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Abrupt Climate Change

Re: Abrupt Climate Change

Unread postby jedrider » Sun 08 Jan 2017, 10:48:29

Newfie wrote:So Plant how would you define abrupt? Under 20 years? Or is 100 good enough?


I know you are trolling each other. However, if abrupt climate change is normal, then what of ABRUPT climate change (convenient that I like to use CAPS often -- is this just a tic of mine, though)?

Maybe, we'll sort of know when the signal of ABRUPT climate change becomes obvious, that McPherson is right in his assessment.
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Re: Abrupt Climate Change

Unread postby Plantagenet » Sun 08 Jan 2017, 11:02:16

jedrider wrote:
Newfie wrote:So Plant how would you define abrupt? Under 20 years? Or is 100 good enough?


I know you are trolling each other.


That's BS jedrider. I'm not trolling anyone.

There really are multiple examples of large and Abrupt global Climate change in the paleoclimate record and it's not impossible we'll get another one as we continue to pump CO2 and CH4 into the atmosphere

Cheers!

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Re: Abrupt Climate Change

Unread postby Tanada » Sun 08 Jan 2017, 11:32:36

dohboi wrote:T: 'climate stability' is a relative term.

You always have to say, 'compared to what.'

The holocene climate was 'unstable' compared to a fictitious ideal of an absolutely unchanging climate.

Holocene climate was very stable compared to periods of shifts from glacials to interglacials (and back), and compared to most other interglacials--and especially compared to what we are heading into now.

Those, to me and I think to most, are the more relevant comparisons to make, wouldn't you say.

But yeah, the only place where climate is completely stable is basically someplace like the moon which is very consistent in not having a climate (in most senses) at all! :-D



Again dohboi you are the victim of bimodal thinking. The way you look at it things are either 'warm interglacial' or 'cold glaciation'. The actual picture is vastly more complex than a simple ice/warm viewpoint presents. Here look at this, it is one page and fits your screen nicely on a desktop computer,
http://www.gly.uga.edu/railsback/Fundam ... ages01.pdf
Focus in on the left end of the graph between Termination I and Termination II.
This segment is the 100,000 years between the last glaciation and the previous interglacial. Notice anything? Yes indeed, about 115,000 years ago a new cooling period began bottoming out with 5D at about 105,000 years ago. Then the climate warmed up to 5C and wobbled around that plateau for about 7500 years, then dipped again to 5B before bouncing back to 5A for about 7500 years.

Not only was the climate of 5E, 5C and 5A all conducive to agriculture with the same crops we grow now, the periods were each long enough for humans to discover agriculture and develop it quite extensively. But we didn't. It was only after we progressed to Terminus I that someone got around to developing agriculture, in at least three and possibly as many as five different locations. We are certain it happened in China with Rice, Mesoamerica with Maize, and Ur (Iraq) with Wheat and Barley. It is also suspected to have happened in Peru with Potato and the Ganges River Valley (India) but there is argument about whether these cultures developed agriculture independently, or got the idea from neighbors who had already started the practice with other crops. Once the first plant was domesticated each culture tried domesticating all kinds of plants in their area and because of that we have about 250 different plant species that we currently or in the last 12,000 years have grown as crops.

Now go back and look at that last 100,000 years again and look close, those 7500 year wiggles have smaller variations as well. About 18,000 years ago we hit the big 100,000 year wiggle and the major glacial sheets in Scandinavia and Asia and North America began to collapse. Right at that time the current Sahara Desert was a lush green savanna with rivers and lakes and patches of forest here and there where people had a great time hunting and fishing and gathering wild plants. There was absolutely no reason all that vast prairie could not have been farmed much as Iowa is today, but nobody had invented agriculture yet. We know about the people who lived there from Archeology, they left behind lithographs on rocks we can view easily, and we have dug up fishing villages and such on the old lake shore of what is now barren desert.

See that is what I am trying to communicate to you here, climate change has been shaping our cultures for all of the last 100,000 years. During those warm 5C and 5A periods our ancestors spread all over Africa. Then around the end of 5A the Toba eruption in Indonesia dropped a Volcanic Winter on top of the already generally cool conditions and squeezed our population through a truly brutal population bottleneck nearly causing us to go extinct. Genetic studies support the idea that only a very small number of our species made it through the bottleneck, and the generally cold glacial conditions certainly didn't help. But between that event circa 75,000 years ago and 50,000 years ago our population recovered, and then even though it was the depths of the ice age when the 3C warm period arrived the population exploded and spread, east to Asia via the Arabian Peninsula to Persia to Pakistan into India and eventually finding our way to Australia 45,000 years ago. The second grouping went north, across the Gibraltar Strait and through the middle east via Israel, Turkey and Greece. there is disputed evidence that the middle eastern occupation began as early as 70,000 years ago but the commonly accepted figure is more often 55,000 years ago. Either way those few survivors of the Toba eruption had fully reoccupied Africa's easy living zones by a few thousand years after near extinction. We still stubbornly clung to the hunter gatherer lifestyle until the warming between 22,000 and 18,000 started changing the climate of Africa forming the Sahara Desert and making migrations between groups difficult. It is frequently argued that the drying climate forced the hunter gatherer population to concentrate into the river valleys and that is what lead to the agricultural invention period around the great rivers in regions that had been lush but which were becoming drier as the climate zones shifted.

At no time in the last 100,000 years was there a 'stable climate conducive to agriculture' there have just been periods when it was easier to practice and harder to succeed at. If Agriculture had been invented during the 5E/Terminal II period it would have still been practiced widely in the 5C and 5A periods and remnant pockets wherever possible in all the rest. Agriculture needs a local climate warm enough to support plant growth and enough moisture to provide the needs of the plants. Add a little dirt and knowledge and you can farm any time you have warm enough conditions with the requisite water supply.

I will even go a step further, if Agriculture had been invented around 5E it would be mostly based on tropical plants today because those plants would have weathered the ice age all the way around the equator wherever people were growing them. It is also likely if tropical agriculture had developed before the last ice age began at the end of 5E the human population would have been 5-10 times larger and much more genetic variation would have made it through the Toba bottleneck because there is a high probability they would have spread themselves at least across Africa/Asia/Australia in the 25,000 years between the invention and Toba eruption. Instead of being a small population of hunter-gatherers isolated in Africa we would have been spread over 3.5 continents some places of which were not terrible living conditions even after Toba erupted.

So you ask 'compared to what' and I say compared to the last 100,000 years, not just the 12 percent everyone prefers to focus on after agriculture was invented.
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Re: Abrupt Climate Change

Unread postby dohboi » Sun 08 Jan 2017, 13:16:01

Interesting graph and speculations (though I'm not sure the former supports the latter as much as you imply).

I somehow missed that this was a discussion about when ag could have arisen. Probably the main limiting factor for it developing during "5E" was that human language probably had not yet developed into its fully nuanced modern form yet, humans could not have communicated and coordinated in a way to pass on all the requisite knowledge. On the other hand, fairly sophisticated stone tool technologies did get passed down in this and earlier periods, so who knows?

On your claim about the tropics, why do you think that ag (in the sense of fairly extensive fields of monoculture, not just gardens/horticulture) did not develop first in the tropics of sub-Saharan Africa?
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Re: Abrupt Climate Change

Unread postby vtsnowedin » Sun 08 Jan 2017, 14:01:37

dohboi wrote:Interesting graph and speculations (though I'm not sure the former supports the latter as much as you imply).

I somehow missed that this was a discussion about when ag could have arisen. Probably the main limiting factor for it developing during "5E" was that human language probably had not yet developed into its fully nuanced modern form yet, humans could not have communicated and coordinated in a way to pass on all the requisite knowledge. On the other hand, fairly sophisticated stone tool technologies did get passed down in this and earlier periods, so who knows?

On your claim about the tropics, why do you think that ag (in the sense of fairly extensive fields of monoculture, not just gardens/horticulture) did not develop first in the tropics of sub-Saharan Africa?

The presence of elephants ,rhinos, lions, leopards wildebeests, zebras, warthogs, baboons,and giraffes among others would be my guess. Imagine trying to keep them out of your growing crops. Much easier in a grassland where you have already hunted the big grazers and predators down to a level of scarcity and the wild wheat and barley comes up by itself.
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Re: Abrupt Climate Change

Unread postby Synapsid » Sun 08 Jan 2017, 16:36:38

Tanada,

What evidence is there that modern humans crossed the Straits of Gibraltar from Africa to Europe during 3C? This is new to me.
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Re: Abrupt Climate Change

Unread postby Tanada » Mon 09 Jan 2017, 04:45:39

dohboi wrote:Interesting graph and speculations (though I'm not sure the former supports the latter as much as you imply).

I somehow missed that this was a discussion about when ag could have arisen. Probably the main limiting factor for it developing during "5E" was that human language probably had not yet developed into its fully nuanced modern form yet, humans could not have communicated and coordinated in a way to pass on all the requisite knowledge. On the other hand, fairly sophisticated stone tool technologies did get passed down in this and earlier periods, so who knows?

On your claim about the tropics, why do you think that ag (in the sense of fairly extensive fields of monoculture, not just gardens/horticulture) did not develop first in the tropics of sub-Saharan Africa?



You missed it because I was answering Onlookers belief that we have been 'in a stable climate' which is frequently stated all over the place was the prerequisite for the development of agriculture which permitted concentration of population in villages to specialize, grow into cities and eventually develop the Industrial Revolution. To wit,

onlooker wrote:We were in a relatively stable climatic period until the Industrial revolution and the spewing of so much CO2. So yes the history of Earth has been punctuated by abrupt climate changes but usually they have had some underlying reason. In this case the underlying reason is US. And no the Sun is not particularly potent in fact it is according to some scientists currently in a less luminescent period.


As you yourself admit symbolic language is not a prerequisite for passing knowledge from one generation down to the next. Even more than that we have no reason to conclude symbolic language was not part of our species from the very beginning and we have lots of artifacts like carved statuettes and bone flutes dating back to before the Toba eruption in South Africa and a few other places. Art and music are symbolic language of their own sort, if you can understand a figurine represents a person of a god/goddess then you are using symbolic language.

As for why agriculture developed first in the river valleys of the temperate zones instead of the tropics that one is easy. In the tropics wild foods grow abundantly and wild animals are plentiful because the year around weather promotes growth of plants and support a large diverse population of animals. In the temperate zones our ancestors moved to during the last ice age things were not terribly different though they did experience winter effects when less food was present. Then at the end of the last glacial maximum when the ice sheets started collapsing what had been temperate mixed forest land converted into desert. Many rivers dried up completely and in other places plant life retreated to the river valleys drawing the stone age hunter gatherers along with the plants to where the food still was. Someone figured out if they planted the seeds of the plants they used for food and got rid of the shoots of the plants they did not eat they would have more food and agriculture was born.

In the tropics the swing in and out of major glaciations doesn't have anything like that level of impact on the plant communities used by the hunter gatherer cultures, so there was no huge incentive to develop agriculture and do all that work of saving seeds and planting and weeding and tending before harvesting. Why do all that work when the 'nature gods' already had it covered and all you had to do was cycle around your territory gathering as you went?
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Re: Abrupt Climate Change

Unread postby kiwichick » Mon 09 Jan 2017, 05:22:14

thanks for that T .....sounds like reasonable explanation for the evolution of agriculture
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Re: Abrupt Climate Change

Unread postby onlooker » Mon 09 Jan 2017, 05:51:43

Yes thanks T for that. Showing the mutability of the climate system over even relatively short geologic time periods. Fact is even in H.S. I remember hearing this meme about how stable our climate has been the last ten thousand years or so. Was wondering how the scientific community now views this and if the HS and college textbooks have been updated. I ask also because the science of abrupt climate change seems only recently to have become so popular. Also Cid made a reference to how are scientists only now seem to be conceding how frequently , how dramatically and how extreme these changes can be
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Re: Abrupt Climate Change

Unread postby dohboi » Mon 09 Jan 2017, 08:07:39

Yes, thanks T.

Note that I was speaking fairly specifically about not just 'symbolic language' in general, but modern human language, with the wide range of phonological, lexical, and syntactic range seen in all known languages studied. Last I looked, it wasn't till about 100,000 years ago that humans evolved the requisite peculiar anatomy to enable at least the first of these (non-obligate nose breathing, pharyngeal cavity...). But I'm not necessarily up on all the latest research here.

But yes, there must have been some still very elaborate systems of communication and expression before this evolved.

By the way, have you heard of the book "Why Big Fierce Animals Are Rare" ? You might find it interesting.

https://www.amazon.com/Why-Big-Fierce-A ... 0691023646
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Re: Abrupt Climate Change

Unread postby Tanada » Mon 09 Jan 2017, 10:27:19

I should have posted this yesterday but I have been very ill and my brain is a bit fuzzy atm. You should all read this link from NOAA about the short cycle events I was referring to when I posted that graph of the major glaciation cycles.

https://www.ncdc.noaa.gov/paleo/abrupt/data3.html

Dansgaard-Oeschger events happen every thousand to three thousand years on average, Heinrich events happen every 10,000 years. When they line up to reinforce each other you can get quite an abrupt shift in whatever the current state of the climate is, sometimes they will cause a long decline to pause or reverse direction for a period, other times they will cause it to drop much faster than the average for a period.

There is a tendency for human being to look for the 'key stone' factor in every pattern we find in nature. Focusing on just the sun, or just CO2, or just Methane... The truth is there are innumerable factors all forcing things in different directions and when a forcing in a direction lines up TaDa Abrupt Change occurs!

The more scientists learn and publish about climate the more of these wiggle and gyrations they find and the elusive keystone factor continues to retreat. What makes putting so much CO2 out there risky is the Earth has three known relatively stable conditions. In the paleo climate record we know the Earth likes to hold an average temperature of 22C at the top end or a frigid 12C at the bottom end. Under strong forcing these numbers can be pushed up or down a couple degrees C but at no time since the origin of life and the development of the carbon cycle have we greatly exceeded these two values. The other thing we know from the record is there is a halfway climate state that is also relatively stable that cycles around 17C.

When the average temperature of the whole earth is 12-10C then major to massive glaciation takes place, at the very coldest nearly the entire ocean surface has ice on it. So much water is in continental glaciers that the entire continental shelf is laid bare and sea level is around 650 feet aka 200 meters.

At 21-23C on the other end of the spectrum the earth is truly a hothouse with semi-tropical conditions prevailing as far as 65 degrees north and south of the equator and temperate conditions extending all the way to the geographic poles. Under these conditions all of the water on the planet is found as liquid or water vapor with the possible exception of high mountains near the poles where snow might persist.

At 17C where the Earth wavered around from 34,000,000 ybp until about 3,000,000 the Earth was divided by hemispheric weather patterns. The Northern Hemisphere was semi-tropical to at least 63 degrees north, we find palm tree pollen and other fossil evidence of that ecosystem in Greenland, the Canadian Arctic Archepelligo, Alaska and Siberia and finally Scandinavia. At the same time the island of Greenland was nearly ice free outside of the mountains and there were Hippopotami wading in the Thames river near the current location of London, England. At the exact same time Antarctica still had a very large ice sheet, but it now appears all the ice shelves around the periphery were melted away and much of what we call the West Antarctic Ice Sheet was also absent which all put world sea levels circa 12-25 meters above today's levels depending on whose estimates you believe are most reliable. Part of the problem is erosion from the ice sheets over the last 3,000,000 years in the north has greatly changed the landscape. It is likely that the Great Lakes and Hudson's Bay in North America did not exist as such, and that the island of great Britain wasn't an island at all, but part of a plain where the mountains of Scotland and Wales were a kind of continental chain loosely connecting up into Scandinavia. The great Ice Sheets pushing out from the higher mountains in Scandinavia and the mountains on Baffin Island scraped away hundreds of feet of material and pushed it south. Its appears from some of the literature that the North Sea was a vast fertile plain before the ice age struck the north. Even more confounding is the isostatic rebound effect, all that two miles of ice on the continents weighed a heck of a lot and land everywhere they stood is still rising. IIRC the world record currently is in the western edge of Hudson's Bay where the land is still rising by about a centimeter a year outpacing sea level rise and actually getting higher above sea level. Another confounding variable is the gravimetric pull of the ice sheets working against the centripetal force of the earths rotation. The gravity field warping effects of the ice sheets pull water towards the poles while the centripetal angular momentum of the rotation pulls the water towards the equator. When more ice is at the poles they exert more gravitational pull and shift more ocean water towards the poles. When there is less the opposite happens and more water accumulates around the equator. As a bonus effect when more water is attracted in either direction it adds too the gravitational effect making it even stronger than a first order approximation.

When we lose the Greenland ice sheet, which I now believe is unavoidable, the sea level in the north Atlantic may actually go down from the gravitational effect dissipating more than the additional volume of water would add. There are scientists who believe absent the ice sheet the coast of Greenland, Labrador, northern Newfoundland, Iceland and Scotland may actually go down as much as a meter. But all that water relaxing away from Greenland is still going somewhere and the where is the equator and a lessor and lessor effect south of the equator.

On the other hand if Antarctica loses the entire Western Ice Shelf that is almost as much water as Greenland, and in that case the magnifying effect will be the equator and lessor and lessor north of the equator.

In this fashion Greenland probably adds enough to Antarctica to keep sea level there relatively stable if Antarctica also loses the WAIS keeping levels stable in the north Atlantic. Either way the people who get the double whammy are the equatorial coastal folks, the Amazon and Congo rivers both enter the Atlantic from very near the equator. That means their river deltas will be swamped and the sea level rise will go much further inland into both the Amazon and Congo basins. In the Indian Ocean the effect will be bad for Zanzibar and the Persian Gulf and the major rivers of India, Pakistan and Bangladesh. Further around the equator Indonesia is literally straddling the equator. Some of the smaller island may disappear completely and coastal populations in some of the most densely packed real estate on the planet, Java Island, will be forced to relocate to higher ground. On into the Pacific the Philippines will be hit hard, they have a lot of mountains inland but the bulk of the population currently lives in the coastal plains. Some of the atoll islands in the mid pacific like Wake and Midway will be swamped out of existence and return to being just coral reefs, and folks in Hawaii and French Polynesia will have to move up higher just like the Indonesians and Philippine citizens.

All in all the Tropics lose and the Northern Hemisphere gains from the exchange of our prior world average 12 C climate for the 17 C climate we are currently on course for. Growing seasons in Scandinavia and the Taiga zone that wrap around the planet between 55 and 70 degrees north will be quadrupled or more in length. Alaska and Sweden already grow world record holding Cabbages because of their extreme daylight periods in summer. Picture that effect with all crops because warmer means they can plant rice and beans and maize as well as the lettuce and cabbage they grow so well now.
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Re: Abrupt Climate Change

Unread postby Tanada » Mon 09 Jan 2017, 10:54:18

Synapsid wrote:Tanada,

What evidence is there that modern humans crossed the Straits of Gibraltar from Africa to Europe during 3C? This is new to me.


The evidence is in the timing of the cave art fins in Spain and Portugal plus the tools and skeleton remains that come from the Homo Sapiens vs the Neanderthal lineages. There are three proposed routes for Sapiens reaching Spain/Portugal, directly via the Strait of Gibraltar, mid sea by crossing from Tunisia to Malta/Sicily/Italy and also by dispersal from the Middle east up into the Black Sea/Danube River valley.

Currently you can find Archeologists in each of the camps claiming their data proves they are right and the others are wrong. Numbers for Spain/Portugal range from as early as 45,000 ybp by advocates to as late as 18,000 ybp by doubters.

Département d'Anthropologie, Université de Montréal wrote:The dispersal of modern humans into Eurasia and the extinction of Neanderthals during the last glacial period coincide with a pronounced period of climate instability. Prior to this, anatomically modern humans and Neanderthals produced very similar archaeological signatures and probably led very similar lives. By 45,000 years ago, however, modern human populations had adopted an Upper Palaeolithic culture characterized by the exchange of symbolic items of material culture within spatially extensive social networks and were dispersing across Eurasia. Several interesting questions arise from these observations, the most important of which concerns the role played by climate change in the development of modern human culture, the dispersal of modern human populations and the extinction of the Neanderthals (d'Errico and Sánchez Goñi 2003; Gamble et al. 2004; Müller et al. 2011; van Andel 2003). Our research will address these questions using the archaeological record and high-resolution climate simulations covering the last glacial period in Europe. The specific timeframe of interest begins 60,000 years ago with Marine Isotope Stage 3 (MIS 3) and finishes at the end of the Last Glacial Maximum (LGM), 19,000 years ago. Climate conditions directly and indirectly affect the spatial distribution and mobility of prehistoric populations; mobility patterns, in turn, are intrinsically linked to patterns of social organisation and the production of material culture (Delagnes and Meignen 2006; Delagnes and Rendu 2011; Kuhn 1995). Thus, climate change is a potentially significant factor to consider when studying the cultural dynamics of prehistoric people.

With few exceptions (Banks et al. 2013) archaeologists have used climate simulations at relatively coarse spatial (>100 km2) and temporal resolution to investigate the impact of climate change on prehistoric populations (Davies and Gollop 2003; Gamble et al. 2004; van Andel 2003). Climate change and climate variability have yet to be thoroughly investigated at finer spatial and temporal scales, however. The amplitude of climate change and the degree of variability required to affect social networks and stimulate dispersal are not yet established, therefore, nor do we fully understand how humans and Neanderthals may have differed in their response to environmental change at different scales. Our research programme aims to correct this situation by using high-resolution climate simulations (14 km2) which we have developed for this purpose to create detailed, dynamic spatial models of the geographic distribution of modern human and Neanderthal populations in Western Europe during the last glacial period. These models will allow us to track the responses of Neanderthal and modern human populations to environmental change at a critical period in their biological and cultural evolution (MIS3 to the LGM). We will also use these models to evaluate the relative importance of two hypothetical dispersal routes for modern humans entering Western Europe: 1) the Middle Danube and the Rhône valley corridor; 2) the Mediterranean route, which connects coastal Italy (Liguria) to France and the Iberian Peninsula. Finally, the predictive power of the spatial models we produce will be harnessed to design archaeological field surveys along the proposed dispersal routes. The results of this research programme will help fill significant gaps in our understanding of the fate of Neanderthals and the history of human colonisation of Europe as well as contributing to a better understanding of the range of reactions human societies display in the face of climate change with implications for the future.


Of the 11 subterranean sites the team studied along northern Spain's Cantabrian Sea coast, the cave called El Castillo had the oldest paintings—the oldest being a simple red disk.

At more than 40,800 years old, "this is currently Europe's oldest dated art by at least 4,000 years," said the study's lead author Alistair Pike, an archaeologist at the University of Bristol in the U.K.

If the new dates are correct, they also could make the El Castillo art the oldest known well-dated cave paintings in the world—a title previously held by France's Chauvet cave paintings, believed to be at least 37,000 years old.

Pike's team teased out the new dates using a method that relies on known rates of decay in uranium—specifically uranium in calcium deposits that had formed over the paint. The mineral-based paint itself couldn't be dated, because it contains neither uranium nor the carbon needed for radiocarbon dating.


The first Homo sapiens (Grimaldi man) arrived by small groups in northern Spain around 45,000 - 35,000 BP. They cohabited for a time with the last of the Neanderthals, and then developed a significant culture known as paleolithic cave art which developed across Europe, from the Urals to the Iberian Peninusula, from 35,000 to 11,000 BC. Because of their deep galleries, isolated from external climatic influences, these caves are particularly well preserved. The caves are inscribed as masterpieces of creative genius and as the humanity’s earliest accomplished art.

The last Ice Age then began to make its influence felt, ending in around 18,000 BP. During this period cave art developed in the eastern part of Cantabria, producing an individual style (Altamira, La Peña del Candamo, El Castillo, Las Pasiega, El Pendo, La Garma, Chufin and El Pendo).

The artistic apogee, known as Magdalenian, corresponds to the end of the Ice Age, from 17,000 to 13,000 BP. This was the period of the major works in the decorated caves, with a great variety of motifs and techniques of representation. This was one of the key moments of the history of art, as seen for example in the polychrome figures of Altamira and El Castillo, the combination of engraving and painting, the use of the rock forms themselves, and realistic detail in the animal figures in most of the nominated caves.

From 13,000 to 10,000 BP, the climate became warmer (Holocene), causing a profound transformation in human lifestyles, together with a decline in cave art. Las Monedas is an example of late cave art, and there is no evidence of cave art later than 11,000 BP.
I should be able to change a diaper, plan an invasion, butcher a hog, design a building, write, balance accounts, build a wall, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, pitch manure, program a computer, cook, fight efficiently, die gallantly. Specialization is for insects.
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Re: Abrupt Climate Change

Unread postby onlooker » Mon 09 Jan 2017, 11:57:50

A 2009 study in the journal Science found the last time in Earth’s history when CO2 levels in the atmosphere were this high for a sustained period was between 15 and 20 million years ago.

Then, according to the study, temperatures were between 3C and 6C warmer than today. Ice sheets, the study said, had melted to the point where sea levels rose between 25 and 40 metres.

https://www.theguardian.com/environment ... ts-history
This high referring to the 400 ppm. So, how do you assess this Tanada? How certain and how fast could we be headed for 3C to 6C above current temperature.? It seems from your post that humans could do fairly well in the Northern latitude regions and nothing like an extinction process. I am simply curious given these relatively high levels of CO2. I am veering from the Cid and Guy scenarios of extinction or near extinction happening very soon within this century. If this temperature increase does not happen too fast it would give us time to adapt.
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Re: Abrupt Climate Change

Unread postby KaiserJeep » Mon 09 Jan 2017, 13:58:14

The entirely spectacular Chauvet-Pont-d'Arc cave art in Southern France has been radiocarbon dated to the period 45,000 BP to 28,000 BP, with two distinguishable periods of cave occupancy. Nobody can tell with any certainty whether it was early Homo Sapiens Sapiens or late Homo Neanderthalensis which made these paintings, as they were created when both species were present in Europe.

I believe that popular theory says that modern humans made all cave art. Neanderthal sites show evidence of fire, bone and wood and stone tools, but no representational art has ever been found at any of literally hundreds of such sites. The two species share 99.7% of their DNA (including common Homo sapiens ssp. Denisova DNA) but were very different in appearance and apparent culture.

Time to plug one of my favorite documentaries. A wonderful work by Werner Herzog called Cave of Forgotten Dreams.
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Whenever I get depressed I watch it again. These were undeniably people no matter what their species classification. They successfully dealt with climate change on a massive scale and they did so without Science, Agriculture, Medicine, or the Internet. They may or may not have had religion - one theory being that the above cave figures which show fifteen distinct animal species are the evidence of an religion based upon animalism.

Had they simply created images of themselves, we might have an answer to what human species they were. However, deep in the cave on a limestone pillar there is what is believed to be a fertility symbol called the "Venus", comprised of a vulva, partial legs, a torso and the head of a bison - causing some to say it should be named the "Minotaur". No other human figures are present, we don't really know if the Venus is religious art or teenaged graffiti from 37,000 BP.

They survived and they became us. We can survive as well.
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Re: Abrupt Climate Change

Unread postby Tanada » Mon 09 Jan 2017, 14:29:12

onlooker wrote:
A 2009 study in the journal Science found the last time in Earth’s history when CO2 levels in the atmosphere were this high for a sustained period was between 15 and 20 million years ago.

Then, according to the study, temperatures were between 3C and 6C warmer than today. Ice sheets, the study said, had melted to the point where sea levels rose between 25 and 40 metres.

https://www.theguardian.com/environment ... ts-history
This high referring to the 400 ppm. So, how do you assess this Tanada? How certain and how fast could we be headed for 3C to 6C above current temperature.? It seems from your post that humans could do fairly well in the Northern latitude regions and nothing like an extinction process. I am simply curious given these relatively high levels of CO2. I am veering from the Cid and Guy scenarios of extinction or near extinction happening very soon within this century. If this temperature increase does not happen too fast it would give us time to adapt.



The problem with this study is the same problem I have with most of them. They treat the Earth as a single unified hemisphere when we know with absolute certainty that the North was tropical for tens of millions of years when the South was in the grips of the ice age. There is a 30 Million year discrepancy between when the South cycled from Hothouse to Icehouse before the North followed suite. Clearly the Earth is not one unified climate where a 3-6C GLOBAL average change is the same as a 3-6C ARCTIC average temperature change. This fact is not in dispute. Nobody denies that Antarctica became a partially glaciated continent circa 34 MILLION years ago and Greenland only became glaciated around 3 MILLION years ago. A 3C GLOBAL average temperature increase would put us back into that 17 C period of world climate where the North is fully deglaciated and the south (Antarctica) is still mostly glaciated.

What I see happening is the North flipping back into the hothouse climate 'soon' geologically speaking. Could be today, could be 1000 years but either way that is 'soon' compared to the 3 Million years of ice ages in the north. The consequences of this shift will be a rapid scrambling (Abrupt Climate Change) of weather patterns potentially disrupting food crop production to the degree that it causes mass famine events as the USA/Ukraine/Russia lack the surplus grain to export and need to import from Australia/South Africa/Argentina in competition with countries like India and China that are already major food importing nations. Once the weather patterns resume some type of stability crops will be planted to fit the new conditions and things will go on from there.

The gap between where we can flip the climate of the North into hothouse (above 400 ppmv CO2) and where we can flip the southern hemisphere into hothouse (around 780 ppmv CO2) is not a small change and will not happen rapidly pretty much no matter what we do. Right now we are burning fossil fuels fast enough to build atmospheric loading 2 to 3 ppmv a year. Say all the carbon sinks stop working and we start building CO2 accumulation at 5 ppmv per year. To get from 400 to 780 at 5 per year is 780-400=380; 380/5=76 years. Will we really be burning fossil fuels at maximum rates we can manage for another 76 years? Holy crud I hope not! And so long as those sinks continue working somewhat we are not building at 5 ppmv so the time interval is longer than 76 years.

I presume one of several paths will be followed, the first path is we burn just as hard as today until the climate in the north flips, then we go "Oh CRUD!" and get off of fossil fuels as quickly as we possibly can. Path two we burn as fast as we can until the northern climate flips, we get a couple bad years of drought/flood/whatever but because of our ability to use power equipment, irrigation, artificial fertilizer and whatnot we manage to not have a famine disaster. At that point people shrug, say its kind of nice not having heating bills in Detroit in the winter and things go on slowly changing as alternatives to fossil fuel improve and supplies of fossil fuels get to be in short supply. Path Three we do as before, world wide famine ensues a billion or more people literally starve to death, India and China and Pakistan demand food or they will use their nuclear weapons to get what they need, World War II ensues and civilization drops back to about 1880 levels in places outside the major fallout zones. Nuclear winter cools things off for 2 to 3 years but not enough to drop us back into the ice age climate because the CO2 stays in the air and the dust and smoke particles do not. The billion to 3 billion survivors shrug and get on with the job of living even if they lament the loss of the 21st century technology they used to have access to easily. Despite predictions to the contrary we do not all die and the technology level of 1850 ish coupled with the knowledge of fertilizers and rotating crops and so on and so forth let the survivors support 2-3 Billion by the end of the first century after the global thermonuclear war. There are simply way to many physical copies of books about how people like Newcommen built his first steam engine in the 1700's for all the knowledge to be lost, and there is still a heck of a lot of coal left in easily accessible seams in the ground for the survivors to exploit once they have enough food to eat. Knowledge doesn't stay static, you only need one town with a steam hobbyist to survive and they will be able to turn out more steam engines in very short order. Nothing like the super efficient turbines used at the big electrical plants mind you, but good enough to power a tractor and plow or harrow the fields and pull along the seeders and so on and so forth. One town on the whole planet is all it takes, and that town will have a surplus of food compared to the towns using stoop labor, and that will drive other towns to follow along with their own steam or whatever technology they manage to keep. Its not like Henry Fords first gasoline/alcohol tractor was a high technology item unless you are looking at it with 1920 eyes. Or the British kerosene fueled hot bulb engine tractors, or the more complex German primitive Diesel tractors. All of them were appearing on the market in the roaring 20's when having a telephone was all the rage and a crystal radio set was high electronics technology.

IOW its a heck of a long distance between chipping your stone spear point and using your repaired lawn tractor to plow the neighbors garden, and with the number of suburban and rural homes with lawn tractors out there you can't possibly destroy all of them and the knowledge needed to get useful work out of them. There are too many books in too many places and too many people with too many skills to eliminate all of them. Even if you got 99 percent effective destruction that still leaves millions of technology bits and pieces and folks with knowledge scattered among the survivors. That is part of the reason books like The Road fall flat and TV shows about the Zombie Apocalypse are just fun and games. Say you killed off everyone in the USA except the residents of some tiny town in the mountains of the Idaho panhandle. Unless they are unusual that town will have a library with real paper books in it, and it will have retired old timers who know things and remember things from the mid 20th century. Many of those old timers will have kids or grand kids who heard stories or helped work on those pre computer devices and unless they are very unusual there will be carpenters and bricklayers and mechanics who work and live in even a very small town. The biggest work would be not having a doctor, but if they have a vet as most towns do they have a big leg up because a human is just another animal.
I should be able to change a diaper, plan an invasion, butcher a hog, design a building, write, balance accounts, build a wall, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, pitch manure, program a computer, cook, fight efficiently, die gallantly. Specialization is for insects.
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Re: Abrupt Climate Change

Unread postby onlooker » Mon 09 Jan 2017, 14:38:53

Thanks T, for that very lucid and informative post as usual. Oh and hope you recover quickly from your malady.
" Courage is resistance to fear, mastery of fear, not absence of fear."
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Re: Abrupt Climate Change

Unread postby Tanada » Mon 09 Jan 2017, 14:43:34

onlooker wrote:Thanks T, for that very lucid and informative post as usual. Oh and hope you recover quickly from your malady.


I broke a tooth December 22 and my dentist was on vacation so I made it through the holidays with handfuls of aspirin. When I got in to see him last week the tooth had developed an serious infection so now I am on heavy anti-biotics because before he can determine the best course of action the infection has to be gotten rid of. Meanwhile with all the family events I managed to catch a nasty cold bug. I highly recommend you avoid sneezing or coughing with a broken tooth, it can be quite unpleasant.
I should be able to change a diaper, plan an invasion, butcher a hog, design a building, write, balance accounts, build a wall, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, pitch manure, program a computer, cook, fight efficiently, die gallantly. Specialization is for insects.
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Re: Abrupt Climate Change

Unread postby kiwichick » Mon 09 Jan 2017, 15:02:06

thanks T....keep swallowing that Vit. C............
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Re: Abrupt Climate Change

Unread postby KaiserJeep » Mon 09 Jan 2017, 15:02:27

Sorry about your tooth, T - been there, done that, and Xodol is your friend. It is a potent combination of 300 mg acetaminophen and 5 mg hydrocodone. My doctor has trusted me with 50 tablets annually and I use them mainly for skeletal pain, I am in my 37th year after being diagnosed with severe osteoarthritis. Whenever I over-exert myself I can't sleep without them due to pain.

I also share your opinion that the knowledge we have cannot be lost, ever. I even go further and say that our information network will survive as well, with full access to knowledge for all. It's just too useful to abandon.
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Resistance is Futile, YOU will be Assimilated.

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Re: Abrupt Climate Change

Unread postby kiwichick » Mon 09 Jan 2017, 15:04:17

I put this in the Oceans thread.....but maybe it should be here too............

http://climatenewsnetwork.net/antarctic ... 9-38798465
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