Researchers from the University of Exeter managed to gain new insight into the environmental changes that occurred on Earth during the period of regional cooling known as the Little Ice Age (LIA) that started around the 13th century and ended in mid-19th century, being most pronounced in the North Atlantic.
The authors of the new study, which was published in the journal Nature Communications last month, studied shells of hard clams – marine bivalve mollusks that can potentially live for centuries – in order to try to assess how the ocean “evolved and responded to external changes over recent centuries,” as Science Daily put it.
During the course of their research, the team determined that the “subpolar North Atlantic system experienced a two-phase destabilization” during the transition from the warm Medieval Climate Anomaly to the Little Ice Age.
“The vulnerability of the North Atlantic system to externally forced perturbations is a critical issue today, with recent analysis suggesting that this system has destabilized during the last century and might be approaching a tipping point,” the researchers wrote.
They also warned that, “if rapid loss of Arctic sea-ice, accelerating melting of the Greenland ice sheet, and associated export of freshwater into key convective regions in the North Atlantic continues, a subpolar gyre tipping point might again lead to rapid and long-lasting regional climate change.”
"Our latest analysis suggests that the system of ocean currents in the northern North Atlantic could be at risk of a tipping point again now due to global warming, leading once again to abrupt climate change over Europe," said Professor Tim Lenton, director of the University of Exeter’s Global Systems Institute and one of the authors of the study.