecht, Wolfgang, German Weather Service (DWD), Hohenpeissenberg, Germany Stella, José L., Servicio Meteorológico Nacional, Buenos Aires, Argentina Stengel, M., Deutscher Wetterdienst, Offenbach, Germany Stephenson, Kimberly, Department of Physics, The University of the West Indies, Jamaica Stephenson, Tannecia S., Department of Physics, The University of West Indies, Jamaica Strahan, Susan, Universities Space Research Association, NASA Goddard Space Flight Center, Greenbelt, Maryland Streletskiy, Dimitri A., Department of Geography, George Washington University, Washington, D.C. Strong, Alan E., NOAA/NESDIS Coral Reef Watch, College Park, Maryland, and Global Science and Technology, Inc., Greenbelt, Maryland Sun-Mack, Sunny, Science Systems and Applications, Inc., Hampton, Virginia Sutton, Adrienne J., NOAA/OAR Pacific Marine Environmental Laboratory, Seattle, Washington Swart, Sebastiaan, Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden, and Department of Oceanography, University of Cape Town, Rondebosch, South Africa Sweet, William, NOAA/NOS Center for Operational Oceanographic Products and Services, Silver Spring, Maryland Takahashi, Kenneth S., Servicio Nacional de Meteorología e Hidrología del Perú, Lima, Perú Tamar, Gerard, Grenada Airports Authority, St. George’s, Grenada Taylor, Michael A., Department of Physics, The University of the West Indies, Jamaica Tedesco, M., Lamont–Doherty Earth Observatory, Columbia University, Palisades, New York, and NASA Goddard Institute of Space Studies, New York, New York Thackeray, S. J., Centre for Ecology and Hydrology, Lancaster, United Kingdom Thoman, R. L., NOAA/National Weather Service, Alaska Region, Fairbanks, Alaska Thompson, Philip, Joint Institute for Marine and Atmospheric Research, University of Hawaii, Honolulu, Hawaii Thomson, L., Department of Earth Sciences, Simon Fraser University, Burnaby, British Columbia, Canada Thorsteinsson, T., Icelandic Meteorological Office, Reykjavik, Iceland Timbal, Bertrand, Singapore Meteorological Service, Singapore Timmermans, M.-L., Yale University, New Haven, Connecticut TImofeyev, Maxim A., Institute of Biology, Irkutsk State University, Russia Tirak, Kyle V., NOAA/NESDIS Coral Reef Watch, College Park, Maryland, and Global Science and Technology, Inc., Greenbelt, Maryland Tobin, Skie, Bureau of Meteorology, Melbourne, Victoria, Australia Togawa, H., Tokyo Climate Center, Japan Meteorological Agency, Japan Tømmervik, H., Norwegian Institute for Nature Research, Tromsø, Norway Tourpali, Kleareti, Aristotle University, Thessaloniki, Greece Trachte, Katja, Laboratory for Climatology and Remote Sensing, Faculty of Geography, University of Marburg, Marburg, Germany Trewin, Blair C., Australian Bureau of Meteorology, Melbourne, Victoria, Australia Triñanes, Joaquin A., Laboratory of Systems, Technological Research Institute, Universidad de Santiago de Compostela, Santiago de Compostela, Spain, and NOAA Atlantic Oceanographic and Meteorological Laboratory, and Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida Trotman, Adrian R., Caribbean Institute for Meteorology and Hydrology, Bridgetown, Barbados Tschudi, M., Aerospace Engineering Sciences, University of Colorado, Boulder, Boulder, Colorado Tucker, C. J., NASA Goddard Space Flight Center, Greenbelt, Maryland Tye, Mari R., Capacity Center for Climate and Weather Extremes (C3WE), National Center for Atmospheric Research, Boulder, Colorado van As, D., Geological Survey of Denmark and Greenland, Copenhagen, Denmark van de Wal, R. S. W., Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands van der A, Ronald J., Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands van der Schalie, Robin, VanderSat B.V., Haarlem, Netherlands van der Schrier, Gerard, Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands van der Werf, Guido R., Faculty of Earth and Life Sciences, VU University Amsterdam, Netherlands Van Meerbeeck, Cedric J., Caribbean Institute for Meteorology and Hydrology, Bridgetown, Barbados Velden, Christopher S., Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin– Madison, Madison, Wisconsin Velicogna, I., University of California, Irvine, California Verburg, Piet, National Institute of Water and Atmospheric Research, Hamilton, New Zealand Vickers, H., Norut Northern Research Institute, Tromsø, Norway Vincent, Lucie A., Environment and Climate Change Canada, Toronto, Ontario, Canada Vömel, Holger, Earth Observing Laboratory, National Center for Atmospheric Research, Boulder, Colorado Vose, Russell S., NOAA/NESDIS National Centers for Environmental Information, Asheville, North Carolina Wagner, Wolfgang, Department of Geodesy and Geoinformation, Vienna University of Technology, Vienna, Austria Walker, D. A., Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska Walsh, J., International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska Wang, Bin, Department of Atmospheric Science and IPRC, University of Hawaii, Honolulu, Hawaii Wang, Junhong, State University of New York, Albany, New York • The chapter editors thank David Parker, John Kennedy, and Elizabeth Good for providing de-tails and comprehensive internal reviews of this chapter. The editors also thank Paul Berrisford (ECMWF), Mike Bosilovich (NASA), and Shinya Kobayashi (JMA) for timely provision of reanalysis data used herein. Robert Dunn, Kate Willett, Colin Morice, and Rob Allan were supported by the Joint UK BEIS/Defra Met Office Hadley Centre Climate Programme (GA01101). • RIW was funded by EUSTACE (EU Surface Tem-perature for All Corners of Earth) which received funding from the European Union’s Horizon 2020 Programme for Research and Innovation, under Grant Agreement no 640171. Satellite data processed under UK Natural Environment Re-search Council project Globolakes (grant reference NE/J023345/2). This work was partly supported by Russian Ministry of Education and Science (project #6.1387.2017), by the grants of Russian Science Foundation МА - 17-14-01063 and of the Lake Baikal Foundation for support of ap-plied ecological studies (https://baikalfoundation .ru/project/tochka-1/). SGS and SW funded by the Tahoe Regional Planning Agency. Lake surface water temperatures in Poland were provided by the Institute of Meteorology and Water Manage-ment in Warsaw. • SEPK is supported by ARC grant number FT170100106. • Hyungjun Kim was supported by the Japan So-ciety for the Promotion of Science KAKENHI (16H06291) for this contribution. • This research was supported by grants from NASA’s GRACE and GRACE-FO Science Team. GRACE land data processing is supported by the NASA MEaSUREs Program. • The ESA CCI SM datasets and the authors were supported by ESA’s Climate Change Initiative for Soil Moisture (Contract No. 4000104814/11/I-NB and 4000112226/14/I-NB) and the European Union’s FP7 EartH2Observe “Global Earth Obser-vation for Integrated Water Resource Assessment” project (grant agreement number 331 603608). We would also like to thank support from the Copernicus Climate Change Service implemented by ECMWF. • Historical ozone observations from the 1950s at Mauna Loa Observatory and from the 1960s at South Pole were digitized by Samuel J. Oltmans, NOAA, retired. The authors would like to ac-knowledge a NASA Upper Atmosphere Composi-tion grant for support that helps sustain the frost point hygrometer soundings at Boulder, Lauder and Hilo. Henry Selkirk and Holger Vömel would like to acknowledge support from the NASA Upper Atmosphere Composition Observations program. The CAMS interim Reanalysis has been produced by the Copernicus Atmosphere Monitoring Services (CAMS). The European Centre for Medium-Range Weather Forecast (ECMWF) runs CAMS on behalf of the European Commissions. Antje Inness and Johannes Flemming are funded by CAMS. Melanie Coldewey-Egbers, Daan Hubert, Diego Loyola, Victoria Sofieva, and Mark Weber are grateful to ESA’s Climate Change Initiative Ozone project and to the EU Copernicus Climate Change Service 312a Lot4 Ozone project for supporting the generation and extension of the GTO-ECV total ozone and SAGE-CCI-OMPS data records. Stacey M. Frith is supported by the NASA Long Term Measurement of Ozone program WBS 479717. Lucien Froidevaux’s contribution, with the assistance of Ryan Fuller, was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Daan Hubert acknowledges the partial support by the EU/ERC Horizon 2020 project GAIA-CLIM. • The GFASv1.4 dataset was provided the by GFAS-CLIM project, which is funded by the German Bundesministerium für Wirtschaft und Energie (BMWi FKZ 50EE1543), and the Copernicus CAMS_44 project. • NCAR is sponsored by the National Science Foundation. • NOAA Coral Reef Watch work is supported pri-marily by the NOAA Coral Reef Conservation Program and the NOAA National Environmental Satellite, Data, and Information Service’s Center for Satellite Applications and Research. The scien-tific results and conclusions, as well as any views or opinions expressed herein, are those of the author(s) and do not necessarily reflect the views of NOAA or the U.S. Department of Commerce. • Data from the RAPID-WATCH MOC monitoring project are funded by the Natural Environment Research Council. • MOVE contributions were made under award NA15OAR4320071 from the Climate Observa-tions Division, National Oceanic and Atmospheric Administration, U.S. Department of Commerce. Previously, MOVE was funded by the German Bundesministerium für Bildung und Forschung (Grants 03F0246A and 03F0377B). • The Florida Current cable and section data are funded by the DOC-NOAA Climate Program Of-fice - Ocean Observing and Monitoring Division. • The XBT data are funded by the NOAA Office of Climate Observations. • Argo data are collected and made freely avail-able by the International Argo Program and the national programs that contribute to it; the Argo Program is part of the Global Ocean Observing System. The editors would like extend their thanks and appreciation to Joe Pelissier, the retired Meteorologist-in-Charge of the NOAA/NWS Weather Forecast Office in Greenville-Spartanburg, SC, for his inputs regarding the passing of his good friend and colleague Charlie Neumann. Carl Schreck was supported by NOAA through the Cooperative Institute for Climate and Satellites - North Carolina under Cooperative Agreement NA14NES432003. • Martin Jeffries thanks the Office of Naval Research (Code 32) for supporting his role as Associate Editor of the State of the Climate Re-port and co-editor of the Arctic section. Jackie Richter-Menge acknowledges that this publication is the result in part of research sponsored by the Cooperative Institute for Alaska Research with funds from the National Oceanic and Atmospheric Administration under cooperative agreement NA13OAR4320056 with the University of Alaska. Emily Osborne acknowledges the NOAA Arctic Research Program for supporting her role as co-editor of the State of the Climate Report Arctic section and coauthor of the paleoclimate sidebar. • Marco Tedesco would like to acknowledge the NASA Cryosphere Program (NNX17AH04G, NNX16AH38G), the NASA IDS program (NNX14AD98G) and the Office of Polar Programs at the National Science Foundation (OPP 1643187, PLR-1603331). PROMICE stations are funded by the Danish Energy Agency. KAN stations are funded by SKB. IS acknowledges funding by the Helmholtz Climate Initiative REKLIM (Regional Climate Change), a joint research project of the Helmholtz Association of German Research Cen-tres (HGF) and the German Research Foundation through grant SA 1734/4-1. The Netherlands Polar Programme (NPP) of the NWO (Netherlands Institute for Scientific Research) is acknowledged for the K-transect support. • Vladimir Romanovsky and coauthors acknowl-edge the support of the State of Alaska, the Na-tional Science Foundation (grants PLR-0856864 and PLR-1304271 to the University of Alaska Fairbanks; PLR-1002119 and PLR-1304555 to the George Washington University), Natural Resources Canada and the Norwegian Meteorological Institute. Support was also provided by the Russian Science Foundation (project RNF 16-17-00102) and by the government of the Russian Federation. • G. Bernhard and coauthors acknowledge the U.S. National Science Foundation for supporting UV measurements at Barrow and Summit, a Research Council of Norway Centres of Excellence award (Project 223268/F50) to the Norwegian Radiation Protection Authority, and the Academy of Fin-land for supporting UV measurements through the FARPOCC, SAARA, and ILMA pilot proj-ects. We also acknowledge Tove Svendby from the Norwegian Institute for Air Research and Arne Dahlback from the University of Oslo for overseeing UV measurements at Oslo, Andøya and Ny-Ålesund, and thank Juha M. Karhu, Tomi Karppinen and Markku Ahponen from the Finnish Meteorological Institute for operating the Brewer UV spectroradiometer at Sodankylä. Valuable climate information was provided by National Meteorological and Hydrological Services (NMHSs) of the WMO RA VI Region, either by direct submission to the authors or via the web. The Editor wishes to thank all the authors for their timely contributions, and the internal and external reviewers and document editors for their thoughtful and constructive comments. The following grants (China National Key R&D Program 2017YFA0603802 and 2015CB453201, NSFC grant 41630423, NSF grant AGS-1643297) are acknowledged. Environment Monitoring Service CPC: Climate Prediction Center (NOAA) CSIRO/ACE CRC/IMAS-UTAS: (Australia) Commonwealth Scientific and Industrial Research Organisation Antarctic Climate & Ecosystems Cooperative Research Centre Institute for Marine and Antarctic Studies - University of Tasmania Deutscher Wetterdienst Essential Climate Variable European Space Agency Earth System Research Laboratory (NOAA) Fast Longwave And Shortwave Radiative Fluxes Global Ocean Ship-based Hydrographic Investigations Program Global Ocean Data Assimilation System Global Precipitation Climatology Project Gravity Recovery and Climate Experiment Instituto Nacional de Meteorologia (Brazil)