“Global Warming Threatens Vital Atlantic Ocean Currents: Are We Headed for Another Ice Age?”
A new study suggests that global warming caused vital Atlantic Ocean currents to collapse just before the last ice age, leading to a dramatic cooling of the Nordic Seas while surrounding oceans grew warmer. The study, led by Mohamed Ezat, an associate professor and paleoceanographer at The Arctic University of Norway, warns that we could be heading towards a similar scenario as the world warms due to climate change.
The Last Interglacial period, which occurred between the previous two ice ages, serves as an analogue for the near future if greenhouse gas emissions are not reduced. Temperatures during this period reached 1.8 to 3.6 degrees Fahrenheit above preindustrial levels. The study focused on the Last Interglacial period, specifically 128,000 years ago, when enhanced melting of Arctic sea ice had a significant impact on the overturning circulation in the Nordic Seas.
The Nordic Sea currents are part of the Atlantic Meridional Overturning Circulation (AMOC), a system essential for warming the Northern Hemisphere. The AMOC functions like a giant conveyor belt, with warm waters from the Southern Hemisphere moving northward on the ocean surface before cooling and plunging to the bottom in the North Atlantic.
Melting ice in the Arctic can disrupt the AMOC by diluting surface waters in the North Atlantic, preventing them from sinking and forming deep currents. Research shows that the AMOC is already slowing down due to global warming, and there are concerns that it could collapse in the coming decades.
Climate models suggest that the AMOC could collapse before 2100, with significant uncertainties in predicting the timescales. The study analyzed sediment cores from the Norwegian Sea to reconstruct sea ice distribution, sea surface temperature, salinity, deep ocean convection, and sources of meltwater during the Last Interglacial.
The results, published in Nature Communications, indicate that Arctic meltwater blocked the formation of deep-ocean currents in the Norwegian Sea during the Last Interglacial, slowing the southward flow of the AMOC. The study highlights the potential consequences for the AMOC in the near future, as satellite observations show a drastic decline in Arctic sea ice over the past four decades.
Ezat emphasizes the importance of climate action, stating that severe weakening of the AMOC could have serious implications for high latitude regions and beyond. The study serves as a reminder of the delicate balance of our planet’s climate and the urgent need for action to address climate change.