Last year, a study suggested that one of the Earth's major ocean currents is heading toward collapse. Unfortunately, new data now supports that.
“Changes in temperature, sea level and precipitation will severely affect society Climate change is unstoppable in human time scales,” authors of a recent study I warn you in an article For conversation.
It's a terrifying prospect, and one of the most important parts of the new study is an early warning system, identified by University of Utrecht oceanographer René van Westen and colleagues.
This view of the future at least gives the world the ability to prepare for what is to come.
“We were able to develop a physically based and observable early warning signal involving salinity transport at the southern boundary of the Atlantic Ocean,” van Westen and team Explain.
Atlantic Meridional Overturning Circulation (AMOC) is a large system of ocean currents that move warm salty water northward. As this water cools on its meandering journey north, it becomes denser. As cold water sinks, water from other oceans is drawn in to fill the surfaceRedirects the circulation system back to the south.
The AMOC has been decreasing significantly since the mid-1900s.
Melting glaciers and heavy rains increase the contribution of fresh water, decrease the salinity of seawater, and salt water becomes less dense, disrupting the sinking process and weakening the whole body circulation.
Now, by modeling these ocean systems, van Westen and colleagues have found a way to detect when the AMOC 'tipping point' is near: a decrease in salinity along the southern boundary of the Atlantic.
“Once a threshold is reached, the tipping point can follow in one to four decades.” say teachers.
The AMOC has only been directly monitored since 2004, so it has not taken long to understand the full trajectory of the current slow trend. As a result, scientists try to fill their knowledge gaps using indirect indicators such as salinity levels.
Van Westen and team have not yet put all the factors together to predict precisely when the AMOC collapse will occur, but they believe the moment of cataclysm is much closer than many current simulations suggest.
The new modeling examines the freshwater-induced tipping point itself, rather than trying to predict its timing. But the obtained data suggest that the AMOC is more sensitive to changes than calculated by most climate models.
“The new study confirms past concerns that climate models are systematic Exaggerate consistency of AMOC,” said Stefan Rahmsdorff, a climatologist at the University of Potsdam who was not involved in the study. Explained to RealClimate.
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The AMOC affects much of Earth's climate, so it's one of the key components of Earth's climate system that researchers are most concerned about. A collapse of the AMOC It happens cyclically Over a million years, and based on past events, the Arctic should extend south this time, leading to a temperature drop of up to 15 °C in northwestern Europe, disrupting the tropical monsoon and further warming the Southern Hemisphere.
The chain of reactions that follow can severely affect entire ecosystems Global food security.
“The new study adds significantly to the growing concern about AMOC decline in the not-too-distant future,” Rahmsdorff said. said The Associated Press. “We ignore this at our peril.”
This study was published Scientific advances.