OCEAN HEAT CONTENT AT RECORD LEVELS IN 2021 - NOAA
Earth’s average surface temperatures continued to trend higher in 2021 with the global ocean heat content posting yet another record high, according to analysts this week.
The global surface temperature for 2021 was the sixth highest since record keeping began in 1880, according to NOAA scientists. Separately, NASA has 2021 tying with 2018 as the sixth-warmest year on record.
For 2021, the average temperature across global land and ocean surfaces was 1.51°F (0.84°C) above the 20th-century average and the sixth highest in the 1880-2021 record, NOAA reported.
Global ocean heat content, which addresses the amount of heat stored in the 0-2000 meters depth of the ocean, was a record high in 2021, surpassing the previous record set in 2020. The seven highest OHC have all occurred in the last seven years (2015-2021).
Michael Mann, the director of the Earth System Science Center at Pennsylvania State University, expects ocean warming to continue with “just about every year to be a record breaker, until we bring our carbon emissions way down and the heating stops”.
The data show unambiguous ocean warming since the late 1980s, with an eight-fold increase in the rate of warming since 1986, compared to the period between 1958 and 1985. Each decade since 1958 has been warmer than the preceding decades, Forbes.com reported Mann saying.
”The observations do pretty clearly show a more prominent and steady increase in heat content beginning in the 1970s when the cooling effect of sulfate pollutants began to tail off, and greenhouse warming began to dominate,” he says.
As the top layers of the ocean take up more and more heat, the warming reaches increasingly deeper zones.
“The top 500 meters [of the ocean] has clearly been warming since 1980,” says Kevin Trenberth, a climate scientist at the National Center for Atmospheric Research in Boulder, Colorado, who now lives in New Zealand, told Forbes.com.
“The 500-1000-meter layer [has been warming] since about 1987, 1000 to 1500 meters depth after 1998, and 1500 to 2000 meters after 2005.”
Trenberth said most people consider higher temperatures at Earth’s surface an indicator of change, but warming in the upper levels of the oceans is a better measure of the accumulation of additional heat on the planet.
NOAA said more than 90% of global warming heat accumulates in the ocean because of its large heat capacity and the other heating is manifested in warming the atmosphere, warming and drying land, and melting land and sea ice.
there are no reasonable alternatives to why this happens aside from the human emissions of heat trapping gases, NOAA said, citing IPCC reports.
