Yair Rosenthal, a distinguished professor in the Department of Earth and Planetary Sciences, recently co-authored a study on short-term disruptions of deep ocean circulation during warm interglacial periods. The disruptions can potentially have a serious impact on our climate, Rosenthal said.
“(The study) is a collaborative work led by my colleagues in the University of Bergen, Norway,” he said. “The work was primarily done by Eirik V. Galaasen, a (postdoctoral researcher) at the university.”
Rosenthal said he was motivated to look into the idea due to the uncertainty about the consequences that future warming of the planet will have on deep ocean circulation.
“We have worked on these issues for the past 10 years and published the first paper on disruptions of deep ocean circulation during warm intervals in Science Magazine in 2014,” he said.
Rosenthal also discussed some specifics of the study and what it could potentially mean for the future.
“This is a part of a long study looking at the possible effects of future warming on the melting of the Greenland ice sheet and the implications for the formation of deep water currents,” he said.
The study mostly took place in Norway and Greenland, Rosenthal said, while some of the analyses were done at Rutgers.
“(The work was done by) using sediment cores recovered by the International Ocean Discovery Program,” Rosenthal said. “The studied core is located on the Eirik Ridge, a sediment drift south of Greenland.”
Sediment cores are long cylinders, made of Earth’s crust, that are drilled from the seafloor, according to the Smithsonian. They tell scientists about Earth’s past geology and climate based on their layers.
The team observed warm interglacial periods from the past 450,000 years and found that they show a potential pattern of century-long disruptions of the North Atlantic Deep Water formation, according to an article by the Rutgers Institute of Earth, Ocean and Atmospheric Sciences (EOAS). It was also noted that these disruptions occurred no matter what type of global warming was present at the time.
“(The findings suggest that) instabilities of deep ocean circulation are not unique just to glacial periods, but also to warm times,” Rosenthal said.
Based on the past evidence of the disruptions and the fact that they are not specific to glacial periods, Rosenthal said similar century-long disruptions could occur in the future. The study also suggests it is climate change that is contributing to the potential slowing and stopping of deep ocean circulation in the Atlantic, according to the EOAS.
When the polar ice sheets in the Arctic melt due to climate change, this results in more freshwater in the ocean, further leading to a disruption of the circulation pattern, according to the EOAS. While the normal circulation would bring warm water up by North America and Europe, this would no longer occur after a disruption.
“Such disruption can affect the climate in the northern hemisphere, especially Europe, leading to very cold periods,” Rosenthal said.
The next step of the study includes verifying the observations from other sights near Greenland during other warm intervals, according to the EOAS.