An international group of scientists reconstructed the recent history of ocean warming at the gateway to the Arctic Ocean in a region called the Fram Strait, between Greenland and Svalbard, and discovered that the Arctic Ocean has been warming for much longer than earlier records have actually recommended. Credit: Sara Giansiracusa
The Arctic Ocean has been getting warmer since the beginning of the 20th century– decades earlier than records recommend– due to warmer water flowing into the delicate polar environment from the Atlantic Ocean.
A global group of scientists reconstructed the recent history of ocean warming at the gateway to the Arctic Ocean in a region called the Fram Strait, between Greenland and Svalbard.
Utilizing the chemical signatures discovered in marine bacteria, the researchers found that the Arctic Ocean started warming quickly at the beginning of the last century as warmer and saltier waters flowed in from the Atlantic– a phenomenon called Atlantification– which this change most likely preceded the warming recorded by contemporary important measurements. Because 1900, the ocean temperature has increased by around 2 degrees Celsius, while sea ice has pulled back and salinity has increased.
As the Arctic Ocean gets warmer, it triggers the ice in the polar region to melt, which in turn impacts global sea levels. As the ice melts, it exposes more of the oceans surface to the sun, releasing heat and raising air temperatures. As the Arctic continues to warm, it will melt the permafrost, which stores big quantities of methane, a far more damaging greenhouse gas than carbon dioxide.
” The factor for this quick Atlantification of at the gate of the Arctic Ocean is intriguing,” said Muschitiello. “We compared our outcomes with the ocean circulation at lower latitudes and found there is a strong correlation with the downturn of thick water development in the Labrador Sea.
The results, reported in the journal Science Advances, offer the very first historical perspective on Atlantification of the Arctic Ocean and reveal a connection with the North Atlantic that is much more powerful than formerly believed. The connection can shaping Arctic climate irregularity, which could have crucial implications for sea-ice retreat and global water level rise as the polar ice sheets continue to melt.
Using the chemical signatures discovered in marine bacteria, researchers have found that the Arctic Ocean began warming rapidly at the beginning of the last century as warmer and saltier waters streamed in from the Atlantic– a phenomenon called Atlantification. Credit: Sara Giansiracusa
All of the worlds oceans are warming due to climate modification, but the Arctic Ocean, the smallest and shallowest of the worlds oceans, is warming fastest of all.
” The rate of warming in the Arctic is more than double the global average, due to feedback mechanisms,” said co-lead author Dr. Francesco Muschitiello from Cambridges Department of Geography. “Based on satellite measurements, we understand that the Arctic Ocean has been progressively warming, in particular over the previous 20 years, but we desired to put the recent warming into a longer context.”
Atlantification is among the causes of warming in the Arctic, however crucial records efficient in monitoring this procedure, such as satellites, only go back about 40 years.
As the Arctic Ocean gets warmer, it triggers the ice in the polar region to melt, which in turn affects international sea levels. As the ice melts, it exposes more of the oceans surface area to the sun, releasing heat and raising air temperature levels. As the Arctic continues to warm, it will melt the permafrost, which stores big amounts of methane, a much more harmful greenhouse gas than co2.
The scientists utilized environmental and geochemical information from ocean sediments to reconstruct the change in water column homes over the previous 800 years. They exactly dated sediments using a combination of methods and searched for diagnostic signs of Atlantification, like modification in temperature and salinity.
” When we looked at the whole 800-year timescale, our temperature level and salinity records look pretty continuous,” said co-lead author Dr. Tesi Tommaso from the Institute of Polar Sciences of the National Research Council in Bologna. “But suddenly at the start of the 20th century, you get this marked modification in temperature level and salinity– it really sticks out.”
” The factor for this rapid Atlantification of at the gate of the Arctic Ocean is interesting,” said Muschitiello. “We compared our outcomes with the ocean flow at lower latitudes and discovered there is a strong correlation with the slowdown of thick water formation in the Labrador Sea.
The researchers state that their outcomes likewise expose a possible defect in climate models, because they do not reproduce this early Atlantification at the start of the last century.
” Climate simulations usually do not replicate this kind of warming in the Arctic Ocean, meaning theres an insufficient understanding of the systems driving Atlantification,” said Tommaso. “We rely on these simulations to project future environment change, however the absence of any signs of an early warming in the Arctic Ocean is a missing piece of the puzzle.”
Recommendation: “Rapid Atlantification along the Fram Strait at the beginning of the 20th century” by Tommaso Tesi, Francesco Muschitiello, Gesine Mollenhauer, Stefano Miserocchi, Leonardo Langone, Chiara Ceccarelli, Giuliana Panieri, Jacopo Chiggiato, Alessio Nogarotto, Jens Hefter, Gianmarco Ingrosso, Federico Giglio, Patrizia Giordano and Lucilla Capotondi, 24 November 2021, Science Advances.DOI: 10.1126/ sciadv.abj2946.
Francesco Muschitiello is a Fellow of Sidney Sussex College, Cambridge.
