Arctic Ocean Starts Warmer Decades Sooner Than We Thought – Research – Getting Better With That?
UNIVERSITY OF CAMBRIDGE
CREDIT: SARA GIANSIRACUSA
The Arctic Ocean has warmed since the early 20sNS century – decades earlier than recorded – due to warmer water flowing into fragile polar ecosystems from the Atlantic Ocean.
An international team of researchers has reconstructed the recent history of ocean warming at the gateway to the Arctic Ocean in an area known as the Fram Strait, between Greenland and Svalbard.
Using chemical signatures found in marine microorganisms, the researchers found that the Arctic Ocean began to warm rapidly at the turn of the last century as warmer and saltier water flowed in from the Atlantic Ocean. Atlantic Ocean – a phenomenon called Atlantification – and this change is likely to precede the warming recorded by modern instrumental measurements. Since 1900, ocean temperatures have increased by about 2 degrees Celsius, while sea ice has receded and salinity increased.
The results, reported in the journal Scientific advance, provides the first historical perspective on the Atlantization of the Arctic Ocean and reveals a connection with the North Atlantic that is much stronger than previously thought. This connection has the potential to shape climate change in the Arctic, which could have important implications for sea ice retreat and global sea level rise as polar ice sheets continue. melt.
All of the world’s oceans are warming due to climate change, but the Arctic Ocean, the smallest and shallowest of the world’s oceans, is warming the fastest.
“The rate of Arctic warming is more than twice the global average, due to feedback mechanisms,” said co-author Dr Francesco Muschitiello from Cambridge’s Department of Geography. “Based on satellite measurements, we know that the Arctic Ocean has warmed steadily, especially over the past 20 years, but we wanted to put the recent warming into a longer context.”
Atlantis is one of the causes of Arctic warming, but instrumental records capable of tracking this process, such as satellites, go back only about 40 years.
As the Arctic Ocean warms, it causes polar ice to melt, which in turn affects global sea levels. As the ice melts, it exposes more of the sun to the ocean’s surface, releasing heat and increasing the air temperature. As the Arctic continues to warm, it will melt permafrost, which stores large amounts of methane, a greenhouse gas far more harmful than carbon dioxide.
The researchers used geochemical and ecological data from ocean sediments to reconstruct changes in water column properties over the past 800 years. They dated the sediments accurately using a combination of methods and looked for diagnostic signs of Atlantis, such as changes in temperature and salinity.
“When we look at the entire 800-year period, our temperature and salinity records look pretty stable,” said co-author Dr Tesi Tommaso from the Research Council’s Institute of Polar Sciences. Country in Bologna said. “But suddenly at the beginning of my 20sNS century, you get a marked variation in temperature and salinity – it really emerges. ”
“The reason for this rapid Atlantis at the gateway to the Arctic Ocean is fascinating,” says Muschitiello. “We compared our results with ocean circulation at lower latitudes and found a strong correlation with a slowdown in dense water formation in the Labrador Sea. In a future warming scenario, this subarctic deep circulation is expected to decrease further as the Greenland ice sheet melts. Our results imply that we can expect more Arctic Atlantis in the future due to climate change.”
The researchers say that their results also show a possible flaw in climate models, because they do not reproduce this early Atlantis process at the turn of the last century.
“Climate simulations often do not simulate this type of warming in the Arctic Ocean, meaning that there is an incomplete understanding of the mechanisms driving Atlantis,” said Tommaso. “We rely on these simulations to predict future climate change, but the lack of any indication of early warming in the Arctic Ocean is a missing piece of the puzzle.”
Francesco Muschitiello is a Fellow of Sidney Sussex College, Cambridge.
JOURNEYS
Scientific advance
DOI
RESEARCH METHODS
Observational research
RESEARCH SUBJECTS
Do not apply
ARTICLE TITLE
Rapid penetration along the Fram Strait in the early 20th century
ARTICLE PUBLICATION DATE
November 24, 2021
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