Ocean currents play a very important role in regulating our planet’s climate. However, it was observed that some of these currents – including AMOC – were weakening. And a recent study has shown that this current is weakening much faster than previously thought.
What is AMOC?
The Atlantic meridional overturning circulation or AMOC is a vast system of ocean currents that transport warm water from the tropics north to the North Atlantic. It is part of the Earth’s ocean circulation system and plays an important role in the global climate system. In particular, you should know that the AMOC fuels the transport of heat and nutrients towards the poles, from the tropics to the northern hemisphere and across the equator. It also draws heat and carbon to the depths of the ocean.
Thus, this ocean treadmill allows the distribution of heat around the planet. The AMOC accounts for approximately 90% of the total northward ocean heat transport across the Atlantic Ocean. Currently, AMOC has become a source of concern for climate experts. The observed slowdown in the AMOC is mainly caused by global warming, and the consequences of this phenomenon include intensified floods, hurricanes and droughts, rising sea levels and the collapse of marine ecosystems.
Towards a collapse of AMOC before the end of the century
In short, the weakening of the AMOC does not bode well for the planet. Yet in a most worrying study, researchers from the University of New South Wales in Australia found that the situation could be worse than previously thought. According to the results of their research published in the journal Nature Geosciencethe weakening of the AMOC is much faster than expected and the melting of the ice is the cause. Notably, the researchers found that the AMOC is currently lower than at any time in the last 1,000 years.
And the situation risks getting worse. In fact, according to the climate model they created, if the global temperature rise compared to pre-industrial times reaches 2 degrees Celsius, the AMOC is likely to become a third lower than it was. It was 70 years ago. Note that the Earth has already warmed by 1.5 degrees Celsius since the industrial revolution, and the Arctic is warming nearly four times faster than the rest of the planet. All this heat is melting Arctic sea ice, glaciers and the Greenland ice sheet.
However, fresh water that comes from melting ice is lighter than salty sea water. This disrupts the southward ocean flow of deep, cold Atlantic waters and weakens the AMOC. Until now, this parameter has not been included in official climate models. However, taking this into account, the researchers were able to establish that the AMOC could be 30% lower by 2040, 20 years earlier than initially predicted. And based on this figure, they also predicted that the AMOC could thus collapse before 2100. As a reminder, the Atlantic Ocean has started to collapse and the consequences are already visible.
