2020 temperature tied record

 From ClimateCrocks

Temperatures last year tied the modern record, climate scientists reported today. Overall, the planet was about 1.25°C warmer than in preindustrial times, according to jointly reported assessments from NASA, the U.K. Met Office, and other institutions.

The annual update of global surface temperatures—an average of readings from thousands of weather stations and ocean probes—shows 2020 essentially tied records set in 2016. But the years were nothing alike. Temperatures in 2016 were boosted by a strong El Niño, a weather pattern that warms the globe by blocking the rise of cold deep waters in the eastern Pacific Ocean. Last year, however, the Pacific entered La Niña, which has a cooling effect. That La Niña didn’t provide more relief is an unwelcome surprise, says Nerilie Abram, a climate scientist at Australian National University. “It makes me worried about how quickly the global warming trend is growing.”

The past 6 years are the six warmest on record, but the warming of the atmosphere is unsteady because of its chaotic nature. The ocean, which absorbs more than 90% of the heat from global warming, displays a steadier trend, and here, too, 2020 was a record year. The upper levels of the ocean contained 20 zettajoules (1021joules) more heat than in 2019, and the rise was double the typical annual increase, scientists reported yesterday in Advances in Atmospheric Sciences. The subtropical Atlantic Ocean was particularly hot, fueling a record outbreak of hurricanes, says Lijing Cheng, a climate scientist at the Chinese Academy of Sciences’s Institute of Atmospheric Physics who led the work.

This heat, monitored down to 2000 meters by a fleet of 4000 robotic probes, is spreading deeper into the ocean while also migrating toward the poles. An extreme heat wave struck the northern Pacific, killing marine life. For the first time, warm Atlantic waters were seen penetrating into the Arctic Ocean, melting sea ice from below and driving its extent nearly to a record low. The warming ocean and melting ice sheets are raising sea levels by 4.8 millimeters per year, and the rate is accelerating.

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