Working on the other side of the world, researchers have been trying to recreate the circulation patterns in the North Atlantic, looking to see how and how fast these currents may have changed over time. Specifically, they are looking at the currents responsible for carrying warm water from the tropics up along the coast of Europe and the U.K. and moderating their winters. 

The historical strength of these currents is reflected in seafloor samples that show what size grains were getting moved and allow the compositions to be measured and traced back. They find that major ice-melting events weakened these currents. While these events were triggered by warming climate melting glaciers, they also had the effect of cooling northern latitudes and triggering colder winters. This feedback led to wild oscillations in climate, currents, and glaciers over time. 

This is a reminder that when we talk about climate change, we are looking at the average of what’s happening across our entire planet. That 0.5-degree change the planet sees may be a 10-degree increase in one place and an 11-degree decrease in another. As the glaciers melt and the oceans become less salty, ironically, northern Europe and the U.K. can expect much colder winters while the American southwest and other regions have hotter summers, and those of us in the middle latitudes just see more extremes. The world, it is a-changing.

More Information

Eos article

“The North Atlantic Glacial Eastern Boundary Current as a Key Driver for Ice-Sheet—AMOC Interactions and Climate Instability,” Samuel Toucanne et al., 2021 March 7, Paleoceanography and Paleoclimatology