From CARDIFF UNIVERSITY and the “motion from the ocean makes or breaks English vineyards” department.
Ocean floor mud reveals secrets of past European climate
Samples of sediment taken from the ocean floor of the North Atlantic Ocean have given researchers an unprecedented insight into the reasons why Europe’s climate has changed over the past 3000 years.
From the warmer climates of Roman times when vineyards flourished in England and Wales to the colder conditions that led to crop failure, famine and pandemics in early medieval times, Europe’s climate has varied over the past three millennia.
For the first time, researchers have been able to pinpoint why this occurs, and the answer lies far out at sea in the North Atlantic Ocean.
Scientists from Cardiff University have studied fossil remains of shell-bearing plankton and grains buried in sediments from the North Atlantic to determine what conditions were like in the ocean on timescales of 10-20 years over a 3000-year period.
Writing in the journal Nature Communications, the researchers found that during cold periods, icy-cold waters from the Arctic would flow south into the Labrador Sea in the North Atlantic, altering the ocean circulation patterns and potentially slowing down the currents that transport heat to Europe.
“Seawater can hold more heat than the air, so it can act like a large storage heater. As such, the oceans can store and transport vast amounts of heat and are hence key for modulating our climate. Interestingly, we find changes in the circulation and distribution of waters in the North Atlantic which would have impacted the transport of heat to Europe,” explains Dr Paola Moffa-Sanchez, from Cardiff University’s School of Earth and Ocean Sciences who led the study.
Using the data contained in tiny marine fossil plankton shells and sediment grains, the researchers were able to build a record of past ocean conditions and link this with key historical records where the European climate was known to have been, on average, colder or warmer.
For example, the researchers were able to link a slowing down of the North Atlantic currents with a notorious cold period, often called the Little Ice Age, which ensconced Europe between 1300 to about 1850. Extensive cold winters were depicted in European paintings at the time, such as the famous ice skaters on the Thames in London.
Similarly, the researchers identified another slowing down of the North Atlantic currents at the same time as an extreme cold period in the 6th century, which led to widespread crop failures and famines worldwide. It is also believed that the consequences of this cold period perhaps contributed to the spreading of the Plague of Justinian — one of the deadliest pandemics in human history that took the lives of an estimated 25 to 50 million people across the world.
“Our study shows the importance of the ocean on our climate and how this has naturally varied in the past when ocean measurements were not available. We’ve been able to link our results to historical records and provide an explanation behind some of the significant effects that the climate has had on the European population,” explains Professor Ian Hall.
“Recently, because of our human influenced warmer climate, the Atlantic is receiving more freshwater from melting Arctic ice, which is in turn affecting the movement of the waters in the North Atlantic. Future changes in ocean circulation are likely to be felt within the pattern of climate change in Europe.”
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The paper: https://www.nature.com/articles/s41467-017-01884-8 (open access)
North Atlantic variability and its links to European climate over the last 3000 years
Abstract
The subpolar North Atlantic is a key location for the Earth’s climate system. In the Labrador Sea, intense winter air–sea heat exchange drives the formation of deep waters and the surface circulation of warm waters around the subpolar gyre. This process therefore has the ability to modulate the oceanic northward heat transport. Recent studies reveal decadal variability in the formation of Labrador Sea Water. Yet, crucially, its longer-term history and links with European climate remain limited. Here we present new decadally resolved marine proxy reconstructions, which suggest weakened Labrador Sea Water formation and gyre strength with similar timing to the centennial cold periods recorded in terrestrial climate archives and historical records over the last 3000 years. These new data support that subpolar North Atlantic circulation changes, likely forced by increased southward flow of Arctic waters, contributed to modulating the climate of Europe with important societal impacts as revealed in European history.
Data availability
The data sets generated during the current study are available through the NOAA climate data centre (https://www.ncdc.noaa.gov/paleo/study/22790) and available from the corresponding author.
It is good to see more articles on this. The evidence is already quite solid, as it has been since 2001 when Gerard Bond published his famous series. More data will help refine and give more detail to the picture.
Last 2000 year climate variability is mostly from solar origin. The oceanic effect Sanchez-Moffat et al., find is secondary. Low solar activity causes predominant North Atlantic Oscillation negative conditions, and those drive a change in zonal wind patterns that alters oceanic current patterns. They are just looking at the last piece of the process that reduces mostly winter temperatures in the Northern Hemisphere. The changes affect North America, Europe and North Asia (through the Siberian High), not just the Atlantic. A general cooling of the world follows. LIA was made worse by the coincidence of the lows of several solar cycles and the 1500 year oceanic cycle plus severe volcanic activity at times. An awful coincidence.
Luckily we are still far away from a return of those negative conditions.
For those that believe a return to cold conditions is imminent, just look at the spacing of those periods. We probably have a few centuries of good warm climate ahead.
And negative North Atlantic Oscillation conditions drive warm North Atlantic (AMO) phase, like since 1995.
Yes, it seems so. However the Pacific responds differently. SST there follows solar activity.
I think you’ll find that the northern north Pacific has warmed since 1995 like the AMO.
Surface winds in the Greenland region shifted around last May. That was one of the primary clues that led me to predict in late May that the Greenland SMB decline would end early, as it did in mid August. The main change was that surface winds from the south were blocked from moving into the North Atlantic as they had been doing for the last 3 years prior. I watch and save daily screenshots.
The pattern varies a bit, but the net effect is that winds in the North Atlantic are still mainly moving southward. …https://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-49.03,71.14,672/loc=-40.160,70.041
I think that this has something to do with the intent of the above story.
[“Greenland SMB” = ?? .mod]
Interesting. I think shifting wind patterns are very important for climate, but they rarely get mentioned, even less than clouds.
Thank you for the link. It is almost hypnotic.
@ur momisugly the mod…surface mass balance, sorry. I tend to automatically abbreviate it, and there was no need for Caps.
ivankinsman
Immediately following by:
“Listen to this story and more features from New York and other magazines:” (my emphasis).
I can’t believe anyone would be stupid enough to post this fantasy as evidence of anything.
“Drivers of ocean variability off SE Greenland
The comparison of our new SST record with a reconstruction of past changes in total solar irradiance (TSI) (Fig. 3a,b) indicates that episodes of warmer SSTs occurred during periods of low solar activity. It is particularly striking that SST maxima are largely concurrent with the well-known Wolf, Spörer, Maunder and Dalton solar minima of the LIA.”
https://www.nature.com/articles/s41598-017-13246-x/figures/2
Only in the East North Atlantic and Nordic seas. The solar minimum reduces the contribution of the Subpolar gyre due to the change in wind patterns. The North Atlantic current then has a higher contribution from the Tropical gyre and becomes warmer. The warmer current and colder atmosphere increase winter snow precipitation and glacier advances over Northern Europe. Winters are significantly colder, summers not so much.
Northern European winters are mostly dependent on the NAO.
Now that’s what I can climate science.
Not sure what I’m supposed to do. They didn’t mention the overturn, the thermohaline, the…ummm… Oh! The overturn! That’s it!
Still not sure what I’m supposed to do, other than perhaps be a tiny bit relieved that these people acknowledged that the Earth’s climate has a high variability and varies all the time at its own discretion.
Does this mean they are becoming willing to admit that The They have no control over climate change?
I’m still confused about what I’m supposed to do. Should I head to the grocery store again?
Off licence or liquor store
Now will the Irish and Brits look at the AMO? tick tick tick
Steven Mosher
Actually, you can have a 40000 weather stations, all data summarized like I did, and still come up with wrong answer =
From my limited sample of 54 weather stations balanced to latitude I concluded there is no man made global warming
there is no room for it in my equation?
I am supposing you still believe there is man made global warming?
let me know, just so I am up to date.
S.Mosher,
sorry, wrong picture with my story…
[although the reasoning is still correct: no global warming here where I live]
here is the correct picture
Why stop in 2014?
The clue is in the paper title; “firn” – nothing nefarious going on. It is because the snow has not compressed yet on the glacier and sealed in gas bubbles.
https://en.wikipedia.org/wiki/Firn
Are we to understand that “up to date”, for you, means 2014?
The clue is in the paper title; “firn” – nothing nefarious going on. It is because the snow has not compressed yet on the glacier and sealed in gas bubbles.
https://en.wikipedia.org/wiki/Firn
“
Umm.. where does the article mention anything about Viticulture?
Apologies. I have found it now.
And i have been taught that climate depends more than 50% on CO2, as 97% in climat change says.
Never too late to learn new things.
What this study suggests.
That during the LIA the cooling was clearly not confined to europe, but also happening over NE America which lead to a increase in cold air flowing across the Atlantic. Also it suggests that it was a increase in blocking over northern europe rather then Greenland blocking that was leading to the colder winters in europe.
‘…..an extreme cold period in the 6th century, which led to widespread crop failures and famines worldwide.’
I blame Justinian, or perhaps it had more to do with a 1470 year climate cycle.
Uh oh, are we there yet?
Steven Mosher November 27, 2017 at 8:28 am says “Now, the same skeptics who think that 40000 temperature stations is not enough to determine the global temperture…”
There is no global temperature. Temperature is local; extremely local. Raise a thermometer 1 foot or one meter and you’ll likely get a different temperature measurement.
Suppose you have 1 gram of water at 0 C, and one liter of water at 30 C.
What is the average temperature? It’s 15 C (0+30)/2
Add the 1 gram of water at 0 C to kilogram of water at 30 C; what now is the temperature?
29.97 C.
Averaging temperatures is almost meaningless except as an index where the things being measured never change and the method of measurement never changes. Then you get an index that might mean something.
Still, radiation is dependent upon temperature, not heat. So temperature is important. It’s just not global.
Here are some studies worldwide:
http://www.co2science.org/data/mwp/mwpp.php
And here is Mangini:
http://www.uni-heidelberg.de/presse/ruca/ruca07-3/klima.html
“All in all, the results of stalagmite research and its comparison with supraregional phenomena show a high variability of the climate in the last 10 000 years with abrupt changes and significant consequences for humans. The causes of these natural climatic fluctuations are still largely unexplained. The fact that many studies show a clear correlation of the climate with the carbon isotope 14C (it is influenced by the solar activity) indicates a solar drive of the climate. However, the mechanism is currently too poorly understood to be included in model calculations. The only certainty is that since 1860, the Earth’s temperature has risen by 0.7 degrees Celsius. And the fact is that burning fossil fuels will result in a further increase in atmospheric carbon dioxide. In a hundred years, this value is likely to exceed 650 ppm, which is almost twice the current level (370 ppm). Carbon dioxide is a greenhouse gas, and if it increases in the atmosphere, the Earth’s temperature will increase. How the increase in carbon dioxide levels since 1860 has contributed to the current warming is just as uncertain as warming in the future.”
Rahmstorf answers to Mangini:
http://www.pik-potsdam.de/~stefan/mangini_replik.html
Although everything is in German, but can be easily translated with a translation program for household use, which would probably go beyond the scope of a post.
Only so far: Rahmstorf does not attack Manginis work and study, but refers to the general teaching of AGW due to CO2 and the resulting warming in the future. In the context of the past climate variations cheap.
Mangini has not researched in recent years, he was outgrowed from his research field by the ubiquitous climate police.
“Recently, because of our human influenced warmer climate, the Atlantic is receiving more freshwater from melting Arctic ice, which is in turn affecting the movement of the waters in the North Atlantic. Future changes in ocean circulation are likely to be felt within the pattern of climate change in Europe.”
I thought the Arctic sea ice has not changed much in the last 10 + years
Are these folks behind the times?
Is this human influenced warmer climate proven by science or just that the Arctic sea ice extent was based on 1979 during a period of much greater sea ice when the scientists like Stephen Schneider were talking about stopping the dangerous cooling.
How quickly history is forgotten (or covered up) when there are government subsidies are at stake.
https://youtu.be/aA-6JbGbs3s
That graph should say MASIE trend, peak to peak.
Who drew that !! 😉
Thanks, good point which I missed
Okay, so what I’ve learned so far is this:
1 – the sun’s output in a solar minimum does not drop below a specific level, but the length of the solar minimum may vary from weeks to centuries.
2 – What may turn the far North and far South into ice boxes will bring rain, fertile crop land revival, and make ski resorts even wealthier, while flooding can be prevented by replanting trees that were cut down to provide pasturage. (I already knew that last bit.)
3 – There’s a previously unknown deep cold water current discovered a few years ago off the coast of Iceland, which may have something to do with the Atlantic conveyor.
4 – Last year, some of those scientists observed that the Atlantic deepwater overturn or conveyor belt was slowing. https://news.mongabay.com/2016/05/scientists-concerned-slowing-atlantic-conveyor-warn-abrupt-climate-change/
If it is, the Gulf Stream (keeps UK/western Europe sort of warmish) may see heavier winters.
5 – I should stock up on popcorn, soup fixin’s, ice cream and bird food. Oh, yeah – suet cakes, too, because those little feather flockers love those. That, and woodpecker treats so that the yellow-bellied woodpecker (beautiful feather pattern) and the downy mated pair can get some sustenance, too. I have pictures of them from last year and the previous winters when Spring was late in coming.
Could someone please let me know if Spring will be late next year? I may not have enough salt to last into April. Wanna see my snow microclimate pictures from April this year? 🙂 I may give them the squash seeds left from Thanksgiving.
Anthony, I do appreciate all the trouble you go to, to keep us informed.
I suspect that they may have the causation reversed. I suspect that the temperature is the cause of the change in the currents rather than the other way around …
Regards to all,
w.
A warming or cooling in ocean currents changes salinity, so temperature being the cause and change in current, the effect would be very likely.
There is no coincidence that every time the planet reaches a peak warmth it cools soon after. Warming of the ocean currents lowers salinity, which in turn slows them causing future cold periods because less energy is being transferred in polar regions. Eventually the currents become colder leading to higher salinity, which in turn quickens them causing a reversal to warm periods.
Herbert Lamb displayed a chart in one of his books which showed the Gulf Stream, during the LIA, veering east sooner than during warm periods such as the MWP.
“…researchers were able to link a slowing down of the North Atlantic currents with a notorious cold period…”
I would say the scientists viewed the issue not as a slowing down but as a situation where the North Atlantic waters were cooler due to an influx of colder water farther south into the Atlantic, shunting the warmer Gulf Stream farther south, thus resulting in colder air circulating over Europe precipitating the LIA.
I’d like them to study if the wobbling magnetic poles have any affect on climate and ocean currents. When you take a comb in the winter and fill it with static from your dry hair and run a small stream of water out of the tap and put move the comb close to the water, it pulls the water toward the comb. The magnetic poles wobble back and forth across the poles over the centuries and wonder if this has any affect on weather rotations and ocean currents.
These are from studies of proxies, but proxies are pretty much all we’ve got to look at past climate right?
There is evidence of the LIA in New Zealand. Here are just a couple of papers.
https://link.springer.com/article/10.1007/s00382-013-1876-8
There is evidence of a Medieval warm period in New Zealand
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.568.8271&rep=rep1&type=pdf
FYI. New Zealand is a country quite a long way from Europe.
Just like there is other research showing evidence of this from around the world.
So yeah, probably both events were global.
This paper seems to be revising the hoary old ‘we are gonna stop the gulf stream’ story.
I love Richard Lindzen’s take in this ( also involves some embarrassment of Bill Nye)
Or a paper trying argue that the LIA was just a regional event and only affected Europe
The 3000 year timeline of warm and cold periods – figure 4 above – is a very important and useful figure.
It was El Nino what done it….or did for the Minoans and Mayans anyway
https://www.clim-past.net/6/525/2010/cp-6-525-2010.pdf
The paper says COLD periods 700 and 1500 yrs ago affected the Atlantic Current, but then goes on to say our WARM phase will affect it, implying a bad effect. The last paragraph seems to have been tacked on to avoid losing their ‘climate cash’ funding.
Some actual science well done
“Significant finding: Study shows why Europe’s climate varied over the past 3000 years”
The study does show connections between oceanic oscillations and climate. But that does not seem to me to answer the question “why”.
The “why” is pretty obvious: “oceanic climate” is so named for a reason, oceanic oscillations are bound to impact climate.
As for the “why” there would be oceanic oscillations, well, that’ the way “dissipative systems” normally behave, just without any external forcing (*). https://en.wikipedia.org/wiki/Dissipative_system
(* although forcing can have some impact; for instance, you would experience circadian cycle even without daylight, but daylight keeps it in synchronicity with sun)
Of course, this now invokes the “chicken or the egg” scenarios