Global Climate

Dunn, Robert J. H.; Aldred, Freya; Gobron, Nadine; Miller, John B.; Willett, Kate M.; Ades, Melanie; Adler, Robert; Allan, R. P.; Anderson, John; Anneville, Orlane; Aono, Yasuyuki; Argüez, Anthony; Arosio, Carlo; Augustine, John A.; Azorin-Molina, Cesar; Barichivich, Jonathan; Basu, Aman; Beck, Hylke E.; Bellouin, Nicolas; Benedetti, Angela; Blagrave, Kevin; Blenkinsop, Stephen; Bock, Olivier; Bodin, Xavier; Bosilovich, Michael G.; Boucher, Olivier; Bove, Gerald; Buechler, Dennis; Buehler, Stefan A.; Carrea, Laura; Chang, Kai-Lan; Christiansen, Hanne H.; Christy, John R.; Chung, Eui-Seok; Ciasto, Laura M.; Coldewey-Egbers, Melanie; Cooper, Owen R.; Cornes, Richard C. ORCID: https://orcid.org/0000-0002-7688-4485; Covey, Curt; Cropper, Thomas ORCID: https://orcid.org/0000-0002-3696-7905; Crotwell, Molly; Cusicanqui, Diego; Davis, Sean M.; de Jeu, Richard A. M.; Degenstein, Doug; Delaloye, Reynald; Donat, Markus G.; Dorigo, Wouter A.; Durre, Imke; Dutton, Geoff S.; Duveiller, Gregory; Elkins, James W.; Estilow, Thomas W.; Fedaeff, Nava; Fereday, David; Fioletov, Vitali E.; Flemming, Johannes; Foster, Michael J.; Frith, Stacey M.; Froidevaux, Lucien; Füllekrug, Martin; Garforth, Judith; Garg, Jay; Gentry, Matthew; Goodman, Steven; Gou, Qiqi; Granin, Nikolay; Guglielmin, Mauro; Hahn, Sebastian; Haimberger, Leopold; Hall, Brad D.; Harris, Ian; Hemming, Debbie L.; Hirschi, Martin; Ho, Shu-pen (Ben); Holzworth, Robert; Hrbáček, Filip; Hubert, Daan; Hulsman, Petra; Hurst, Dale F.; Inness, Antje; Isaksen, Ketil; John, Viju O.; Jones, Philip D.; Junod, Robert; Kääb, Andreas; Kaiser, Johannes W.; Kaufmann, Viktor; Kellerer-Pirklbauer, Andreas; Kent, Elizabeth C. ORCID: https://orcid.org/0000-0002-6209-4247; Kidd, Richard; Kim, Hyungiun; Kipling, Zak; Koppa, Akash; L’Abée-Lund, Jan Henning; Lan, Xin; Lantz, Kathleen O.; Lavers, David; Loeb, Norman G.; Loyola, Diego; Madelon, Remi; Malmquist, Hilmar J.; Marszelewski, Wlodzimierz; Mayer, Michael; McCabe, Matthew F.; McVicar, Tim R.; Mears, Carl A.; Menzel, Annette; Merchant, Christopher J.; Miralles, Diego G.; Montzka, Stephen A.; Morice, Colin; Mösinger, Leander; Mühle, Jens; Nicolas, Julien P.; Noetzli, Jeannette; Nõges, Tiina; Noll, Ben; O’Keefe, John; Osborn, Tim J.; Park, Taejin; Pellet, Cecile; Pelto, Maury S.; Perkins-Kirkpatrick, Sarah E.; Phillips, Coda; Po-Chedley, Stephen; Polvani, Lorenzo; Preimesberger, Wolfgang; Price, Colin; Pulkkanen, Merja; Rains, Dominik G.; Randel, William J.; Rémy, Samuel; Ricciardulli, Lucrezia; Richardson, Andrew D.; Robinson, David A.; Rodell, Matthew; Rodríguez-Fernández, Nemesio J.; Rosenlof, Karen H.; Roth, Chris; Rozanov, Alexei; Rutishäuser, This; Sánchez-Lugo, Ahira; Sawaengphokhai, Parnchai; Schenzinger, Verena; Schlegel, Robert W.; Schneider, Udo; Sharma, Sapna; Shi, Lei; Simmons, Adrian J.; Siso, Carolina; Smith, Sharon L.; Soden, Brian J.; Sofieva, Viktoria; Sparks, Tim H.; Stackhouse, Paul W.; Stauffer, Ryan; Steinbrecht, Wolfgang; Steiner, Andrea K.; Stewart, Kenton; Stradiotti, Pietro; Streletskiy, Dimitri A.; Telg, Hagen; Thackeray, Stephen J.; Thibert, Emmanuel; Todt, Michael; Tokuda, Daisuke; Tourpali, Kleareti; Tye, Mari R.; van der A, Ronald; van der Schalie, Robin; van der Schrier, Gerard; van der Vliet, Mendy; van der Werf, Guido R.; van Vliet, Arnold.; Vernier, Jean-Paul; Vimont, Isaac J.; Virts, Katrina; Vivero, Sebastiàn; Vömel, Holger; Vose, Russell S.; Wang, Ray H. J.; Weber, Markus; Wiese, David; Wild, Jeanette D.; Williams, Earle; Wong, Takmeng; Woolway, R. I.; Yin, Xungang; Yuan, Ye; Zhao, Lin; Zhou, Xinjia; Ziemke, Jerry R.; Ziese, Markus; Zotta, Ruxandra M.. 2022 Global Climate. Bulletin of the American Meteorological Society, 103 (8). S11-S142. https://doi.org/10.1175/BAMS-D-22-0092.1

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Abstract/Summary

In 2021, both social and economic activities began to return towards the levels preceding the COVID-19 pandemic for some parts of the globe, with others still experiencing restrictions. Meanwhile, the climate has continued to respond to the ongoing increase in greenhouse gases and resulting warming. La Niña, a phenomenon which tends to depress global temperatures while changing rainfall patterns in many regions, prevailed for all but two months of the year. Despite this, 2021 was one of the six-warmest years on record as measured by global mean surface temperature with an anomaly of between +0.21° and +0.28°C above the 1991–2020 climatology. Lake surface temperatures were their highest on record during 2021. The number of warm days over land also reached a new record high. Exceptional heat waves struck the Pacific Coast of North America, leading to a new Canadian maximum temperature of 49.6°C at Lytton, British Columbia, on 29 June, breaking the previous national record by over 4°C. In Death Valley, California, the peak temperature reached 54.4°C on 9 July, equaling the temperature measured in 2020, and the highest temperature recorded anywhere on the globe since at least the 1930s. Over the Mediterranean, a provisional new European record of 48.8°C was set in Sicily on 11 August. In the atmosphere, the annual mean tropospheric temperature was among the 10 highest on record, while the stratosphere continued to cool. While La Niña was present except for June and July, likely influencing Australia’s coolest year since 2012 and wettest since 2016, other modes of variability played important roles. A negative Indian Ocean dipole event became established during July, associated with a warmer east and cooler west Indian Ocean. Northern Hemisphere winters were affected by a negative phase of the North Atlantic Oscillation at both the beginning and end of 2021. In the Southern Hemisphere, a very strong positive Southern Annular Mode (also known as the Antarctic Oscillation) contributed to New Zealand’s record warm year and to very cold temperatures over Antarctica. Land surface winds continued a slow reversal from the multi-decadal stilling, and over the ocean wind speeds were at their highest in almost a decade. La Niña conditions had a clear influence on the regional patterns of many hydrological variables. Surface specific humidity and total column water vapor over land and ocean were higher than average in almost all datasets. Relative humidity over land reached record or near-record low saturation depending on the dataset, but with mixed signals over the ocean. Satellite measurements showed that 2021 was the third cloudiest in the 19-year record. The story for precipitation was mixed, with just below-average mean precipitation falling over land and below-average mean precipitation falling over the ocean, while extreme precipitation was generally more frequent, but less intense, than average. Differences between means and extremes can be due to several factors, including using different indices, observing periods, climatological base reference periods, and levels of spatial completeness. The sharp increase in global drought area that began in mid-2019 continued in 2021, reaching a peak in August with 32% of global land area experiencing moderate or worse drought, and declining slightly thereafter. Arctic permafrost temperatures continued to rise, reaching record values at many sites, and the thickness of the layer which seasonally thaws and freezes also increased over 2020 values in a number of regions. It was the 34th-consecutive year of mass balance loss for alpine glaciers in mountainous regions, with glaciers on average 25 m thinner than in the late 1970s. And the duration of lake ice in the Northern Hemisphere was the fourth lowest in situ record dating back to 1991. The atmospheric concentrations of the major long-lived greenhouse gases, CO2, CH4, and N2O, all reached levels not seen in at least the last million years and grew at near-record rates in 2021. La Niña conditions did not appear to have any appreciable impact on their growth rates. The growth rate for CH4, of 17 ppb yr−1, was similar to that for 2020 and set yet another record, although the causes for this post-2019 acceleration are unknown presently. Overall, CO2 growth continues to dominate the increase in global radiative forcing, which increased from 3.19 to 3.23 W m−2 (watts per square meter) during the year. In 2021, stratospheric ozone did not exhibit large negative anomalies, especially near the poles, unlike 2020, where large ozone depletions appeared, mainly from dynamical effects. The positive impact of reductions in emissions of ozone depleting substances can be seen most clearly in the upper stratosphere, where such dynamical effects are less pronounced. It was the fourth-lowest fire year since global records began in 2003, though extreme regional fire activity was again seen in North America and also in Siberia; as in 2020, the effects of wildfires in these two regions led to locally large regional positive anomalies in tropospheric aerosol and carbon monoxide abundance. Vegetation is responding to the higher global mean temperatures, with the satellite-derived measures for the Northern Hemisphere for 2021 rated among the earliest starts of the growing season and the latest end of the season on record. The first bloom date for cherry trees in Kyoto, Japan, broke a 600-year record set in 1409. This year we welcome a sidebar on the global distribution of lightning, which has been recently declared an essential climate variable (ECV) by the Global Climate Observing System (GCOS). Time series and anomaly maps from many of the variables described in this chapter can be found in Plates 1.1 and 2.1. As with other chapters, many of the sections have moved from the previous 1981–2010 to the new 1991–2020 climatological reference period, in line with WMO recommendations (see Chapter 1). This is not possible for all datasets, as it is dependent on their length of record or legacy processing methods. While anomalies from the new climatology period are not so easily comparable with previous editions of this report, they more clearly highlight deviations from more recent conditions.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1175/BAMS-D-22-0092.1
ISSN:	0003-0007
Date made live:	21 Sep 2022 14:24 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/533249

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