POCATELLO — A newly published paper by Idaho State University scientists details how changes to ocean currents can impact climate on the other side of the world.

The paper, published in Nature Communications, was written by Bruce Finney, professor in the departments of biological sciences and geosciences at ISU. Finney collaborated with Lesleigh Anderson, a research geologist with the United States Geological Survey, and ISU alum W. Brad Baxter.

The paper details how shifts in Atlantic Ocean currents 13,000 years ago caused Alaska’s climate to cool, particularly in winter.

Finney said the Gulf Stream flows north through the Atlantic Ocean, delivering heat to northern latitudes.

“This northward flow can be interrupted if a lot of freshwater is dumped into the North Atlantic in areas around Greenland,” Finney said. “As glaciers melted at the end of the last ice age, a lot of freshwater was discharged into this region, halting the flow of heat northward. This caused a well-known climate reversal back to glacial-like conditions that affected the North Atlantic region, including Scandinavia and Europe, for about 1,000 years.”

To investigate, the researchers analyzed sediment cores from three Alaskan lakes — April Fools Lake, Neklason Lake and Finger Lake — and compared them to ice cores from Greenland to examine what was happening simultaneously in the Atlantic and Pacific.

“The cores continuously record information about the environment as they pile up at the bottom of lakes or in snow that turns to ice in glaciers,” Finney said. “These lakes are important because they are adjacent to the North Pacific Ocean and sensitive to changes in that region which impact climate over a large part of North America.”

The researchers compared the ratio of oxygen isotopes in both sets of cores and found they decreased around the same time, suggesting Atlantic Ocean currents drove shifts in Alaska’s climate thousands of years ago.

“Because previous strong evidence for this event in this region was lacking, we did not expect to see it,” Finney said. “We determined that the climate cooling was mainly in winter, which explains why most records in Alaska hadn’t found it, as they studied things like pollen, which don’t tell us much about winter.”

Baxter said comparing the two different climate proxies offered multiple perspectives on the findings.

“From understanding what aspects of climate the lake isotopes represent, to correlating their variability with other paleorecords,” Baxter said. “It gave us multiple perspectives on the story.”

The team is now analyzing cores from other Alaskan lakes to verify their results.

“There are frequent news stories these days concerned about how changes in Atlantic Ocean currents will affect future climates,” Finney said. “The new data from Alaska gives insight into how such changes might affect the other side of the globe, including Idaho.”

Baxter said he found it easy to stay motivated throughout the project.

“I got to work with a fun, insightful, and supportive research team on some exciting datasets,” Baxter said. “Also, any chance to do fieldwork in Alaska was a major perk for me.”