One of the great ocean currents accelerates: warming increases thaw

The Dutch scientist Paul Crutzen, winner of the Nobel Prize in chemistry in 1995, was the first to say that we live in another era, that of the Anthropocene. The human being and his influence on the planet They have created a whole new geological epoch. The climate change that humans are causing is not giving up and its effects have been felt for years. This is what all the indicators used by the international scientific community point it out.

The Antarctic Circumpolar Current (CCA), the only ocean current that circumnavigates the planet, has accelerated. This is how he collects it a new investigation published in Nature Climate Change by researchers from the Scripps Institution of Oceanography at UC San Diego, Woods Hole Oceanographic Institution, the Chinese Academy of Sciences, and UC Riverside.

These scientists have been studying its fluctuations for decades and, for the first time, the results found are cause for alarm: Global warming is not only influencing the increase in the temperature of the oceans and the normal speed of the enormous mass of water that represents the Antarctic Circumpolar Current, but both factors are also favoring the melting of Antarctica.

To understand what this historic acceleration in the CEC means, you must first know its function: this current surrounds Antarctica and separates the cold water in the south from the warmer subtropical water just in the north. It is precisely this warmer part of the Southern Ocean that absorbs much of the heat that human activities are adding to Earth’s atmosphere.

For this reason, scientists consider it vital to understand its dynamics, since what happens there couldto influence the weather elsewhere.

In recent years, the prevailing westerly winds have accelerated as the weather has warmed. The models designed by these scientists show that that acceleration of the wind does not change the ocean currents much. Rather, it energizes ocean eddies, which are circular movements of water running against main currents.

As Jia-Rui Shi, a postdoctoral researcher at Woods Hole Oceanographic Institution, assures from observations and models, the change in ocean temperature is causing “the significant acceleration of the ocean current detected during the last decades “.

“This acceleration of the CEC, especially in the Subantarctic Front, facilitates the exchange of properties, such as heat or carbon, between the ocean basins and creates the opportunity for these properties to increase in the subtropical regions of the subsoil,” says Shi.

The ocean’s warming pattern is important. When the gradient, or the amount of heat difference, between warm and cold waters increases, the currents between these two masses accelerate. “The CCA is driven primarily by the wind, but we have shown that the changes in its velocity are surprisingly mostly due to changes in the heat gradient,” says co-author Lynne Talley, a physical oceanographer at the Scripps Institution of Oceanography.

To do this, the researchers used satellite measurements of the height of the sea surface and data collected by the global network of ocean floats called Argo. The goal was spot a trend at the speed of the upper layer of the Southern Ocean that had been hidden from scientists until now.

Long-term data capture changes in the Southern Ocean were difficult to achieve before the availability of satellite-mounted instruments and the Argo network, the authors of this new research tell us. That network of autonomous floats, which measure ocean conditions Like temperature and salinity, it started in 1999 and reached its maximum capacity in 2007.

However, a complement of 4,000 more floats across the world’s oceans continue to collect data to this day. In this way, the researchers were able to use more than a decade of complete data of Argo to distinguish the trend of the accelerated current from the natural variability.

The results obtained in this research are not only concerned by the increasing trend in the speed of the CCA. Co-authors of the study assured that they also the speed of the current is likely to increase further as the Southern Ocean continues to absorb heat from human-induced global warming. The balance of the entire planet, once again, falters again.

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