Climate change – marine flow in danger

For many, the Antarctic is an almost mythical continent: far from everything and- at least for most of us- not really achievable and tangible. But the continent, which consists of 98 percent of ice, is of great importance for science because it has profound effects on the climate and oceans of the earth. “Enclosed in the four -kilometer layer of ice is a unique archive of the climate of our planet of the past million years,” it is not for nothing that the British Antarctic Survey.

If the currents become weaker, this could affect biodiversity and fishing.

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In the waters around this misanthropic region, the mighty Antarctic circumpolar power (ACC) is moving. The ACC is five times stronger than the Gulf Stream and part of the global “conveyor belt” of the oceans, which connects the Pacific, the Atlantic and the Indian Ocean. The system regulates the earth’s climate and pumps water, heat and nutrients around the world.

For years, researchers have repeatedly warned that fresh, cool water from the melting antarctic ice diluted the salty water of the ocean and the vital sea flow may be bothered by it. Now a team from the University of Melbourne and the Norwegian Research Center Norce shows that the current in a scenario with high carbon dioxide emissions will probably slow down by around 20 percent by 2050.

“The ocean is extremely complex and finely balanced,” said Bishakhdatta Gayen from the University of Melbourne, one of the authors of the specialist magazine »Environmental Research Letters«Published study. Breaking its previous engine together, so this could have far -reaching consequences for life on earth: the climate could fluctuate more in the future, with more extreme weather events in certain regions. In addition, global warming could progress even faster because the oceans were less able to₂ to absorb and thus look less than carbon storage.

In one Scientific essay on the topic The researchers also compare the Antarctic circumpolar power “with a ditch around the icy continent”. “The current helps to keep warm water away and thus protects sensitive ice surfaces,” write Gayen and his colleague Taimoor Sohail. However, it also acts as a barrier to invasive species and also play a major role in regulating the earth’s climate. Advances in ocean modeling and access to the largest supercomputer in Australia, the »Gadi«, Now enabled a thorough investigation of potential changes. When cold, fresh meltwater from the Antarctic moves to the north – according to the forecast – this leads to significant changes in the density structure of the ocean. If the currents become weaker, as the modeling shows, this could affect biodiversity and fishing that many coastal communities are dependent on. In addition, invasive types such as southern giant tang could penetrate the Antarctic and disturb the local ecosystems and food networks.

According to the research team, a weaker current could also lead to more warm water penetrating south, which would make melting the antarctic ice rinks worse again and thus contribute to the global increase in sea level. “A faster melting of the ice could then lead to a further weakening of the current,” explain the scientists. A true vicious circle.

The new, dark forecast for the Antarctic circumpolar power coincides with scenarios that have been designed earlier. Nevertheless, the scientists don’t want to paint apocalyptic image. The future is not predetermined, emphasize Sohail and Gayen. Common efforts to reduce greenhouse gas emissions could still limit melting around Antarctic.