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Melting Arctic sea ice could affect global ocean circulation, research warns

Melting sea ice can cause temperatures to drop. Credit: Karine Nigar Aarskog / UiT Norwegian Arctic University

A warming climate in the polar regions could significantly disrupt ocean circulation patterns, a new study shows. Scientists have discovered that in the distant past, melting Arctic sea ice may have increased the flow of freshwater into the Nordic Seas, significantly impacting ocean circulation and causing temperatures to plummet across northern Europe. did.

“Our finding that accelerated melting of Arctic sea ice is likely to have caused significant cooling in northern Europe in Earth’s past is alarming,” says the study, available open access in Nature Communications said Mohamed Ezzat of the iC3 Polar Research Hub, lead author of the study.

“This is a reminder that Earth’s climate is a delicate balance that can easily be disrupted by changes in temperature and ice sheets.”

Ice-free summer conditions are expected to occur in the Arctic Ocean after 2050.

Earlier this month, dozens of climate scientists warned in an open letter that climate change is creating “a serious risk of catastrophic and irreversible impacts of major changes in ocean circulation in the Atlantic Ocean.”

The Nordic Sea, located between Greenland and Norway, is an important region for ocean heat transport, influencing weather patterns far beyond its geographical boundaries.

At the beginning of the last interglacial period, more than 100,000 years ago, global temperatures were higher than today, ice cover was reduced, and sea levels were significantly higher.

Mohammed Ezzat and his team have now linked climate warming and accelerated melting of Arctic sea ice during that era to changes in regional sea surface temperatures and ocean circulation.

As sea ice melted, the water’s salinity and density changed, disrupting normal ocean currents and altering circulation patterns and heat distribution across the ocean.

It’s important to understand the dynamics of the last interglacial, he explains. Past warm periods in Earth’s history highlight the importance of feedback mechanisms in the climate system. As the Arctic warms and sea ice decreases, further changes in ocean currents and weather patterns may occur.

Ezzat’s research team utilized a combination of biological, inorganic and organic geochemical tracers from sediment cores taken from the Nordic Seas. These cores act like time capsules, storing information about past ocean conditions. By analyzing chemical signatures within these sediments, the team was able to reconstruct past sea surface temperatures and salinity levels, freshwater input sources and deep ocean formation processes.

Mohamed Ezzat warns that many questions remain unanswered. “We can learn a lot from the open question of the last interglacial cooling in the Norwegian Sea and potentially responsible processes,” he says. “We hope our study will serve as a benchmark for climate modelers to use this period to better constrain the effects of ice change on regional and global climate.”

In this study, we use a multi-proxy approach (diatoms, bicysts, planktonic foraminiferal assemblages, sea ice biomarkers, planktonic foraminiferal Na/Ca and Ba/Ca, benthic foraminiferal assemblages) were used. Changes in ocean convection, freshwater input and water sources during the last interglacial period.

More information: Arctic freshwater outflow suppressed Nordic ocean overturning and ocean heat transport during the last interglacial, Nature Communications (2024). DOI: 10.1038/s41467-024-53401-3. www.nature.com/articles/s41467-024-53401-3

Provided by: UiT Norwegian Arctic University

Citation: Melting Arctic sea ice could affect global ocean circulation, study warns (October 27, 2024) https://phys.org/news/2024-10-arctic-sea Retrieved October 27, 2024 from -ice-affect-global. html

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