Oceans Cool the Climate More Than We Thought, Study Finds

'Polar oceans constitute emission hotspots during the summer,' according to a new paper published in the peer-reviewed scientific journal Science Advances. 'And including those sea-to-air fluxes in an atmospheric chemistry-climate model 'results in a net radiative effect that has far-reaching implications.'

The research was led by a team of scientists from Spain's Institute of Marine Sciences and the Blas Cabrera Institute of Physical Chemistry, according to an announcement from the UK's University of East Anglia:

Researchers have quantified for the first time the global emissions of a sulfur gas produced by marine life, revealing it cools the climate more than previously thought, especially over the Southern Ocean. The study, published in the journal Science Advances, shows that the oceans not only capture and redistribute the sun's heat, but produce gases that make particles with immediate climatic effects, for example through the brightening of clouds that reflect this heat.

It broadens the climatic impact of marine sulfur because it adds a new compound, methanethiol, that had previously gone unnoticed. Researchers only detected the gas recently, because it used to be notoriously hard to measure and earlier work focussed on warmer oceans, whereas the polar oceans are the emission hotspots...

Their findings represent a major advance on one of the most groundbreaking theories proposed 40 years ago about the role of the ocean in regulating the Earth's climate. This suggested that microscopic plankton living on the surface of the seas produce sulfur in the form of a gas, dimethyl sulphide, that once in the atmosphere, oxidizes and forms small particles called aerosols. Aerosols reflect part of the solar radiation back into space and therefore reduce the heat retained by the Earth. Their cooling effect is magnified when they become involved in making clouds, with an effect opposite to, but of the same magnitude as, that of the well-known warming greenhouse gases, such as carbon dioxide or methane. The researchers argue that this new work improves our understanding of how the climate of the planet is regulated by adding a previously overlooked component and illustrates the crucial importance of sulfur aerosols. They also highlight the magnitude of the impact of human activity on the climate and that the planet will continue to warm if no action is taken.

The article includes this quote from one of the study's lead authors (Dr. Charel Wohl from the university's Centre for Ocean and Atmospheric Sciences). 'Climate models have greatly overestimated the solar radiation actually reaching the Southern Ocean, largely because they are not capable of correctly simulating clouds. The work done here partially closes the longstanding knowledge gap between models and observations.'

And the university's announcement argues that 'With this discovery, scientists can now represent the climate more accurately in models that are used to make predictions of +1.5 degrees C or +2 degrees C warming, a huge contribution to policy making.'


Thanks to long-time Slashdot reader schwit1 for sharing the news.

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