State of the Climate in 2022

Throughout 2022, the “triple-dip” La Niña (three consecutive years) showed its hand in a large number of the essential climate variables and metrics that are covered in this chapter. La Niña conditions tend to have a cooling effect on global temperatures in comparison to neutral or El Niño years and impact precipitation patterns around the globe. Upper-level wind patterns at 200 hPa across the globe for 2020–22 showed a striking similarity with the last triple-dip La Niña that occurred in 1998–2000. Yet, despite the cooling effect of the ongoing La Niña, 2022 was still among the six warmest years since global records began in the mid-to-late 1880s, according to six datasets of global surface temperatures. It was also the warmest La Niña year on record, surpassing 2021. Exceptional heatwaves occurred across the globe in 2022, boosted by above-average temperatures that continue their relentless long-term rise. In Europe, the “unweather”—an Old English term for weather so severe that it appears to come from a different climate or world—shattered records across the continent during the summer months, while rivers and reservoirs fell to critically low levels. Meanwhile China experienced its hottest summer on record and at Wuhan, the Yangtze River reached record-low values. The extreme high summer temperatures over Europe resulted in unprecedented melting of glaciers in the Alps, with over 6% of their volume lost in Switzerland this year alone, a record loss. Globally, 2022 was the 35th consecutive year of glacier mass loss and the 14th consecutive year of exceptional loss (more than 500 mm water equivalent). Ice cover on lakes was almost nine days shorter than average, the fourth shortest since 1980; the five shortest ice seasons have all occurred since 2016. The average temperature anomaly for more than 1950 lakes across the Northern Hemisphere was the second highest since the beginning of the record in 1995. Drought conditions were pervasive, occurring across Europe (linked to the extreme summer temperatures), as well as the American West, China, and most of Southern Hemisphere South America. Globally, record-high areas of land experiencing extreme drought (6.2%) were reached in August 2022; overall, 29% of land experienced moderate or worse categories of drought. Low values of terrestrial water storage also occurred in Europe and parts of China (linked to the heatwaves), but La Niña influenced high values in southeastern Australia. Extreme rainfall was observed in southeastern and eastern Australia as well as in Pakistan, which received around three times its normal August monsoon rainfall. However, precipitation amounts for the globe as a whole and over the ocean was much lower than normal, but close to normal over land. Total column water vapor and surface humidity were close to normal over the ocean. Despite ‘normal’ rainfall amounts over land and lower terrestrial water storage, 2022 saw continued above-average soil moisture values, which are approaching the level of the previous global record in 2011. Lake water levels were higher than normal overall, but cloudiness was below normal. Overall, 2022 was a mixed year for the hydrological variables presented in this chapter. In addition to the ongoing La Niña, other climate modes of variability in 2022 included a negative Indian Ocean dipole, a positive winter North Atlantic Oscillation (NAO), and the second highest summer NAO on record. The Southern Annular Mode was positive for a record-equaling Brought to you by University of Colorado Libraries | Unauthenticated | Downloaded 09/23/25 10:48 PM UTC September 2023 | State of the Climate in 2022 2. Global Climate S21 76% of days in 2022; it was the sixth time 60% of days has been exceeded since 2015, compared to only 10 years between 1979 and 2014 where high positive rates of >60% of days occurred. The most significant long-term changes in atmospheric composition continue to be record levels of long-lived greenhouse gases (LLGHGs). Globally averaged carbon dioxide, methane, and nitrous oxide levels in 2022 continued to increase rapidly by 2.2 ppm, 14.4 ppb, and 1.3 ppb to 417.1 ppm, 1911.8 ppb, and 335.7 ppb, respectively. Collectively, all LLGHGs contributed 3.4 W m−2 of all radiative forcing, with the main three LLGHGs accounting for 98% of the increase in the last five years. As measured by equivalent effective stratospheric chlorine, the gases that destroy stratospheric ozone continue to decline nearly linearly. Since the 2018 discovery of post-2011 renewed trichlorofluoromethane (CFC-11) emissions, in violation of the Montreal Protocol, illegal emissions have mostly disappeared. Considering short-lived atmospheric components, global mean aerosol optical depth in 2022 was the lowest on record, as was carbon monoxide, reflecting fewer fires in 2022 on top of a long-term decreasing trend likely reflecting global improvements in fossil fuel combustion efficiency. Tropospheric ozone has continued to trend upwards with an 8% increase since 2004. The most remarkable impact on short-lived species in 2022 resulted from the Hunga Tonga–Hunga Haʻapai underwater volcanic eruption (HTHH) in January 2022, discussed in Sidebar 2.2. Stratospheric aerosols registered their largest perturbation since the Mt. Pinatubo eruption of 1991. The HTHH eruption injected ~50 Tg–150 Tg of water vapor into the stratosphere, an amount unprecedented in the satellite record which represents more than 10% of the entire stratospheric water vapor burden, an anomaly that will persist for several years. Low amounts of early summer snow cover in the Northern Hemisphere, along with increased plant growth and associated greening resulting from La Niña-induced rainfall decreased the global albedo in 2022. Carbon emissions from biomass burning during 2022 were 22% below the long-term average, making it the lowest fire year on record. However, considerable fire activity was still observed in boreal North America, parts of Europe, and central South America. This year, a new measure of humid heat events is introduced in Sidebar 2.1, using equivalent heat indices based on the wet bulb temperature rather than air temperature. Humid heat extremes have increased in both magnitude and frequency since 1973, and 2022 was above average for both. Time series and anomaly maps for 2022 from many of the variables described in this chapter can be found in Plates 1.1 (Chapter 1) and 2.1. Most sections now use the 1991–2020 climatological reference period, in line with World Meteorological Organization recommendations. This was not possible for all datasets depending on their length of record or legacy processing methods at the time of writing and is noted accordingly. Finally, already looking towards the next reports, we welcome expressions of interest from those who wish to propose new sections for this chapter or wish to bring their expertise to existing author teams.