Except for a few pockets of warming along the West Antarctic coast, surface air temperatures have cooled profoundly across East Antarctica – most of the continent, as well as the surrounding Southern Ocean – in the last 40 years (1979-2018). About 30% of the cooling can be explained by Madden-Julian Oscillation forcing.

Atmospheric CO2 concentrations rose from 337 ppm in 1979 to 408 ppm in 2018.

But according to graphical illustrations of surface air temperature (SAT) trends from satellite observations documented in a new study (Hsu et al., 2021), nearly the entire continent of Antarctica and much of the surrounding Southern Ocean have undergone about -0.02°C/year (-0.2°C per decade) SAT cooling during this period.

East Antarctica’s temperatures have fallen by about 1°C in the last 40 years, with approximately -0.4°C cooling from 1999-2018 relative to 1979-1998.

Per the authors, one-third of this 40-year cooling trend can be attributed to Madden-Julian Oscillation (MJO) forcing. The MJO influence is “likely to accelerate” the long-term cooling trend for East Antarctica in the coming decades.

Image Source: Hsu et al., 2021

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July 12, 2021