Scientists sound warning over global warming; melting ice in Antarctica is slowing deep-water currents in oceans

Scientists have issued another warning about global warming, stating that melting ice in and around Antarctica is threatening to severely slow deep-water currents in oceans worldwide. This could potentially impact the spread of freshwater, oxygen, and nutrients that sustain life for centuries. The researchers published their findings in the journal ‘Nature’ on Wednesday.

According to the study’s model, faster Antarctic ice melts are driving a ‘significant slowdown’ of water circulation in the ocean depths, which will slow by 40% by 2050 in a high-emissions scenario. The study warns of impacts that would last ‘for centuries to come.’ Climate professor Matthew England at the University of New South Wales (UNSW) says that if the model is correct, the deep ocean current will be ‘on a trajectory that looks headed towards collapse.’

Scientists claim that trillions of tonnes of cold, highly salty and oxygen-rich water sinks around Antarctica each year, sending a deep-water current northwards to the Indian, Pacific, and Atlantic oceans. However, greater volumes of melting ice make the Antarctic waters less dense and salty, slowing the deep-water circulation with consequences for climate, sea level, and marine ecosystems. Professor England compared the oceans to lungs, and said that if oceans become stagnant below 4000 meters, ‘this would trap nutrients in the deep ocean, reducing the nutrients available to support marine life near the ocean surface.’

While UNSW Emeritus Professor John Church, who was not involved in the study, stated that there were many uncertainties about the impact of a declining deep ocean circulation, he noted that continuing on a high greenhouse gas emission pathway would lead to even more profound effects on the ocean and climate system. He urged the world to drastically reduce emissions to get off the high-emission pathway we are currently following.

The study team included lead author Qian Li of the Massachusetts Institute of Technology and co-authors from the Australian National University and Australia’s national research organization, CSIRO.