By P Gosselin on 29. December 2021
In a recent paper, scientists expressed their surprise that the Arctic had started warming already back in the early 20th century, 100 years ago. This, along with the obligatory CO2 climate warming lip service, is described in a Cambridge University press release.
Hat-tip: Die kalte Sonne
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An international group of researchers 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 found that the Arctic Ocean has been warming for much longer than earlier records have suggested.
Natural oceanic currents
The Arctic Ocean has been getting warmer since the beginning of the 20th century—decades earlier than records suggest—due to warmer water flowing into the delicate polar ecosystem from the Atlantic Ocean.
An international group of researchers 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.
Atlantic waters flow into the Arctic
Using the chemical signatures found in marine microorganisms, the researchers found that the Arctic Ocean began warming rapidly at the beginning of the last century as warmer and saltier waters flowed in from the Atlantic—a phenomenon called Atlantification—and that this change likely preceeded the warming documented by modern instrumental measurements. Since 1900, the ocean temperature has risen by approximately 2 degrees Celsius, while sea ice has retreated and salinity has increased.
The results, reported in the journal Science Advances, provide the first historical perspective on Atlantification of the Arctic Ocean and reveal a connection with the North Atlantic that is much stronger than previously thought. The connection is capable of shaping Arctic climate variability, which could have important implications for sea-ice retreat and global sea level rise as the polar ice sheets continue to melt.
Atlantification is one of the causes of warming in the Arctic, however instrumental records capable of monitoring this process, such as satellites, only go back about 40 years.
Using the chemical signatures found in marine microorganisms, researchers have found that the Arctic Ocean began warming rapidly at the beginning of the last century as warmer and saltier waters flowed in from the Atlantic – a phenomenon called Atlantification.
The researchers used geochemical and ecological data from ocean sediments to reconstruct the change in water column properties over the past 800 years. They precisely dated sediments using a combination of methods and looked for diagnostic signs of Atlantification, like change in temperature and salinity.
“When we looked at the whole 800-year timescale, our temperature and salinity records look pretty constant,” said co-lead author Dr. Tesi Tommaso from the Institute of Polar Sciences of the National Research Council in Bologna. “But all of a sudden at the start of the 20th century, you get this marked change in temperature and salinity—it really sticks out.”
“The reason for this rapid Atlantification of at the gate of the Arctic Ocean is intriguing,” said Muschitiello. “We compared our results with the ocean circulation at lower latitudes and found there is a strong correlation with the slowdown of dense water formation in the Labrador Sea. In a future warming scenario, the deep circulation in this subpolar region is expected to further decrease because of the thawing of the Greenland ice sheet. Our results imply that we might expect further Arctic Atlantification in the future because of climate change.”
The researchers say that their results also expose a possible flaw in climate models, because they do not reproduce this early Atlantification at the beginning of the last century.
“Climate simulations generally do not reproduce this kind of warming in the Arctic Ocean, meaning there’s an incomplete understanding of the mechanisms driving Atlantification,” said Tommaso. “We rely on these simulations to project future climate change, but the lack of any signs of an early warming in the Arctic Ocean is a missing piece of the puzzle.”
Arno Arrak published this paper of the “Atlantification” transition at the turn of the 19th to 20th century, which directed warm water into the Arctic and initiated a century of Arctic warming.
https://journals.sagepub.com/doi/abs/10.1260/0958-305X.22.8.1069
This may now be coming to an end.
What!!!??? A flaw in a model – say it isn’t so…
From the article: “Since 1900, the ocean temperature has risen by approximately 2 degrees Celsius, while sea ice has retreated and salinity has increased.”
This would correspond with the air temperatures, too, since the U.S. unmodified, regional chart shows a 2.0C warming from 1910 to 1940.
This paper by Tesi et al is an Italian one based in Bologna, with individual authors also from Cambridge U.K., Norway and Germany. (It’s not a “Cambridge” study).
It’s incredibly interesting and important, showing a sharp transition to “Atlantification” at the turn of the 19th-20th century. It’s worth looking at the paper itself – not just the press release – and look at the figures.
https://www.science.org/doi/10.1126/sciadv.abj2946
A lot of oceanographic parameters are shown. Some start changing earlier, well back in the 18-19th centuries. Other parameters abruptly change at the start of the 20th century. A classic picture of transition in a complex system – the driving parameters and the responsive, state-flipping parameters.
It’s curious that during the whole 19th century, water temperature in the North Atlantic was higher at the depth of the LIA (little ice age). This might be surprising to some but shows that climate is ocean-adiabatic. The ocean’s colossal heat content cannot change that quickly, so a temperature change at one place means an opposite one somewhere else. Those who would expect a climate phenomenon like the LIA to show up in radiation balance changes at the top of atmosphere (TOA) would look there in vain. The heat never left the ocean.
Phil,
Do I misunderstand your comment or are you claiming that there was an early industrial warm period somewhere else on earth concurrent with the LIA being a North Atlantic-focused regional anomaly? In other words, if I grasped what you were saying, ocean currents temporarily shunted less tropical heat into the North Atlantic, so that the heat must have warmed some area that had previously been cooler?
Given that the east coast of North America was equally frigid as the British isles and Europe, where do you say that heat went?
Rich
No, the heat redistribution was vertical, not horizontal. It means that heat was withheld from the atmosphere by the ocean during the LIA, over at least the whole northern hemisphere. This caused the colder climate of the LIA. That heat was retained in the ocean. It’s well known for instance that during extensive glaciation, sea water temperature under the ice is higher than in the absence of glaciation.
So it means a kind of zero sum game regarding the huge heat content of the whole ocean.
How does the ocean do that? Isn’t the warmest part of the ocean at and very near the air interface?
Yes and that doesn’t have to change. There is a steep temperature gradient from top to bottom, from up to 30 C at the surface to near freezing at the 4km deep ocean floor. Just a subtle change in that gradient can move a lot of heat down or up.
The AMO and hence also the Arctic actually turned cooler 1902-1923:
https://www.woodfortrees.org/graph/esrl-amo/from:1880/to:1930
So you are suggesting there are no lags involved in the relationship?
Maybe a couple of weeks.
Really? Sea ice in the Arctic Ocean is the highest it’s been in nine years,
increasing more than 30% from last year, while the Antarctic’s level is
well above normal. Most years the Arctic loses ice, but this year ice extent has increased” more than 77,000 square miles. That’s according to the Ocean and Sea Ice Satellite Application Facility’s High Latitude Processing Center.
Underwater cities off the coast of Israel are under 45 meters of water and are at least 8000 years old. The ocean has been rising for ages. Anyone know what the CO2 level was 8000 years ago ?
The 40,000 miles of oceanic rift spread a bit faster as well as the warmer magma transferring heat through the Continental Crust until it reaches the point where it descends downwards. The mega floods of the Pacific Scab lands seem to happen on a 60,000 year timeline.