A massive ocean current encircling Antarctica, known as the Antarctic Circumpolar Current (ACC), is accelerating due to global warming, according to a new study.
This current plays a critical role in regulating Earth’s climate.
The Mightiest Current on Earth
The study, published in Nature, examined the past 5.3 million years of the ACC’s behavior using deep-sea sediment cores.
The researchers, led by Dr. Gisela Winckler of Columbia University, found that the ACC is the strongest and fastest current on the planet, churning a staggering 6 billion cubic feet of water per second.
Dr. Winckler suggests a link between a faster ACC and the retreat of Antarctic ice due to global warming.
A Current Driven by Wind and Shaped by Time
Fueled by westerly winds, the ACC circles Antarctica at roughly 2.5 miles per hour.
Geologists believe the conditions for this vortex emerged 34 million years ago, but it only reached its current form 12-14 million years in the past.
International Collaboration Uncovers Ancient Secrets
The research team, comprised of scientists from a dozen countries, used the JOIDES Resolution drill ship to collect sediment cores from the ocean floor near Point Nemo, the most remote spot on Earth.
These cores, ranging from 500 to 650 feet long, held clues to the ACC’s history.
Particle Sizes Reveal the Past
By analyzing the size of particles trapped in the sediment, the researchers were able to determine past current speeds.
Smaller particles settle during periods of slower current flow, while larger particles can only sink during faster ACC movement.
This analysis revealed periods of changing current speeds that matched known climate shifts on Earth.
A Link Between Current Speed and Ice Loss
The study also found a correlation between faster ACC speeds and periods of glacial ice retreat in West Antarctica.
The researchers believe this is due to increased heat transport to the south, brought by a stronger ACC.
Dr. Frank Lamy, the study’s lead author, warns that a stronger ACC could lead to more warm water reaching the edges of Antarctic ice shelves, further accelerating ice melt.
World News
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