(ORDO NEWS) — The current of the West Winds, or the Antarctic Circumpolar Current, is superior in power to all others on the planet.
It is closely related to the mixing of the Southern Ocean, as well as other huge flows of water masses that are of key importance for the World Ocean and the Earth‘s climate.
All the oceans on Earth communicate with each other and are united by a network of large currents – the so-called ocean conveyor.
This conveyor, or thermohaline circulation, exists due to differences in water density, which in turn depends on its temperature and salinity.
That is why in some places huge streams of water either come to the surface, or again sink to a great depth of the ocean.
Of particular importance is the course of the West Winds, or the Antarctic Circumpolar Current (literally “around the pole”).
It is indeed associated with strong winds blowing from the west, and especially powerful between the 40th and 60th parallels of the Southern Hemisphere – these are the “roaring forties” and “furious fifties”.
No other current on the planet carries so much water and does not pass through all the meridians.
In addition, these streams sink especially deep, replenishing the circumpolar bottom waters, which account for most of the volume of the Southern Ocean.
They spread slowly from west to east at a great depth not far from the current of the Western winds.
Let’s not forget that global circulation and ocean mixing is not only carrying water. They also redistribute heat, dissolved carbon, oxygen and nutrients necessary for living beings around the planet.
Therefore, the “ocean conveyor” greatly affects the climate, ecosystems of the seas and the state of the biosphere as a whole.
Now about 250 trillion tons of water sink into the sea depths in the waters around Antarctica every year . It is rich in oxygen, saturated with salts and has a relatively low temperature.
Further, these masses of water spread to the north, delivering oxygen to the depths of the Pacific, Indian and Atlantic oceans.
The authors of a new publication in Nature , oceanologists from Australia and the USA are interested in the current and future of circumpolar bottom waters.
Among them is Professor Matthew England, who compares this huge system of currents to the lungs of the Earth.
Scientists have performed very serious computer calculations to predict changes in the circulation of water around the South Pole of the planet.
The forecast is based on the high carbon IPCC scenario and covers the period up to 2050.
It is valuable that the study takes into account some important factors that were previously neglected, such as meltwater flows flowing from the Antarctic glaciers.
It is they, and not the winds and other factors taken into account, according to the authors, that are of decisive importance in this matter.
“Our simulations have shown that if carbon emissions continue at current rates, the mixing around Antarctica will slow down by 40 percent over the next 30 years – and it looks like this current is on the way to collapse,” Professor England explained.
The main currents in the World Ocean formed long ago and have changed relatively little over the past few thousand years.
So the slowdown in the rate of mixing of water in Antarctica in the near future may be unprecedentedly fast.
If the predictions turn out to be correct (not all scientists agree with them), the water at the bottom of the Southern Ocean will stop exchanging oxygen and nutrients with the surface.
In this case, the substances necessary for the inhabitants of the World Ocean will be locked up off the coast of the icy continent.
Moreover, shutting down Antarctic waters from the global ocean pipeline could also accelerate ocean temperature rise.
The heating of the deep parts of the ocean has already been recorded using direct measurements.
The authors fear that the consequences of changes in circulation in the Southern Ocean may become global in nature and persist for centuries.
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