‘A Significant and Robust Cooling Trend’ In the Southern Ocean From 1982–2020 Defies Climate Models

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A new study reports there has been a -0.3°C cooling in the Southern Ocean since 1982 per multiple observational data sets. The authors detail the “failure of CMIP5 models in simulating the observed SST cooling in the Southern Ocean.”

The Southern Ocean is today about 1-2°C colder than it has been for nearly all of the last 10,000 years (Shuttleworth et al., 2021Civel-Mazens et al., 2021Ghadi et al., 2020). It is now about 4°C colder than during the Last Glacial Maximum, when CO2 levels were estimated to be 180 ppm (Civel-Mazens et al., 2021).

Image Source: Shuttleworth et al., 2021

Image Source: Civel-Mazens et al., 2021

Image Source: Ghadi et al., 2020

Image Source: Civel-Mazens et al., 2021

A new study (Xu et al., 2022) suggests the Southern Ocean (50°S–70°S) has continued to cool for the last 40 years, with amplitudes ranging from -0.1°C to -0.3°C per decade in some regions.

Climate models are unable to simulate this cooling, as they are famously incapable of accurately depicting the role of cloud forcing in modulating sea surface temperature trends.

“SST in the Southern Ocean is considered as an important indicator of climate change. This study shows that the Southern Ocean (50°S–70°S) sea surface temperature has a significant and robust cooling trend during 1982–2020”

Image Source: Xu et al., 2022

via NoTricksZone

By Kenneth Richard on 27. June 2022