Back in early 2003, I came across an issue of either Science or Nature that had a theory paper in it on how changing the salinity of the Atlantic could cause the amazing currents in that body of water to shut down. Right now, salty water heated in the tropics is circulated northward, and it brings the energy necessary to allow the very northern British isles to have a warm enough climate that there are palm trees. As that energy warms northern Europe, Ireland, and the UK, the water sinks down and circles back toward the tropics along the bottom of the sea. It is the salty at the surface and less salty down deep density differences that allow this circulation pattern to exist. In that magazine issue, they talked about how an influx of fresh water into the Atlantic could shut down that circulation and plunge those northern places into the cold.

And later in the journal, there was an article on how the melting of Greenland’s ice sheets was changing the Earth’s salinity. People who love me took away my general science journals for a while and told me to just look toward the stars, but twenty years later, none of us should be looking away.

New research has shown that, toward the end of the last ice age, a massive glacier lake burst and flooded the Atlantic with fresh water. This shut down the circulation pattern and plunged Europe into a thousand-year ice age. Now, data is showing that changing salinity is causing the current circulation to falter, and at any moment, the freshwater flowing off Greenland could be the final straw that ends this pattern.

More Information

A critical ocean system may be heading for collapse due to climate change, study finds (The Washington Post)

“Observation-based early-warning signals for a collapse of the Atlantic Meridional Overturning Circulation,” Niklas Boers. 2021 August 5, Nature