New Study Solves Long-Standing Mystery of What May Have Triggered Ice Age 101
nickwinlund77 shares a report from Phys.Org: A new study led by University of Arizona researchers may have solved two mysteries that have long puzzled paleo-climate experts: Where did the ice sheets that rang in the last ice age more than 100,000 years ago come from, and how could they grow so quickly? Understanding what drives Earth's glacial -- interglacial cycles -- the periodic advance and retreat of ice sheets in the Northern Hemisphere -- is no easy feat, and researchers have devoted substantial effort to explaining the expansion and shrinking of large ice masses over thousands of years. The new study, published in the journal Nature Geoscience, proposes an explanation for the rapid expansion of the ice sheets that covered much of the Northern Hemisphere during the most recent ice age, and the findings could also apply to other glacial periods throughout Earth's history.
About 100,000 years ago, when mammoths roamed the Earth, the Northern Hemisphere climate plummeted into a deep freeze that allowed massive ice sheets to form. Over a period of about 10,000 years, local mountain glaciers grew and formed large ice sheets covering much of today's Canada, Siberia and northern Europe. While it has been widely accepted that periodic "wobbling" in the Earth's orbit around the sun triggered cooling in the Northern Hemisphere summer that caused the onset of widespread glaciation, scientists have struggled to explain the extensive ice sheets covering much of Scandinavia and northern Europe, where temperatures are much more mild. [...] "Using both climate model simulations and marine sediment analysis, we show that ice forming in northern Canada can obstruct ocean gateways and divert water transport from the Arctic into the North Atlantic," [said Lofverstrom, an assistant professor of geosciences and head of the UArizona Earth System Dynamics Lab], "and that in turn leads to a weakened ocean circulation and cold conditions off the coast of Scandinavia, which is sufficient to start growing ice in that region."
"These findings are supported by marine sediment records from the North Atlantic, which show evidence of glaciers in northern Canada several thousand years before the European side," said Diane Thompson, assistant professor in the UArizona Department of Geosciences. "The sediment records also show compelling evidence of a weakened deep ocean circulation before the glaciers form in Scandinavia, similar to our modeling results." Together, the experiments suggest that the formation of marine ice in northern Canada may be a necessary precursor to glaciation in Scandinavia, the authors write. [...] "It is possible that the mechanisms we identified here apply to every glacial period, not just the most recent one," [Lofverstrom] said. "It may even help explain more short-lived cold periods such as the Younger Dryas cold reversal (12,900 to 11,700 years ago) that punctuated the general warming at the end of the last ice age."
About 100,000 years ago, when mammoths roamed the Earth, the Northern Hemisphere climate plummeted into a deep freeze that allowed massive ice sheets to form. Over a period of about 10,000 years, local mountain glaciers grew and formed large ice sheets covering much of today's Canada, Siberia and northern Europe. While it has been widely accepted that periodic "wobbling" in the Earth's orbit around the sun triggered cooling in the Northern Hemisphere summer that caused the onset of widespread glaciation, scientists have struggled to explain the extensive ice sheets covering much of Scandinavia and northern Europe, where temperatures are much more mild. [...] "Using both climate model simulations and marine sediment analysis, we show that ice forming in northern Canada can obstruct ocean gateways and divert water transport from the Arctic into the North Atlantic," [said Lofverstrom, an assistant professor of geosciences and head of the UArizona Earth System Dynamics Lab], "and that in turn leads to a weakened ocean circulation and cold conditions off the coast of Scandinavia, which is sufficient to start growing ice in that region."
"These findings are supported by marine sediment records from the North Atlantic, which show evidence of glaciers in northern Canada several thousand years before the European side," said Diane Thompson, assistant professor in the UArizona Department of Geosciences. "The sediment records also show compelling evidence of a weakened deep ocean circulation before the glaciers form in Scandinavia, similar to our modeling results." Together, the experiments suggest that the formation of marine ice in northern Canada may be a necessary precursor to glaciation in Scandinavia, the authors write. [...] "It is possible that the mechanisms we identified here apply to every glacial period, not just the most recent one," [Lofverstrom] said. "It may even help explain more short-lived cold periods such as the Younger Dryas cold reversal (12,900 to 11,700 years ago) that punctuated the general warming at the end of the last ice age."
Re: Putin (Score:2)
Blame Canada!
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America's Siberia
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work that headline (Score:5, Insightful)
so lets just lead with
because "may have" just really isn't that important in science, right?
Re:work that headline (Score:5, Informative)
so lets just lead with
because "may have" just really isn't that important in science, right?
A hypothesis is a 'may be' until it has been tested by observations, experiments or both and then peer reviewed. If it survives all attacks on it and is the best existing explanation for a particular phenomenon it becomes a scientific theory. That's literally how science works and no amount of bad wording in a Slashdot summary can change that.
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And that's not even the only issue.
The headline claims that the reason for the start of the ice age has been found, but even the Slashdot summary already makes abundantly clear that the reason why it started has been known or "known" for a while and that the new paper is about explaining why it hit Europe as hard as it did - i.e. harder than would normally be expected. (*) And it is not as if the paper is not 100% clear about that fact either. It literally says "The importance of Canadian Arctic Archipel
Socialist Canada freezes Socialist Scandanavia (Score:1)
Socialist Canada Freezes Socialist Scandinavians say Elitist "scientists".
There, I right winged the headline for you.
No longer a problem? (Score:1, Troll)
At least ice ages are no longer an issue.
Climate Scientists back in the 70's were worried sick about them back then.
Re:No longer a problem? (Score:5, Informative)
Took 2 posts to get to the first climate change denialist BS.
Name the "climate scientists" who were " worried sick" about ice ages.
You can't, because there were none. It's just a stupid straw man.
Those who said we were in an inter-glacial warming period, thought we might be back in an ice age IN THOUSANDS OF YEARS. No one was "worried" about that. And with the help of fossil fuels, all the natural climate cycles have been upended.
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Name the "climate scientists" who were " worried sick" about ice ages.
You can't, because there were none. It's just a stupid straw man.
Bullshit. I was 10 in 1980 and remember vividly all this climate bullshit. Feast your eyes.
https://www.climatedepot.com/2... [climatedepot.com]
I didn't put much effort in this. Just searched for "1970's ice age worries."
It was a scam then, it is a scam now, this whole Green thing. All to make money from the gullible who love to virtue-signal.
Remember kiddies, when reading agitprop from any source, always ask "Who stands to profit, if I do what it says to do in this article, or submit to their wishes? Who makes the cash?"
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From CSpan: Marc Morano is a former Republican political aide who founded and runs the climate change denial website ClimateDepot.com
Now get some valid references instead of repeating crap from right wing groundnuts.
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So all of those actually written and published stories aren't valid because... a Republican made a website that collected them all? And you're calling him a groundnut?
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So all of those actually written and published stories aren't valid because.
So to be clear, to you the bar for accuracy is "written and published"? Here's something written and published for you, "DirkDaring is a Dumbfuck who should fuck off immediately." There, it must be true!
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You have a serious reading comprehensive problem, and you shouldn't be resulting to personal childish attacks until at least the third response when losing an argument. Get with the program man.
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You have a serious reading comprehensive problem
I responded to what you wrote. If what I responded with doesn't make sense to you, then write what you meant to write instead of some other bullshit.
and you shouldn't be resulting to personal childish attacks
It's not an attack if it's true as truth is an absolute defense against libel or slander in the USA, and it's published, so it must be true right?
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When they are *selling* a DVD called "Climate Hustle 2 - Rise of the Climate Monarchy" for $19.95 with a picture of Kevin Sorbo on the cover it doesn't exactly inspire confidence in their scientific rigor.
It is very clear from the supplemental articles that this website has an agenda to be sure and a conspiratorial one at that outside of climate science. Does that make their analysis wrong? No, not at all, but it should arouse suspicion in you just as much as a site with definite left wing environmental hi
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Now get some valid arguments instead of relying at ad-hom
Re: No longer a problem? (Score:5, Interesting)
It's this sort of argument that's always the problem across scientific disciplines - finding conclusions from when the science was in its infancy, and using it as an example how wrong the whole field can be. And if they were wrong back then, why ever trust them again?
Back in the 1950's there were doctor-recommended cigarettes. And now doctors say they're bad for you! Why trust doctors ever again?
You can point to times when people predicted an ice age, but the reality is that the majority of climate studies back then were still predicting warming. This is a literature review of the "cooling" vs "neutral" vs "warming" claims in the 70's.
https://journals.ametsoc.org/d... [ametsoc.org]
By the mid 70's there was a pretty clear consensus amount climatologists that it would not be a cooling trend.
Incidentally, spot checking those articles you link to, most of them have the concept for the aerosol-induced cooling mechanism correct, but omit or underestimate the greenhouse gas impact (except for one I could find). Climate forcing can warm or cool, and understanding those competing effects required more data and better models. Once both of those things developed the picture became much clearer - the warming greenhouse impact would surpass the cooling aerosol impact.
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Back in the 1950's there were doctor-recommended cigarettes. And now doctors say they're bad for you! Why trust doctors ever again?
Very good point. Never trust a single group based on how "important" or "smart" they are. Many people from honored professions are paid to have opinions.
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Unfortunately, this heuristic can be exploited. I would say pick "smart" and "important" experts and be careful about how they are funded. Also don't give unjustified value to the default/current/null situation. In particular, doing nothing can often be much worse than the expert recommendation.
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Another consideration is that we largely fixed the global dimming that was predicted to cool things down. Coal becoming cleaner was a big thing along with other measures to limit air pollution and even today global warming is offset somewhat by coal burning in places like China as well as things like forest fires.
We could also have increasing volcano-ism which would also cool things down while it lasted
Re: No longer a problem? (Score:2)
True, although the long term warming effect from coal CO2 emissions is generally larger than the short term cooling effect from its aerosol emissions. So in any (accurate) model, stopping coal burning altogether will reduce global temperatures.
The aerosols are regional forcers because they don't last long - days, vs decades for CO2. So they can have a short, regional cooling effects that are greater than the CO2 warming. But the CO2 will hang around for many years across the planet, resulting in net heatin
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Yes, CO2 has a long half life in the atmosphere. IIRC, the problem with the early climate models was underestimating the future CO2 levels and therefore showed the effects of aerosols as greater.
IIRC, a while back they reran the early climate models with accurate CO2 levels and then they were much more accurate. it's hard predicting the future, just takes one variable being wrong to screw up predictions.
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Name the "climate scientists" who were " worried sick" about ice ages.
You can't, because there were none. It's just a stupid straw man.
Bullshit. I was 10 in 1980 and remember vividly all this climate bullshit. Feast your eyes.
https://www.climatedepot.com/2... [climatedepot.com]
I didn't put much effort in this. Just searched for "1970's ice age worries."
I was 10 in 1970 and I remember the ice-age scares.
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I was 15 and remember the terror of the dinosaurs.
Re:No longer a problem? (Score:4, Interesting)
I was 10 in 1965 and I remember the warnings about CO2-caused warming.
I was in my 20s in the late 70s and early 80s when there were several severe winters in North America.
The Milankovitch cycles were beginning to be understood better and popularized then, and we were near a glacial minimum, so the expectation was that ice was coming back in the next few thousand years or ten. Also, there were a few studies showing that a glaciation cycle could begin very rapidly. So naturally the popular press added sensationalism to the weather reports by talking about ice ages and glaciation.
But I still remember hearing about global warming studies during the 70s and 80s.
(BTW, technically we are in an ice age now, as we have been for all of human's existence, just closer to a glacial minimum than maximum.)
Re: No longer a problem? (Score:3)
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I believe you are presenting the evidence in a misleading way.
The period of peak concerns about global cooling was in the early 1970s. While CO2 was a concern, the fear was that aerosol pollution would be the dominant force, causing global cooling similar to how large volcanic eruptions can cause a cooling effect.
As more data was collected, the dominant factor was determined to be CO2, not aerosols.
So basicall
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Actually, we cleaned up most of the pollution and the sunlight-reflecting particles rapidly dissipated, so there was no chance for there to be a competition between aerosols and CO2 to see which would have prevailed.
Re: No longer a problem? (Score:2)
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Remember kiddies, when reading agitprop from any source, always ask "Who stands to profit, if I do what it says to do in this article, or submit to their wishes? Who makes the cash?"
Good thing energy companies don't know about this.
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These all look to be news articles not research papers. If you really want to claim this you have show this was a scientifically accepted idea, and not just some speculative hypothesis. I'm not saying you're wrong, but you haven't established you're right. I'm not surprised the media would be all over a theory like this. They would also sensationalize and dumb it down. What did the scientists themselves say. Probably nothi
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Bullshit. I was 10 in 1980 and remember vividly all this climate bullshit. Feast your eyes.
And I was 14, and had learned about global warming 4 years before: idiot
Re:No longer a problem? (Score:4, Interesting)
Read The Long Thaw by David Archer. The next glacial advance should start in no more than 3000 years. But 400 ppm CO2 might be enough to stop it.
Technically we are still in an ice age, though in an interglacial period. The previous interglacial was warmer than this one, you can look that up.
The warmest period of the current interglacial was about 6000 years ago. We are not even back to that.
https://en.wikipedia.org/wiki/... [wikipedia.org]
Re: No longer a problem? (Score:2, Insightful)
Name the "climate scientists"
It's a trick question. There were no "climate scientists" in the 1970s. There were meteorologists and physicists. But "climate science" is a recent development. Created when the hard sciences were not providing politically correct answers.
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"climate science" is a recent development. Created when the hard sciences were not providing politically correct answers.
Climate science is a recent development, created as science advanced. Except that's not true, either. It's not all that recent [nasa.gov] as science goes. What it's done is developed as we realized a need for a broader examination, which happened as a result of advances in science.
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There were no chemists in medieval times, either. There were alchemists and apothecaries. "Chemists" are a recent development, created when the hedge wizards and witches were not providing ways to make money for Big Pharma.
Idjit. :P
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not providing ways to make money for Big Pharma
So who's profit motive are the climate scientists working for?
Re: No longer a problem? (Score:2)
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Yes. And meteorologists studied it.
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I'm not sure what point you are trying to prove.
We still don't understand the Earth's climate.
Global warming is a well-established fact with a long history of being studied.
Just don't get run over by a glacier while you are busy running your latest computer model.
Nostradamus was right about a number of things.
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We still don't understand the Earth's climate.
Perfectly, down to the regional level in all circumstances? No, but we do a pretty good job overall now. Occasionally, there are surprises in detail as exact tipping points of all phenomena cannot be predicted, but that's not necessarily a case of not understanding it. I can show you an understanding of probability and physics, but I still can't predict the result of a coin toss, but I can very likely tell you how many heads you will have after tossing one 10,000 times.
Just don't get run over by a glacier while you are busy running your latest computer model.
The computer models are pretty accurat
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Perfectly, down to the regional level in all circumstances?
I'd say that overlooking a process which could lead to half the globe being covered by a sheet of ice is a pretty significant circumstance.
The computer models are pretty accurate these days.
For a very limited set of conditions. Extrapolation [xkcd.com] will only get you so far. Particularly with highly nonlinear, chaotic systems. Identifying the "tipping points" is useless when one doesn't recognize the futility of the modeling problem in the first place.
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I'd say that overlooking a process which could lead to half the globe being covered by a sheet of ice is a pretty significant circumstance.
It would, but that is not what has happened. Some details of the effects on about 5% of the globe is what we are talking about here, and nowhere near 50%.
The computer models are pretty accurate these days.
For a very limited set of conditions.
That's a misunderstanding of how modelling works.
The modelling is not futile. In fact so far it has been rather accurate, however, it cannot necessarily know of the past existence of an ice dam stopping water getting to the Atlantic.as there is a probability to it actually forming. That probability can be modelled. However, it was sufficient to indicate th
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Took 2 posts to get to the first climate change denialist BS.
Name the "climate scientists" who were " worried sick" about ice ages. You can't, because there were none. It's just a stupid straw man.
Those who said we were in an inter-glacial warming period, thought we might be back in an ice age IN THOUSANDS OF YEARS. No one was "worried" about that. And with the help of fossil fuels, all the natural climate cycles have been upended.
I was born in the 1970s and remember talk of an impending ice age [wikipedia.org]. The 11 Jan 1970 Washington Post had a headline "Colder Winters Held Dawn of New Ice Age".
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"This is an interesting document. As usual, it was brought to my attention by a skeptic, who misrepresented it. This is common, but why? My best guess is false-memory. In weather, vol 58, august 2003, p 311, M R Morgan says: "...recall the concern that we conveyed to the public, particularly during the 1970's, when after over 30 years of cooling we we
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You probably remember the newspaper journalists misinterpretation of it all, i certainly do
As I said, I was born in the 1970s. I wasn't old enough to regularly read the newspapers. I remember TV newscasts. My dad had a PhD in ecology, so I remember him discussing it, but specifics are hazy. The point I wanted to make is there was talk of returning to an ice age in the 1970s and early 1980s. People cited what they believed to be credible scientists. Then, like now, very few laymen went direct to scientific papers, instead relying on journalists to translate technical jargon into something the mas
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Then, like now, very few laymen went direct to scientific papers, instead relying on journalists to translate technical jargon into something the masses can understand.
Then, unlike now, very few laymen had any chance of accessing scientific papers at all. They were printed in paper journals which were kept in university libraries which by and large were not generally open to the public. The masses had little choice except to accept the (mis)translations of journalists.
Times, they are a'changin'. For the first time in the centuries since scientific journals were established as a concept and a general practice, the masses can access their contents directly, either becaus
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Having lived through the 1970ths I have to agree, there was some consent about high potential of an ice age over the next 100-200 years. That thesis even made it into popular media quite a lot.
This was mostly based on older finding from back to the 1930ths when climate scientists where mostly focused on older small ice ages like the https://en.wikipedia.org/wiki/... [wikipedia.org] which repeated regularly.
But as one can see in the linked Wikipedia this should be of the table for good. People back then simply didn't fully
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Having lived through the 1970ths I have to agree, there was some consent about high potential of an ice age over the next 100-200 years. That thesis even made it into popular media quite a lot.
There was zero scientific consensus for one in that time period. Quite the reverse. It made it into the popular media, but was not supported by science.
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The most intriguing theory I've read so far is that we are, in fact, several centuries into conditions that, prior to human activity, WOULD in fact have set up the right conditions for the earth to be cooling right now. Or, put more bluntly, "the start of the next ice age". The author's theory went something like this:
* AGW is measurably warming the earth
* The earth is nevertheless a little cooler than everybody's models say it OUGHT to be (at least, if you assume we're still in an interglacial period)
* The
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At least ice ages are no longer an issue.
Climate Scientists back in the 70's were worried sick about them back then.
That was back when they had to go outside and use pencil and paper to write down thermometer readings in a handful of places then type it up and send it in envelopes with stamps on.
Now we have high-resolution satellites with global coverage and supercomputers to collect all the data.
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That never happened.
There was some articel in a popular science mag, and an interview on TV about the topci, and thats it.
In other words... (Score:5, Funny)
In other words: Blame Canada!
Re:In other words... (Score:5, Funny)
Sorry!
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I'm not your buddy, guy!
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I'm not your guy, pal!
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I'm not your pal, buddy!
Proper title. (Score:3)
New Study Sheds Light on Long-Standing Mystery of What May Have Triggered Ice Age
You haven't solved the long standing mystery if the result isn't a certainty.
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Welll.. ..that's a bit harsh. This MAY be the correct solution. If so, then it *is* the correct solution, and they've solved the problem. They just haven't proved that they've solved the problem. (And they admit it.)
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This MAY be the correct solution.
Then what they have is a theory.
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Theories are all science can ever produce. If you want proofs, stick to math.
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You still upset that the CDC changed the definition of vaccine?
So what happens when the currents stop? (Score:3)
The conveyor is slowing down. Powered in part by sea ice, it may actually stop. What's that do to climate?
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Based on what?
Based on the fact that you like it because it absolves you of any personal responsibility?
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What should be my, or anyone, responsibility for something that happened 100.000 years ago?
To learn from it if you want to claim to be intelligent and care about facts.
Otherwise, carry on in willful ignorance. You're doing a grate job.
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What should we learn exactly? That sun caused some events on the earth that caused an ice age?
What the likely outcomes are if certain conditions come into being.
Then what? Stop the sun from causing events?
An intelligent person might suggest understanding cause and effect well enough to engage in mitigation strategies, which I understand is why you didn't think of that.
Do you people think you have some godly super powers or what?
Yes. In fact we do have some "godly super powers". We can do many things today that were formerly considered the domain of god, and we are learning to do more of them. You want to sell the human race short so that you can believe we can't fix these problems we've created, becaus
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Re: Putting my money (Score:3)
Takeaway message (Score:3)
The takeaway message is that earth's climate and what drives it is still poorly understood.
Re: Takeaway message (Score:3)
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To me the take away is that we could alter the water in Canada and cause an ice age. Sounds like a good James Bond story to me.
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To me the take away is that we could alter the water in Canada and cause an ice age. Sounds like a good James Bond story to me.
Sounds slightly less stupid than the James Bond movie about stealing water. But only slightly.
Pure speculation (Score:1)
Solved Exactly What? (Score:1)
The current Quaternary Ice Age began 2.6m years ago and is part of a longer 55m year cooling trend with the last 5m years having rapid cooling. What they mean is the cause of the last glacial,however they've got that wrong because the cycle of glacials and interglacials is driven by changes in Orbital Forcing. 110kya the planet was actually as warm or maybe a bit warmer than it is now. What they are showing is that as the planet cooled, ice sheets formed first in Canada, this caused a change in ocean curre