Above: Map of global temperature departures from average by percentile in January 2020. Areas of record warmth included far northern Europe, western Russia, and the equatorial Atlantic, with smaller areas scattered across Asia, Australia, and North and South America. There were no areas of record cold. (NOAA/NCEI)
The 2020s are off to an ominously warm start. The planet just saw its warmest January in records going back to 1880, NOAA concluded in its monthly global climate report issued Thursday.
Feeding into this record were the warmest land temperatures and the second warmest ocean temperatures on record, according to NOAA. When averaged vertically across the lowest 8 kilometers (5 miles) of the atmosphere, global satellite-measured temperatures were the warmest or second warmest for January in the 42-year record, according to the University of Alabama Huntsville (UAH) and RSS, respectively.
The worldwide average surface temperature ended up 1.14°C (2.05°F) above the 20th-century norm, narrowly topping the 1.12°C (2.01°F) from January 2016. The warmest four Januaries in the NOAA record have all occurred since 2016.
Similar to NOAA, Europe’s Copernicus Climate Change Service placed January 2020 narrowly above January 2016. As of this writing, NASA had not released its monthly report.
What’s more impressive than the margin of warmth itself is that it occurred without any assistance from an official El Niño event. El Niño tends to produce warmer global temperatures, as the warm sea-surface temperatures slathered across the central and eastern tropical Pacific transfer ocean-stored heat into the atmosphere. In turn, the cooler-than-average waters of La Niña tend to depress global temperature. These ups and downs occur atop the steady rise from long-term warming that results mainly from fossil fuel use.
The most unusual warmth on record during a non–El Niño month
The previous January record from 2016 occurred during one of the strongest El Niño events on record. In contrast, neutral conditions were in place during January 2020, with the tropical Pacific slightly warmer than average but not enough to qualify as El Niño.
In fact, for every month of every year in NOAA's database going back to 1880, January 2020 was the warmest of them all, relative to average, when considering only those times when neutral conditions were present (neither El Niño nor La Niña). Over the long term, neutral conditions are in place almost half the time. Only three other months during neutral periods have been at least 1°C above average: March 2017 (1.08°C or 1.94°F), December 2019 (1.05°C or 1.89°F), and February 2017 (1.02°C or 1.84°F).
The YouTube animation below, created by Dana Nuccitelli, vividly illustrates the tendency of El Niño and La Niña periods to be warmer and cooler, respectively, with long-term planetary warming obvious in both cases.
Cold air was hard to come by in January
Near-record warmth encompassed almost every continent during January. An exceptionally strong positive phase of the Arctic Oscillation (which hit an all-time record in early February) kept cold air mostly bottled up far to the north, mainly across Alaska and the Arctic Ocean. It was the second warmest January on record for Asia, Europe, South America, and the Hawaiian region, and the third warmest for Australia and Oceania. It was only the 16th warmest January over North America, though, mainly because of the chill over far western Canada and Alaska; the latter saw its 13th coldest January on record.
The concentrated cold in the far north allowed Arctic sea ice to make a half-hearted stab at recovery, though it must be stressed that the long-term prognosis for Arctic ice in a warming world remains grim. The average sea ice extent in January was the eighth lowest in 42 years of recordkeeping and the largest since the early 2010s, according to the National Snow and Ice Data Center.
Record warmth played out over northern Europe in startling fashion, as summarized by Capital Weather Gang’s Matthew Cappucci. For the first time, the Scandinavian capitals outside of Iceland—Copenhagen, Helsinki, Oslo, and Stockholm—all got above freezing on every day in January, reported Mika Rantanen (Finnish Meteorological Institute). The only snowfall in any of these four cities was a mere 3 cm (1.2”) in Oslo on January 31.
Each of the 48 contiguous U.S. states was warmer than average in January, as we reported last week. Coming on the heels of a mild December, the warmth in January and early February put much of the southeast U.S. on track for trees budding out several weeks ahead of normal.
The year has kicked off with two billion-dollar weather-related disasters, according to the insurance broker Aon: the much-publicized catastrophic wildfires in Australia and a severe weather outbreak across the U.S. South on January 10-12. Among global stations with a period of record of at least 40 years, 28 set new all-time heat records in January, and 3 set all-time cold records.
For details on these and other noteworthy global climate events from last month, see the roundup from Dr. Jeff Masters at Scientific American.