February 2023 was Earth’s 4th-warmest February on record » Yale Climate Connections

February 2023 was Earth’s fourth-warmest February since global record-keeping began in 1850. It was 0.97 degree Celsius (1.75°F) above the 20th-century average, NOAA’s National Centers for Environmental Information reported March 14. NASA also rated February 2023 as the fourth-warmest February on record, 1.24 degrees Celsius (2.23°F) above the 1880-1920 period, which is its best estimate for when preindustrial temperatures occurred. February 2023 was the fifth-warmest February on record according to the European Copernicus Climate Change Service and fourth-warmest according to the Japan Meteorological Agency. Minor differences in the agencies’ rankings can result from the different ways they treat data-sparse regions such as the Arctic. Note that new research by NOAA has now extended the global temperature record back to 1850 (an extra 30 years); the February 2023 report is the first one that uses this new dataset. The new dataset has also improved its handling of missing data regions like the Arctic.

Land areas had their fourth-warmest February on record in 2023, with global ocean temperatures the fifth-warmest, according to NOAA. Asia had its seventh-warmest February on record; Europe, South America, and Africa each had a top-20 warmest February on record, ranking 11th (tied), 13th, and 17th (tied) warmest, respectively. Oceania and North America each had a warmer-than-average February, but it did not rank among the 30 warmest on record for those regions.

As detailed in our March 8 post, the contiguous U.S. experienced its 18^th-warmest February and 17th-warmest winter, with 20 states notching a top-10 warmest February and 26 states recording a top-10 winter. Ice cover on the Great Lakes was at near record-low levels for the winter.

La Niña ends

The three-year La Niña event that began in August 2020 has finally ended, NOAA reported in its March monthly discussion of the state of the El Niño/Southern Oscillation, or ENSO. Neutral conditions are expected to persist through the Northern Hemisphere spring, then transition to El Niño by late summer, continuing until at least the end of 2023.

NOAA’s and Columbia University’s International Research Institute for Climate and Society ENSO forecast for the peak portion of the Atlantic hurricane season (August-September-October) is for a 4% chance of La Niña, a 35% chance of ENSO-neutral, and a 61% chance of El Niño. The El Niño models are predicting higher chances than that of an El Niño event, with the dynamical model consensus favoring a borderline weak/moderate event for the peak of hurricane season. However, predicting the exact timing of any potential switch to El Niño later this year is difficult, as we are currently in the “spring predictability barrier,” when forecasts of ENSO behavior are at their toughest.

Atlantic hurricane activity and El Niño

Atlantic hurricane seasons during El Niño events tend to be quiet because of increased vertical wind shear over the Atlantic. Since 1960, there have been 18 El Niño events that fell during the August-September-October peak of the Atlantic hurricane season; only four of these seasons had average or above average Atlantic tropical cyclone activity when measured by accumulated cyclone energy: 1963, 1969, 2004, and 2018.

The most recent El Niño to occur during the peak of the Atlantic hurricane season was in 2018, when a weak El Niño event was just getting going. The developing El Niño event did not arrive in time to significantly dampen hurricane activity, however, and the season was near-average by most measures, with 15 named storms, eight hurricanes, two intense hurricanes, and an accumulated cyclone energy index of 133. The 1991 – 2020 seasonal averages were 14.4 named storms, 7.2 hurricanes, 3.2 intense hurricanes, and an Accumulated Cyclone Energy of 123. Two hurricanes that year — Florence and Michael — caused unusually high death tolls (53 and 49, respectively) and catastrophic damage in excess of $25 billion each.

The most recent strong El Niño was in 2015, which saw a below-average year for Atlantic hurricane activity: 11 named storms, four hurricanes, two intense hurricanes, and an accumulated cyclone energy  index of 60% of average. The year featured unusually high levels of wind shear over the Caribbean, making it difficult for tropical systems to organize and strengthen in those waters. However, this high wind shear did not extend as far east as usual, allowing several tropical storms to form near the coast of Africa over waters that were near-record warm. Near record-warm to record-warm ocean temperatures were also over more northern reaches of the Atlantic and helped spur the formation of Hurricane Joaquin and Hurricane Kate. Hurricane Joaquin accounted for 46% of the season’s accumulated cyclone energy.

Arctic sea ice: third-lowest February extent on record

Arctic sea ice extent during February 2023 was the third-lowest in the 44-year satellite record, according to the National Snow and Ice Data Center. However, winter ice extent is a poor indicator of what the ice extent will be in summer and fall.

Antarctic sea ice: lowest on record

Antarctic sea ice extent in February was the lowest on record. By Feb. 14, it had broken the all-time seasonal low record set on Feb. 25, 2022, and has remained below the previous all-time low the rest of the month. Low Antarctic sea ice is concerning since the ice helps buttress land-based ice shelves that can contribute to sea level rise if not stabilized. Formation of Antarctic sea ice also helps drive an important ocean current system, the overturning thermohaline circulation, as explained in a Feb. 12 article at Inside Climate News.