Aerosols from Asia are slowing down Atlantic currents, impacting Earth climate, study finds

NEW DELHI: Aerosol emissions from Asia are slowing down currents in the Atlantic Ocean which help keep the climate of the surrounding continents temperate, according to new research.

A crucial component of the Earth's climate system, the complex system of currents in the Atlantic Ocean, the Atlantic Meridional Overturning Circulation or the AMOC, is widely being investigated to identify if it is slowing down or close to a collapse.

Likening the AMOC to the ventilation system in our homes, the study authors explained that shutting down the Atlantic system of currents was equivalent to "switching off the heater in the middle of the winter".

It is already established that aerosols and increasing greenhouse gases over North America and Europe are contributing factors for the AMOC's slowdown.

Using climate models, the international team of scientists from the Ocean University of China and the Max Planck Institute for Meteorology in Germany have shown that aerosols coming from human activities in Asia too are slowing down the Atlantic's system of currents.

"Understanding how the Asian aerosols can have an impact 12,000 miles downstream, that finding made this research novel," said Jian Lu, Earth scientist at the US Department of Energy's (DOE's) Pacific Northwest National Laboratory (PNNL), and co-author of the study published in the journal Nature Communications.

"It was something we didn't know before. The climate is full of surprises!" said Lu.

The aerosol emissions work to reduce AMOC's movements by shielding the solar heating and cooling the Earth's climate, the researchers explained.

Often referred to as a conveyor belt, this complex system of currents brings warm water north and cold water south in the Atlantic Ocean, as well as important nutrients, they said.

Lu described the AMOC like a cell that is continuously turning over its warm layer with its cold layer, thereby helping keep the climate of the surrounding continents temperate.

For the study, the team used existing data from widely used tools, like the Detection and Attribution Model Intercomparison Project (DAMIP) and the Aerosol Chemistry Model Intercomparison Project (AerChemMIP). DAMIP aims to help estimate how natural and human processes affect global warming, while AerChemMIP is designed to quantify how aerosols impact climate.

The researchers argued for reducing aerosol emissions from Asia that could help stabilise the AMOC, in addition to lowering local air pollution.