From the Alfred Wegener Institute and the “Melting triggers sympathetic melting” department
Scientists show how warm ocean water melted glaciers during the last glacial period – a potential template for processes affecting the modern Antarctic ice sheet
The melting of glaciers on one side of the globe can trigger disintegration of glaciers on the other side of the globe, as has been presented in a recent paper by a team of AWI scientists, who investigated marine microalgae preserved in glacial deposits and subsequently used their findings to perform climate simulations. The study highlights a process with alarming consequences for modern ice sheets—continuous warming of the ocean can result in a massive loss of polar ice mass, and consequently to rapid sea level rise.
Ocean basins around the world are interconnected by large-scale current systems, and like a global conveyor belt, the currents transport water around the globe at varying depths. The resultant distribution of warm and cold water masses is critical for global climatic conditions. Scientists at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) and MARUM Center for Marine Environmental Sciences have now documented how a change in currents in one ocean basin can trigger massive and unexpected changes in a distant basin, even on the other side of the planet.
The Bremerhaven-based researchers report in the journal Nature that during the last glacial period, a massive inflow of freshwater into the polar North Atlantic set off a chain of events in the ocean and the atmosphere, which resulted intensive glacier melting in the North Pacific, thousands of kilometres away. The source of the freshwater was melting ice sheets, which covered land masses surrounding the North Atlantic during the glacial period. At the end of the chain of events, warm water penetrated the Pacific coastal area of the North American continent, which was also covered by an ice sheet. As a result, parts of the sheet disintegrated and were released into the Pacific as large-scale flotilla of icebergs. Considering that the modern ocean is warming continuously as a result of global warming, this finding is alarming for the AWI scientists. Comparable to the process observed in the eastern North Pacific during the last glacial melting, the ongoing ocean warming may disintegrate Antarctic ice, which subsequently would result in a significant sea level rise.
Together with a team of scientists, AWI geoscientist Edith Maier describes a complex stepwise process. First indications were gathered from sediment sampling during an expedition with the German research ship Sonne 600 kilometres off the coast of Alaska. The recovered glacial sediment layers of up to cobble-sized stones, which originated in the distant continental land. The only feasible explanation: the stones must have been transported while incorporated within icebergs into the open North Pacific Ocean when the North American coast was covered by an ice sheet. Confirmation came from the dating of the layers, which reveals that the stony layers were deposited around 16,000 and 38,500 years ago, during the last glacial period. “Accordingly, we assume there were two major melting events in the North Pacific realm,” says Edith Maier.
To test this thesis, the team employed an innovative analytical technique pioneered at the AWI. The method uses diatoms to determine how intensively the salinity of ocean surface waters has declined, e.g., due to meltwater deposition. By performing an oxygen isotope analysis on the remains of the siliceous parts of diatoms preserved in the sediment record, the researchers were able to identify at what times the surface salinity was most intensively affected by melting ice. “In fact, our analyses showed that there were major inflows of freshwater into the area south of Alaska roughly 16,000 and 38,500 years ago,” confirms Edith Maier.
Previous reconstructions of glacial conditions have documented that meltwater inflows have caused major drops in surface salinity in the North Atlantic, a feature that inspired Edith Maier to investigate whether the meltwater events in the North Atlantic and the North Pacific were linked via the global water circulation. Today, warm surface water is transported from the Pacific to the Indian Ocean, then flows around the southern tip of Africa towards the Caribbean realm and then spreads into the North Atlantic via the Gulf Stream.
The driver of this global flow is the generation of cold and salty water in the polar North Atlantic. This water, produced during ice formation, is denser than warm water and therefore sinks into the deep ocean. As a result, the surface warm water is pumped to the North. But 16,000 and 38,500 years ago, the global “pumping system” was seriously disrupted by the decreased salinity of the North Atlantic. Consequently, only little warm water flowed out of the Pacific, causing the tropical Pacific to get warmer. In turn, more warm water reached the western coasts of Canada and Alaska. The inflow of warmer water destabilized the ice sheet covering the coastal areas which resulted in a discharge of the continental ice into the ocean and a drop in surface salinity.
To validate this scenario, Edith Maier asked the AWI’s climate modelers, led by Gerrit Lohmann, whether such a complex, global chain of events could be simulated using computer models. The results were unequivocal: If the oxygen isotopes are taken into account, the models clearly show that the phenomenon occurs. The model results also show that meltwater pulses in the Atlantic caused the changes in the Pacific—and not the other way round. “Our findings are also relevant for the future, because they highlight that climate effects on one side of the Earth can significantly impact regions on the opposite side,” says Edith Maier. “The AWI is currently exploring how similar phenomena involving the inflow of warmer water are now affecting the stability of the Antarctic ice sheet. There is increasing evidence suggesting that further ocean warming will jeopardise both the stability and volume of the Antarctic ice.”
The study: E. Maier et al, North Pacific freshwater events linked to changes in glacial ocean circulation, Nature (2018). DOI: 10.1038/s41586-018-0276-y
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Changes in the MOC (deep ocean currents) driving global temperature is essentially the theory put forth by Dr. William Gray a decade ago. I believe his view is this caused the recent warming from the depths of the LIA.
These changes can also be driven by changes in rainfall patterns depositing the less dense fresh water. See Thirumalai et al 2018.
Glad to see climate science is catching up to Dr. Gray’s ideas.
I believe Dr. Gray was talking about this 25-30 years ago. Of course he suffered a lot of ridicule and alienation from the scientific community for not towing the AGW line and doing some actual science. May he rest in peace!
I have long suspected that the late 20th Century warming was entirely due to the energy released when Frodo destroyed the one ring in Middle Earth. I didn’t have much evidence until I discovered a rather impressive food stain on page 302 of my first edition copy of The Return of the King.
Analysis of the diatoms in the food stain showed them to be aligned with the hypothetical location of Mount Doom. Carbon dating the ketchup revealed, through a brand new process I devised, that late 20th Century warming began when Mount Doom erupted.
While this evidence is nearly irrefutably, I was not satisfied. In order to be absolutely certain about reality, I asked some computer geeks if they could create a working model of my theory. There model worked perfectly, confirming my theory!
The real surprising result happened when they let the model run one year into the future. Basically, if I am not made King of New Zealand by December, the Nine will ride again!
There is always sniffing glue if that doesn’t work out.
My original idea for responding to this nonsense from the Alfred Wegener Institute, was to drag out the tried and true Mark Twain Quote: ““There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.” While the quote is perfectly applicable, it lacked the bite and sarcasm this article deserved. I thought it might be fun to try some creative writing, while using the same logic and reasoning as the esteemed members of the AWI. Only the subjects and pronouns were changed to highlight the absurdity of their argument.
It was difficult to create something even more absurd than the original argument. Afterall, it actually says: “To validate this scenario, Edith Maier asked the AWI’s climate modelers, led by Gerrit Lohmann, whether such a complex, global chain of events could be simulated using computer models. ” This notion that ‘if a computer model can model my theory, than my theory is valid’ is not only nonsense, it is extremely dangerous! Such notions will inevitably lead to disastrous practices and policies. In fact, it already has!
Computer models are fictional stories that try to adhere to the known laws of physics (just like great science fiction writers like Larry Niven and Arthur C. Clarke). Still much of the story is unknown, and filled in with assumptions. In climate change, there are the assumptions that climate sensitivity to increasing CO2 is large and that there is a positive water vapor feedback to this sensitivity. These two assumptions make up about 80% of the theory, and remain ‘non-factual’ to this day. The ever-growing evidence is indicating that both of these assumptions are quite wrong, and that the AGW theory is a bunch of crap, yet computer models with these assumptions, if appropriately tortured with even more assumptions, can project results that seem to fit, roughly, what has been observed. As John Von Neumann is credited with saying 65 years ago: “With four parameters I can fit an elephant, with five I can make him wiggle his trunk.” Basically, you can make a computer model do almost anything you want it to. It proves nothing!
My “One-Ring” explanation for recent warming is clearly ridiculous, but my logic and reasoning is not much worse than what is coming out of the Alfred Wegener Institute these days.
Clearly the most reasonable explanation put forward yet. Having verified the facts with sound analytical measurements makes these facts irrefutable.
Outstanding, and well done.
Good luck with that ruling New Zealand thing.
Keep a sharp lookout for the Entwives. Word has it that they were headed for southern lands before they got separated from the Ents and became lost. The Ents would be most grateful.
I have tried every way I know to post a link to graphs and the graphs themselves. All to make a point that it overlooked by apparently everybody. So the best I can do is give a disscription of them for you to find them.
The first graph has at the bottom Eath’s global temperature history showing the Global Glacial Periods and Interglacial Periods. Below the graph is the timeline by my a. To the left border of the graph is the CO2 level in ppm. In the graph are color coded Paleozoic, Mesozoic and Cenozoic with the corresponding Precambrian on the left to the Tertiary bars on the right. And on the right of the colored graph in the bottom right corner is the Average Global Temperature that at the bottom is 12 C and the top is 22 C with the Average Mean of 17 C. Many sites have used this graph to talk about how CO2 doesn’t follow temperature. So it shouldn’t be hard to find.
The key point is the Average Global Temperature of 17 C (63 F) And that 12 C (54 F) low and the high of 22 C (72 F). So keep that in mind…
The next graph is also very common. It has the Global Temperatures from about 11,700 years ago into the “Last Ice Age” – those quotation marks are intentional – as all graphs going back to that time they have 15 C (56.7 – 57 F) as the Global Mean and the graph has the temperature changes from the Holocene Climate Optimum, Roman Climate Optimum, Medieval Warming and Little Ice Age followed by the Modern Warm Period. The temperature scale on the left has the Last Ice Age about 10.5 C and the hottest is 17 C (63 F).
This is actually saying that since the “End of the Last Ice Age” Earth only warmed to a high of about 16.2 C and the cold average is 13 C. BUT, in this time frame Earth has not even reached the Global Mean of 17 C during the hottest time 6,300 years ago. With this period 15 C average we are still in an Ice Age and it never ended. Earth would have to warm another 6 degrees F just to reach the 63 F Mean of the past nearly 5 billion years. And it would have to warm another 5 C to reach a true Interglacial Period.
We are currently in a stalled 10,000 years transition from 12 C to 22 C that is just +/- 1 C variations from a cold 15 C that’s closer to the 12 C average of Global Glacial Periods.
https://wgms.ch/downloads/wgi_1988_small.pdf
“Table Al summarizes the compiled information on glacierized surface areas of the world. The large ice sheets of Antarctica (85.7%) and Greenland (10.9%) together represent 96.6% of the total area. Within 2 the remaining 3.4% (roughly 550,000 km ), slightly less than two thirds (about 2.1%) concern smaller ice caps at higher latitudes and only about 1.3% mountain glaciers (Shumskii et al. 1964). Such mountain glaciers, however, are those features of perennial surface ice most closely related to human activities at lower latitudes. Excluding the large ice sheets, 50.3% of the surface area of smaller ice caps and mountain glaciers are found in North America [mainly Canada (36.6%) and USA/Alaska (13.7%)], 43.6% in Eurasia [mainly USSR (14.1%), China (10.3%), Pakistan/India (7.3%) and Svalbard (6.7%) ], 4.7% in South America [mainly Tierra del Fuego/Patagonian Icefields (3.9%)], 1.4% in New Zealand/Subantarctic Islands and 0.002% in Africa.”
“…only about 1.3% mountain glaciers…”
Seems to 1.3% don’t have the Hp to do squat.
“The glacierized surface area of all the land ice outside the large ice sheets is in the same order of magnitude as the error in estimating the surface area of Antarctica.”
http://www.grid.unep.ch/glaciers/pdfs/glaciers.pdf
“Glaciers, ice caps and continental ice sheets cover some ten per cent of the earth’s land surface at the present time, whereas during the ice ages, they covered about three times this amount (Paterson 1994, Benn and Evans 1998). The present ice cover corresponds to about three-quarter of the world’s total freshwater resources (Reinwarth and Stäblein 1972). If all land ice melted away, the sea level would rise by almost 65 m, with the ice sheets of Antarctica and Greenland contributing about 57 and 7 metres, respectively,
and all other glaciers and ice caps roughly half a metre to this rise (IPCC 2007).”
Wow, an ENTIRE half meter!!!!
“Edith Maier asked the AWI’s climate modelers whether such a complex, global chain of events could be simulated using computer models. The results were unequivocal… the models clearly show that the phenomenon occurs.”
Sure… but this is more mathematically elegant: Von Neumann’s elephant with 5 complex parameters. His trunk really wiggles!
Mixed with new models and innovative techniques = GIGO; i.e. Garbage in, Garbage out. Mixing garbage with models does not fix their problems.
Looking at the Ventusky maps of world weather, one that tells something of the story of the Antarctic is at It contours https://www.ventusky.com/?p=-2;-63;1&l=freezing
It contours the height above sea level that freezing occurs in the atmosphere, it is an almost vertical wall running through Southern Argentina and Chile and very close to S Africa and Australia, going from sea level to 16,000 feet over a very short distance. Obviously it is winter there now and it will be interesting to see what it looks like in summer.
“Considering that the modern ocean is warming continuously as a result of global warming,…” Is that data from ARGO?
The results from chaotically-confused climate models — as in “using computer models. The results were unequivocal:”. Nothing from climate models, or any other numerical model that includes non-linear equations run iteratively, is “unequivocal”. Initial conditions used in each run produce massively different results — see the 40 Earths paper:
“40 Earths: NCAR’s Large Ensemble reveals staggering climate variability” @ur momisugly
http://www2.ucar.edu/atmosnews/perspective/123108/40-earths-ncars-large-ensemble-reveals-staggering-climate-variability
or my essay on it “Lorenz Validated” @ur momisugly https://judithcurry.com/2016/10/05/lorenz-validated/
Oh yea of little mind’s.
“Riddle me this Batman.”
Nearly 5 Billion year’s of Earths existence and scientists have studied different thing’s in less than a few hundred years, to show Earth has had Glacial Periods of averaging 12 degrees C of which there have been 5 of them. They also found that Interglacial Periods that average 22 degrees C. Of which there were 4 of those between those the 5 Glacial Periods. Each of those events lasted millions of years. But because they happened so long ago, modern science cannot accurately give fluctuations of degrees occurring during those long periods of low or high temperatures. Nor can they determine temperature fluctuations that occurred during the transitioning between those cold to Hot or those hot to Cold periods that also took about a million years, But to put them in a graph form look like strait up or down lines.
The Mean (averaged) temperature between those Glacial 12 degrees (54 degrees F) and Interglacial 22 degrees C (72 degrees F) Periods is 17 degrees C (63 degrees F) Today our Average Mean Temperature is just 15 degrees C (57 degrees F).
With all this talking about Global Warming and Climate Change. Earth has not been Warming since it stalled from Warming some 10 thousand years ago at 15 degrees C (57 degrees F) +/- only 1 degrees C (1.8 degree F). That Earths Global Temperature has only fluctuated +/- 1 degree C over a 10,000 year period, that is only 5 degrees C warmer than the peak Cold of 12 degrees C of “The Last Ice Age” and that 15 degrees Mean for those 10,000 years has still not reached Earths 17 degrees Mean. Earth is still technically part of the “Last Ice Age” and would have to get hotter by another 1.2 degree C from our current Global Temperature to even touch the 17 degrees Mean.
So here we are arguing about Global Warming and we are still in an Ice Age that has in reality stalled from Warming. People are verbally killing each other over less than 1 degree C. When we haven’t even reached the 17 degrees C Mean of Earths Temperature fluctuations. Actual Global Warming doesn’t even begin until that 17 degrees Celsius is surpassed and climbs towards 22 degrees Celsius.
The questions we should all be asking is… Why has Earths Global Temperature Stalled for the last 10,000 year’s? Why are we still in an Ice Age? What would Earth look like if it really got hotter above 17 degrees Celsius? And What would Earth look like if the Global Temperature dropped back to the 12 degrees Celsius Mean?
Scientists have screwed up with this ideology that Earth is Warming or Cooling by +/- 1 degrees Celsius, because it has Stalled for 10,000 years. Science is living in a fraction of a time frame. They only look at what’s inside this pixal and not the bigger picture. We see the Sun as it Warms and Cools with the cycles we observe. Thinking that it can’t get any hotter or colder. We worry over semantics we know so little about. All because this or that scientists find a new shinny thing to talk about, that’s killing some species somewhere because of Climate Change. While throughout the history of Earth mass extinctions have happened and then new species are thriving. Every field of science is Politicised. As the population swings from one side to another when their side is in power. Creating new swings in the debates of science that effect our Climate. But not addressing the facts that actually matter.
If this 10,000 year Stall of Global Temperatures plunged to another “Little Ice Age” or further to a colder climate. All of life on Earth will be effected. Just as if the Global Temperature increased above the 17 degrees Celsius it would cause a massive effect on all life as we know it.
But what are we doing about it? Bickering about a few fractions of a degrees Fahrenheit. That will cause all of Earths Glaciers to flood some 20% of all coastal landmass of countries globally. Area’s that had evidence of being under water in the last Interglacial Period. But the ignorance of the population and their governments allowed building in those lowland places for thousands of years. Not thinking that some day it could happen again. And the other side of that is the “Last Ice Age” – we’re still in – could just as easily reclaim those Northern areas with Glaciers that the population and Governments allowed building in those areas. Governments only see this Global Warming side as massive landmass losses and economic desasters – that effect their profits – from those heavily populated and highly profitable areas. So they make their policies to make people think they can stop Global Warming and Climate Change. And the ignorance of the population think they can control it by reducing their Carbon Footprints. Because their Government said it will. Indoctrination is how Governments control thei populations. That for over 30 year’s of indoctrination, the population thinks it can stop Earth from changing…
Terrifying pictures?
https://www.smh.com.au/environment/climate-change/greenland-villagers-evacuated-after-iceberg-comes-to-town-20180715-p4zrkn.html