Ice Age.

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neverfail
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Ice Age.

Post by neverfail » Sun Jun 11, 2017 2:23 am

http://www.abc.net.au/news/science/2016 ... er/7185002

What is an ice age?
Key points:

The last ice age was 12,000 years ago
At that time the sea level was 120m lower than today
The onset of an ice age is related to changes in the Earth's tilt and orbit
The Earth is due for another ice age now but climate change makes it very unlikely
An ice age is a time where a significant amount of the Earth's water is locked up on land in continental glaciers.

During the last ice age, which finished about 12,000 years ago, enormous ice masses covered huge swathes of land now inhabited by millions of people.

Canada and the northern USA were completely covered in ice, as was the whole of northern Europe and northern Asia.

At the moment the Earth is in an interglacial period - a short warmer period between glacial (or ice age) periods.

The Earth has been alternating between long ice ages and shorter interglacial periods for around 2.6 million years.

For the last million years or so these have been happening roughly every 100,000 years - around 90,000 years of ice age followed by a roughly 10,000 year interglacial warm period.

neverfail
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Re: Ice Age.

Post by neverfail » Sun Jun 11, 2017 3:03 am

Some scientists still believe (probably reflecting their own narrow field of scientific research) that ice ages were caused by shortfalls of solar heat reaching the Earth's surface for prolonged periods of time. I absolutely reject that hypothesis as the geological and palaeontology evidence stacks up against it. If the solar energy shortfall theory were true you would have expected the drop in temperatures to have been fairly evenly distributed across the Earth; but it was not so. To begin wit, there is no evidence of any significant temperature drop in the lands close to the equator - which is why a biodiversity of plants sensitive to cold temperatures continued to survive and prosper around the Earthy's equator bulge. But more than that even in today's high latitude and some sub-Arctic regions temperatures did not chill down but might have even warmed up:

https://www.newscientist.com/article/mg ... t-ice-age/

Siberia was a wildlife refuge in the last ice age

I was first alerted to the maldistribution of the effects of Ice Age glaciation even in the high latitudes of the northern hemisphere years ago by a Russian internet colleague resident in Irkutsk, eastern Siberia. He informed me of research work done in the Lake Baikal region on drilled sediments dating from the period that were prodigious with fossilised pollen from plants that today are found only in the Mediterranean basin. In other words, the Irkutsk/Lake Baikal region of Siberia had a regional climate considerably WARMER and more benign than today's.

How come? I have always found it weird that the two great ice sheets of the Ice Age era formed on either side of the North Atlantic respectively over 1. Canada- Greenland and parts of north eastern United States and 2. the British Isles-North Sea- Scandinavian peninsula and Baltic Sea region. Considering its high latitude location and vast landmass (land always chills down more than adjacent ocean water) Siberia should normally have been for the most massive Ice Age glaciation; yet in fact its climate was warmer.

It all adds up to a prolonged tilt in the earth's axis of rotation having been the cause of the Ice Age.

The Earth must have tilted in a way that brought the northern reach of the Atlantic Ocean much closer to the North Pole than now and eastern Siberia correspondingly further away from it.

Is we are due for another ice age soon due to another periodic "wobble" of the earth into a new rotational axis then it means that we humans are powerless to stop it happening. Wen can only roll with the punches just like our remote ancestors did over 100,000 years ago.

When it happens it will make our present day concerns about global warming due to greenhouse gas emissions look like so much meaningless gibberish.

neverfail
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Re: Ice Age.

Post by neverfail » Sun Jun 11, 2017 4:41 am

Try to imagine, if you would, a world in which the north rotational pole had shifted from its present day location approximately in the middle of the Arctic Sea to a point in the Ocean just to the north of Iceland. Obviously, the entire Arctic circle has to correspondingly shift in sympathy. So which lands are now incorporated within this newly located Arctic circle?

Its southern extremity would be at a point in the mid-Atlantic about level with the north (Biscay) coast of Spain. As you follow the curve of the circle northeast you find that (respectively) the British Isles; the Netherlands; the North sea: Scandinavia, the Baltic Sea and the lands fringing it are all incorporated to within that circle. Then very lands covered by the northern Europe ice sheet during the last ice age.

Move across now to the opposite side of the North Atlantic and the western side of the circle cuts through the extreme northeastern USA; the Greeat Lakes; Ontario Provence in Canada: most of Hudson Bay and Greenland: the very region buried underneath the North American ice sheet.

Make sense, reader?

https://wattsupwiththat.files.wordpress ... ce-age.jpg

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Re: Ice Age.

Post by SteveFoerster » Sun Jun 11, 2017 7:38 am

The spin pole does move slightly based on mass redistribution of ice and water from climate changes, but that movement is something like ten meters per century, and doesn't explain why some areas fare better than others during ice ages.
Writer, technologist, educator, gadfly.
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Doc
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Re: Ice Age.

Post by Doc » Sun Jun 11, 2017 8:43 pm

Global wind and ocean current patterns seem to have with driven climate change than the Earth's spin axis. Seems like I read some were that Earth's biggest ice ages happened during geologic times when the continents were bunched up together. Thus restricting the winds over land and changing the local climate. The Earth's climate is a non linear dynamic system where local weather in one place effects the local weather in places far away. As a non linear dynamic system all the parts count. Scientific reductionism inherently does not work very well in making predictions about the future because of it. At best it can only give odds of something happening and those odds can be completely wrong. Today your odds of being killed by a meteor are slightly higher than being hit by lightning. Tomorrow a 100 meteor hits a major city and the odds of you being killed are greater than being killed in a car accident. A 1 mile dia meteor hits the Earth and and your odds of being killed by a meteor are greater than you dying of old age. It all depends on how exactly the measure of the whole is made. If the measurement is not made to an exactness to a point beyond what human science is capable of, then predictions are just predictions based on the odds. In the case of the weather AT BEST they are only good for a few days.

https://en.wikipedia.org/wiki/Butterfly_effect#History
Lorenz wrote:

"At one point I decided to repeat some of the computations in order to examine what was happening in greater detail. I stopped the computer, typed in a line of numbers that it had printed out a while earlier, and set it running again. I went down the hall for a cup of coffee and returned after about an hour, during which time the computer had simulated about two months of weather. The numbers being printed were nothing like the old ones. I immediately suspected a weak vacuum tube or some other computer trouble, which was not uncommon, but before calling for service I decided to see just where the mistake had occurred, knowing that this could speed up the servicing process. Instead of a sudden break, I found that the new values at first repeated the old ones, but soon afterward differed by one and then several units in the last decimal place, and then began to differ in the next to the last place and then in the place before that. In fact, the differences more or less steadily doubled in size every four days or so, until all resemblance with the original output disappeared somewhere in the second month. This was enough to tell me what had happened: the numbers that I had typed in were not the exact original numbers, but were the rounded-off values that had appeared in the original printout. The initial round-off errors were the culprits; they were steadily amplifying until they dominated the solution." (reference 5, page 134)|[8]
People in general are of terrified of the uncertainty of existence. Which in understandable. They want to make plans for their future and have good outcomes. But this is not the way the universe works.

The reason people get upset with things like global warming is based on fear of that uncertainty. During WWII there were "paper drives" in the US to "help" with the war effort. The only thing those paper drives did to help the war effort was to give people they were doing something outside their normal existence to "help" And this was certainly a cynical attempt to prevent people from feeling helpless.

There is probably a once in a google of light years chance that the quantum wave of the moon will disappear from its current position of orbiting the earth and re-appear on the other side of the universe. The effect of which on the earth likely could be that the climate stopped changing enough to support life on Earth.

As my father once told me 'You make your plans about your life, then life happens"

Which roughly translates into "Learn to Stop Worrying and Love the Bomb"
The classes and the races to weak to master the new conditions of life must give way {..} They must perish in the revolutionary holocaust --Karl Marx

neverfail
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Re: Ice Age.

Post by neverfail » Mon Jun 12, 2017 2:50 am

Welcome to this discussion Steve and Doc. Glad to see your posts as I I was a little worried that this topic to be a solo effort.

neverfail
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Re: Ice Age.

Post by neverfail » Tue Jun 13, 2017 3:39 am

Doc wrote:
Sun Jun 11, 2017 8:43 pm
Global wind and ocean current patterns seem to have with driven climate change than the Earth's spin axis. Seems like I read some were that Earth's biggest ice ages happened during geologic times when the continents were bunched up together. Thus restricting the winds over land and changing the local climate. The Earth's climate is a non linear dynamic system where local weather in one place effects the local weather in places far away.
Doc, I want to earnestly thank you for your contribution. I must also beg to differ.

The Ice Ages (there have been several in succession) began only around around 2.4 million years ago when spatially the relationship between the continents was about the same as now. This is something that I myself have learned only since I inaugurated this discussion as I had previously thought they had begun much earlier. Well, it seems I still have things to learn.

https://www.cdm.org/mammothdiscovery/wheniceages.html

(No offence intended that I quoted from a children's museum website. It is just this is the most succinct definition I could find on-line at short notice.)

The last time that the continents were bunched up together was when the the supercontinent of Pangaea existed over 175 million years ago - at a time when the dinosaurs probably ruled the earth.

https://www.cdm.org/mammothdiscovery/wheniceages.html

That supercontinent, located in the Earth's southern hemisphere, then progressively broke apart with Eurasia and then North America on their respective tectonic plates breaking away first followed by Africa. This left a residual supercontinent about half the size known as Gondwanaland. Then South America, India broke away with South America drifting northwest (to eventually link up with North America) and India and Australia (both are on the same tectonic plate) drifting north at high speed. India crashed into the southern side of Asia throwing up the Himalaya range.

Antarctica remained in exactly the same location it was at when it formed the core of Pangaea (still is) and then Gondwanaland. In those days it was not ice covered like it is now but apparently had a relatively benign low temperate climate that allowed it to have been well vegetated with forest cover and was the home of dinosaurs - cold blooded reptiles that would have needed some solar warmth in order to function.

By the time Australia finally broke away from Antarctica the Jurassic era was already in the distant past and mammals ruled the earth. But these were not the familiar placental mammals that make up most of the Earth's mammal stock today but predecessor marsupials and monotremes . Because of long isolation Australia is today the sole heir to the zoological legacy of Gondwanaland.

As you may now see doc the Ice Ages did not occur when Pangaea existed. However, I note that the Earth's biggest ice sheets of the ice ages formed in the Northern hemisphere; not the southern one where the ice sheets (excluding Antarctica) were generally small and scattered. But the bulk of the Earth's continental masses having drifted far north from their point of origin are now in the northern hemisphere and in imminent danger of "bunching up together" again; almost like Pangaea reborn in a northerly location.

Cheers!

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Doc
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Re: Ice Age.

Post by Doc » Tue Jun 13, 2017 6:38 am

neverfail wrote:
Tue Jun 13, 2017 3:39 am
Doc wrote:
Sun Jun 11, 2017 8:43 pm
Global wind and ocean current patterns seem to have with driven climate change than the Earth's spin axis. Seems like I read some were that Earth's biggest ice ages happened during geologic times when the continents were bunched up together. Thus restricting the winds over land and changing the local climate. The Earth's climate is a non linear dynamic system where local weather in one place effects the local weather in places far away.
Doc, I want to earnestly thank you for your contribution. I must also beg to differ.
Stop right there

What I said
Earth's biggest ice ages
[/u]


The Ice Ages (there have been several in succession) began only around around 2.4 million years ago when spatially the relationship between the continents was about the same as now. This is something that I myself have learned only since I inaugurated this discussion as I had previously thought they had begun much earlier. Well, it seems I still have things to learn.

https://www.cdm.org/mammothdiscovery/wheniceages.html

(No offence intended that I quoted from a children's museum website. It is just this is the most succinct definition I could find on-line at short notice.)

The last time that the continents were bunched up together was when the the supercontinent of Pangaea existed over 175 million years ago - at a time when the dinosaurs probably ruled the earth.

https://www.cdm.org/mammothdiscovery/wheniceages.html

That supercontinent, located in the Earth's southern hemisphere, then progressively broke apart with Eurasia and then North America on their respective tectonic plates breaking away first followed by Africa. This left a residual supercontinent about half the size known as Gondwanaland. Then South America, India broke away with South America drifting northwest (to eventually link up with North America) and India and Australia (both are on the same tectonic plate) drifting north at high speed. India crashed into the southern side of Asia throwing up the Himalaya range.

Antarctica remained in exactly the same location it was at when it formed the core of Pangaea (still is) and then Gondwanaland. In those days it was not ice covered like it is now but apparently had a relatively benign low temperate climate that allowed it to have been well vegetated with forest cover and was the home of dinosaurs - cold blooded reptiles that would have needed some solar warmth in order to function.

By the time Australia finally broke away from Antarctica the Jurassic era was already in the distant past and mammals ruled the earth. But these were not the familiar placental mammals that make up most of the Earth's mammal stock today but predecessor marsupials and monotremes . Because of long isolation Australia is today the sole heir to the zoological legacy of Gondwanaland.

As you may now see doc the Ice Ages did not occur when Pangaea existed. However, I note that the Earth's biggest ice sheets of the ice ages formed in the Northern hemisphere; not the southern one where the ice sheets (excluding Antarctica) were generally small and scattered. But the bulk of the Earth's continental masses having drifted far north from their point of origin are now in the northern hemisphere and in imminent danger of "bunching up together" again; almost like Pangaea reborn in a northerly location.

Cheers!
https://en.wikipedia.org/wiki/Paleozoic#Geology
The Paleozoic era began and ended with supercontinents and in between were the rise of mountains along the continental margins, and flooding and draining of shallow seas between.[clarification needed] At its start, the supercontinent Pannotia broke up. Paleoclimatic studies and evidence of glaciers indicate that central Africa was most likely in the polar regions during the early Paleozoic. During the early Paleozoic, the huge continent Gondwana (510 million years ago) formed or was forming. By mid-Paleozoic, the collision of North America and Europe produced the Acadian-Caledonian uplifts, and a subduction plate uplifted eastern Australia. By the late Paleozoic, continental collisions formed the supercontinent of Pangaea and resulted in some of the great mountain chains, including the Appalachians, Ural Mountains, and mountains of Tasmania.
The Earth's BIGGEST ice Age (note the singular) nearly ended life on the Earth.

https://en.wikipedia.org/wiki/Huronian_glaciation
The classes and the races to weak to master the new conditions of life must give way {..} They must perish in the revolutionary holocaust --Karl Marx

neverfail
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Re: Ice Age.

Post by neverfail » Tue Jun 13, 2017 5:38 pm

Doc wrote:
Tue Jun 13, 2017 6:38 am

The Earth's BIGGEST ice Age (note the singular) nearly ended life on the Earth.

https://en.wikipedia.org/wiki/Huronian_glaciation
Very well Doc. But you realise this earlier Ice Age that occurred at the birth of terrestrial life is outside the terms of reference with which I began this discussion, don't you?

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Doc
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Re: Ice Age.

Post by Doc » Tue Jun 13, 2017 8:08 pm

neverfail wrote:
Tue Jun 13, 2017 5:38 pm
Doc wrote:
Tue Jun 13, 2017 6:38 am

The Earth's BIGGEST ice Age (note the singular) nearly ended life on the Earth.

https://en.wikipedia.org/wiki/Huronian_glaciation
Very well Doc. But you realise this earlier Ice Age that occurred at the birth of terrestrial life is outside the terms of reference with which I began this discussion, don't you?
My point is it is in the winds and the currents as much as anything.
The classes and the races to weak to master the new conditions of life must give way {..} They must perish in the revolutionary holocaust --Karl Marx

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