Updated climate models clouded by scientific biases, researchers find

Southern Ocean surrounds Antarctica [image credit: theozonehole.com]

Another hole in ‘settled’ climate science? Over-sensitivity to changing conditions may sound familiar. Researchers find “The major implication is that, even though the latest CMIP models improve the simulation of their mean states, such as radiation fluxes at the top of the atmosphere, the detailed cloud processes are still of large uncertainty.” Southern Ocean clouds seem to have been ‘improperly simulated’ when compared to data.
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Clouds can cool or warm the planet’s surface, a radiative effect that contributes significantly to the global energy budget and can be altered by human activities, claims Eurekalert.

The world’s southernmost ocean, aptly named the Southern Ocean and far from human pollution but subject to abundant marine gases and aerosols, is about 80% covered by clouds.

How does this body of water and relationship with clouds contribute to the world’s changing climate?

Researchers are still working to figure it out, and they’re now one step closer, thanks to an international collaboration identifying compensation errors in widely used climate model protocols known as CMIP6. They published their findings on September 20 in Advances in Atmospheric Sciences.

“Cloud and radiation biases over the Southern Ocean have been a long-lasting problem in the past generations of global climate models,” said corresponding author Yuan Wang, now an associate professor in the Department of Earth, Atmospheric, and Planetary Sciences at Purdue University. “After the latest CMIP6 models were released, we were anxious to see how they performed and whether the old problems were still there.”

CMIP6, a project of the World Climate Research Programme, allows for the systematic assessment of climate models to illuminate how they compare to each other and real-world data. In this study, Wang and the researchers analyzed five of the CMIP6 models that aim to serve as standard references.

Wang said the researchers were also motivated by other studies in the field that point to the Southern Ocean’s cloud coverage as a contributing factor to some CMIP6 models’ high sensitivity, when the simulations predict a surface temperature that rises too quickly for the rate of increased radiation.

In other words, if improperly simulated, the Southern Ocean clouds may cast a shadow of doubt on the projection of future climate change.

Full article here.