The long article below discusses in detail the data showing a weakening of the Gulf Stream function over the last century (maybe two centuries). The Gulf Stream moves hot water from the Equator north to northwestern Europe, such that average temperatures there in the winter are as much as 40 degrees warmer than at the same latitude in Canada. The weakening seems to happen when volumes of fresh water, less dense than salt water, fail to sink even after cooling, halting the flow caused when warm Gulf Stream waters cool and sink off Europe and then wander south deep in the ocean. There is a worldwide current flow as well, taking about 1,000 years for a full cycle. A warming Arctic has melted volumes of sea ice and Greenland glacier ice and this less dense fresh water, not sinking as it should, seems to be slowing the Gulf Stream.
What happens if the Gulf Stream collapses, and the transfer of heat slows or stops? Waters get hotter around the Equator, and colder near the North Pole. Europe and North America and Asia will become colder; in the case of Europe, much colder. Entire weather patters will change in ways impossible to predict. The much colder conditions might even start off another ice age, because perhaps winter snows won’t melt year to year and over decades and centuries a huge ice sheet forms.
While it looks like the Gulf Stream may have been slowing even before the last half century of warming, especially near the North Pole, recent warming, allegedly caused by man’s industrial growth and CO2 emissions, may have ironically accelerated the melting of fresh water ice in the north such that the Gulf Stream slowdown, or even collapse, has been hastened, thereby hastening a return to cold conditions and even the next ice age.
If we go back to the last warm time before this one, the Eemian 120,000 years ago, which lasted about 10,000-15,000 years, we learn the earth was one or two degrees Centigrade warmer than today, arctic ice nearly all gone, and sea levels 10-20 feet higher. Maybe, back then, the melting of the Arctic and Greenland ice slowed the current and brought on the cold, and the ice. Maybe, in fact, the entire system of ice ages over the last two million years, at roughly 100,000 year intervals, happened the same way – the marine current systems shift and adjust such that warmer Equatorial waters are sent north to warm the north of Europe and start the melting of the ice, until the great ice sheets are gone, ushering in a relatively warmer and stable time when temperatures are more stable and warmer, until the warmth itself sends enough fresh water into the northern ocean to slow the current and bring back the cold. And then, once the cold is established, again and again during the ice age there are fits and starts to recreate that warmer flow, resulting in the documented frequent warmings and coolings, still all colder than during an interglacial, until, finally, one takes “hold” and a 10-20,000 year interglacial emerges.
The Younger Dryas, a period lasting 1,000 years shortly after the end of the last ice age, might have been caused when a great glacial flood burst into the Atlantic and slowed or stopped the Gulf Stream, bringing back cold conditions for ten centuries. Maybe this flood was the great flood that drained a huge lake south of Hudson’s Bay. That flood hit the sea at around 40 degrees north, well south of the latitiude of the Greenland glaciers. Maybe the cold time was shorter because at that latitude the warmth of the ocean and the Gulf Stream handled the less dense fresh water better than a thousand miles to the north.
It is interesting that while the current alarm about climate change is the cooking of the earth, it may well be that it is precisely this “cooking” that triggers the next cold time, or ice age, by sending all that Greenland fresh water into the fast cooling Gulf Stream south of Iceland.
We, or our grandchildren, or theirs, are going to find out.
Posted in Real or Folk Tale? and tagged climate change, global warming, Gulf Stream, ice age, weather, Younger Dryas by Charles Sheldon with no comments yet.
First of all they aren’t talking about bringing BACK the mammoth but creating an elephant-mammoth hybrid with long hair and a lot of fat. To live where? Second, lower in the article is the statement that mammoths pushing away snow to get at the grass beneath exposes the soil so the permnafrost can stay frozen. Really? Seriously?
Scientists Say They Could Bring Back Woolly Mammoths. But Maybe They Shouldn’t
Updated September 15, 20216:24 AM ET
An artist’s impression of a woolly mammoth in a snow-covered environment. Leonello Calvetti/Stocktrek Images/Getty Images/Stocktrek Images
Using recovered DNA to “genetically resurrect” an extinct species — the central idea behind the Jurassic Park films — may be moving closer to reality with the creation this week of a new company that aims to bring back woolly mammoths thousands of years after the last of the giants disappeared from the Arctic tundra.
Flush with a $15 million infusion of funding, Harvard University genetics professor George Church, known for his pioneering work in genome sequencing and gene splicing, hopes the company can usher in an era when mammoths “walk the Arctic tundra again.” He and other researchers also hope that a revived species can play a role in combating climate change.
“We are working towards bringing back species who left an ecological void as they went extinct,” the company, Colossal, said in answer to questions emailed by NPR. “As Colossal actively pursues the conservation and preservation of endangered species, we are identifying species that can be given a new set of tools from their extinct relatives to survive in new environments that desperately need them.”
To be sure, what’s being proposed is actually a hybrid created using a gene-editing tool known as CRISPR-Cas9 to splice bits of DNA recovered from frozen mammoth specimens into that of an Asian elephant, the mammoth’s closest living relative. The resulting animal — known as a “mammophant” — would look, and presumably behave, much like a woolly mammoth.
Some say reintroduced mammoths could help reverse climate change
Church and others believe that resurrecting the mammoth would plug a hole in the ecosystem left by their decline about 10,000 years ago (although some isolated populations are thought to have remained in Siberia until about 1,700 B.C.). The largest mammoths stood more than 10 feet at the shoulder and are believed to have weighed as much as 15 tons.
Mammoths once scraped away layers of snow so that cold air could reach the soil and maintain the permafrost. After they disappeared, the accumulated snow, with its insulating properties, meant the permafrost began to warm, releasing greenhouse gases, Church and others contend. They argue that returning mammoths — or at least hybrids that would fill the same ecological niche — to the Arctic could reverse that trend.
“With the reintroduction of the woolly mammoth … we believe our work will restore this degraded ecosystem to a richer one, similar to the tundra that existed as recently as 10,000 years ago,” the company says.
Love Dalén, a professor in evolutionary genetics at the Stockholm-based Centre for Palaeogenetics, is skeptical of that claim.
“I personally do not think that this will have any impact, any measurable impact, on the rate of climate change in the future, even if it were to succeed,” he tells NPR. “There is virtually no evidence in support of the hypothesis that trampling of a very large number of mammoths would have any impact on climate change, and it could equally well, in my view, have a negative effect on temperatures.”
The body of Lyuba, a baby woolly mammoth who lived about 42,000 years ago on the Yamal Peninsula of Siberia, is exhibited in Hong Kong. South China Morning Post/South China Morning Post via Getty Images
The techniques might be better used to help endangered species
But even if the researchers at Colossal can bring back mammoths — and that is not certain — the obvious question is, should they?
“I can see some reasons to do the first steps where you are tinkering with cell lines and editing the genomes,” Dalén says. “I think there is a lot of technological development that can be done [and] we can learn a lot about how to edit genomes, and that could be really useful for endangered species today.”
Joseph Frederickson, a vertebrate paleontologist and director of the Weis Earth Science Museum in Menasha, Wis., was inspired as a child by the original Jurassic Park movie. But even he thinks that the more important goal should be preventing extinction rather than reversing it.
“If you can create a mammoth or at least an elephant that looks like a good copy of a mammoth that could survive in Siberia, you could do quite a bit for the white rhino or the giant panda,” he tells NPR.
Especially for animals that have “dwindling genetic diversity,” Frederickson says, adding older genes from the fossil record or entirely new genes could increase the health of those populations.
Speaking with NPR in 2015, Beth Shapiro, a paleogeneticist at the University of California, Santa Cruz and author of How to Clone a Mammoth: The Science of De-Extinction,said emphatically, “I don’t want to see mammoths come back.”
“It’s never going to be possible to create a species that is 100% identical,” she said. “But what if we could use this technology not to bring back mammoths but to save elephants?”
Mammoths might upset existing ecosystems
Colossal’s expressed aim also brings up another ethical concern: Although the extinction of the mammoth thousands of years ago left a gap in the ecosystem, that ecosystem has presumably now adapted, at least imperfectly, to their absence.
“There is a new normal that has existed for thousands of years that has adapted to the continually changing climate,” Frederickson says. “Bringing back something that has all the characteristics that would have thrived in the Pleistocene doesn’t necessarily mean it’s going to survive today, especially when you’re mixing in the unknowns of other genes that are acting in a warm-weather tropical animal and then trying to move it to a new environment.”
“There were plants and animals that were living alongside the mammoth that are now long gone or have drastically shrunk in their range, and just bringing back the mammoth won’t bring those back,” he says.
Colossal says it’s not trying to bring back an invasive species but instead wants to “enrich an ecosystem that has been, and continues to be, steadily degrading without its presence.”
In yet a different sense, there’s the question of how mammoths might fit in.
“The proposed ‘de-extinction’ of mammoths raises a massive ethical issue. The mammoth was not simply a set of genes — it was a social animal, as is the modern Asian elephant,” Matthew Cobb, a professor of zoology at the University of Manchester, told The Guardian, in 2017. “What will happen when the elephant-mammoth hybrid is born? How will it be greeted by elephants?”
Predicted six-year timeline would be exceptionally short
All of this, of course, assumes that producing a mammophant is even possible. Colossal says it hopes to produce an embryo in six years. But with an estimated 1.4 million individual genetic mutations separating the ancient creatures from Asian elephants, the task of gene splicing could prove a mammoth undertaking.
Perhaps an even bigger obstacle might be developing an artificial uterus for gestating the embryos. Even Church acknowledges that this might not be so easy. Among other things, the company plans to create “a pumping system for exchange of gas, nutrient and waste metabolites, and umbilical blood supply with the goal of carrying a woolly mammoth embryo to term in vitro.” Researchers have been working on just such a device, but technical hurdles remain.
“Is this going to happen anytime soon? The answer is absolutely not,” says Frederickson.
Dalén agrees that the six-year timeline is “exceptionally short.” “It seems pretty ambitious,” he says.
But Church and his colleagues aren’t alone in their ambition. The idea of mammoth de-extinction has been around for some time, and other groups, such as the California-based nonprofit Revive & Restore, which last year managed the first-ever clone of an endangered species, the black-footed ferret, have also been working on a mammoth-elephant hybrid.
The traditional scientific view is that our ancestors hunted the mammoth to extinction, while more recent theories point to habitat destruction at the end of the last ice age as the biggest factor, but with humans still copping part of the blame.
Frederickson thinks that’s one of the reasons that the question of de-extinction — fueled by pop culture and real-world advances in science — is raised so frequently by
the patrons at the museum he heads. “I think, as humans, we have a little bit of guilt in us, still knowing that we almost certainly contributed to that extinction event.”
“This may be a way of getting that burden off of our backs,” he says.
Posted in Real or Folk Tale? and tagged arrogance, climate change, humility, ice age, mammoth by Charles Sheldon with no comments yet.
Humans arose during the last two million years, according to available fossil evidence, with so-called “modern humans” – that is, humans leaving behind evidence of culture, art, technology – emerging perhaps as recently as 70,000 years ago, or perhaps 200,000 years ago. Nobody is quite sure and a bitter argument is raging about the exact when and where, though nearly everyone agrees the first such “modern” people arose somewhere in Africa before migrating elsewhere.
This means that humans evolved coincident with the ice ages, that two million year period we call the Pleistocene within which ice has advanced and retreated on a roughly 100,000 year cycle, at least 20 times, with the most recent ice age having its “maximum” about 20,000 years ago before retreating until, maybe 12,000 years ago, the ice was mostly gone (except for some remaining caps in Canada and Eurasia). But, before that 20,000 year ago maximum, there were many rises and falls during the previous 80,000 years. It seems that even during the height of an ice age the summers could be hot, maybe as hot as today, just shorter, and of course the winters were colder. It also seems that the temperature could rise and fall over a very very short period, maybe as little as a year or two, certainly a decade. It seems likely that the way an ice age begins is not that somehow glaciers far in the north grow thicker and thicker and then march inexorably south to cover much of the land north of 40 degrees north; instead, a more likely cause is that the snows fail to melt one summer, then another, then another, until after 10 years the snow compresses to ice and after 100 years a thick glacier in place exists.
The earliest humans, as far as we know, did not farm, or grow crops. This invention, agriculture, started about 10,000 years ago, following the latest ice age, when a roughly 10,000 year period – the interglacial – began, when the weather stabilized for centuries of warmer weather. It may be, in fact I am sure it was, that humans during the ice time worked a form of “primitive” agriculture – using fire to clear underbrush so food plants could thrive, for example. The first human societies, whether modern or not, were hunter-gatherers, seeking game for meat and gathering nuts, fruits, edible plants, as well as foraging along the shore for shellfish and seafood, and of course fishing.
The ice age warm time between ice advances before the warm time we are now in occurred about 120,000 years ago. It was called the Eemian, and lasted 10,000 years. The average temperature during that interglacial was apparently warmer than even today’s warmer days, maybe as much as one or two degrees Celsius warmer, and the sea level back then was as much as 20-50 feet higher than the sea level is today. During the over 20 previous ice advances during the Pleistocene, land bridges appeared as sea levels dropped because of all the fresh water locked in ice. Sea levels dropped as much as 330 feet from sea levels today, and during the entire ice period, as the ice advanced and retreated, so did sea levels vary.
All of this serves to show that there were short periods of generally stable warm climate conditions called interglacials that lasted between 5,000 and 15,000 years (generally) with the warm period before the one we are now in – and approaching the end of according to the glacial record – happening over 100,000 years ago, maybe before the appearance of so called “modern” humans. This means that for most of human history, in fact for all of it, we lived and evolved during periods of great changes in climate, huge changes, some times happening within a year or two, and certainly within one or two lifetimes. These changes in temperature, weather, sea level, storm intensity all surely greatly influenced behavior patterns of prey animals and the location of edible plants. Along the seashore, the tide lines would rise, and fall, some times greatly, and all these changes would alter the locations and behavior of seafood clusters.
Of course, we humans have incredibly short memory spans. Who among us knows, for example, what our grandparents or great grandparents did every day to live? These days many people remember winters when the snow was much deeper, when they were children, though maybe that was because they were half their adult height. When I was a kid in the 1950s I remember vivid stories and memories of the Great Depression, seeing older men and women still carefully saving and pressing flat tin cans for reuse. Most people alive back then knew of times when electricity was scarce, even unavailable. A life without electricity today would seem unimaginable for most people alive in developed economies. Yet, a century ago, 1921, electricity was still not available for over half the U.S. population. The point here is that huge change is happening all the time these days and we forget about the change as time passes, and especially as those who lived in such different times pass on, because then instead of hearing directly from an eyewitness we hear from someone who was told by someone, and this must be the case for almost anything that happened more than 60 or 70 years ago. And, beyond that, say, back to the Civil War, the people alive then are now our great or great-great or even great-great-great grandparents, myths of imagination and memory.
So, even though during most of our history the climate has changed greatly and often, any changes occurring over, say, a century and surely over two or three centuries would not be seen in the immediate life of anyone living, not really, such that then there would be legends of warmer times, or colder times, almost myths, lost in the haze of memory and history. And this means that we humans think that what has been happening in our most recent memory – a year or several years – is what has and will always happen. We are, if nothing else, adaptive, and so we adapt, and as the climate changes, we adapt or die. We need to find new hunting grounds, or new edibles. We need to move the village because the sea now floods our shelter. The great herds upon which we depend have suddenly wandered away over newly exposed land that rose from the sea (though in fact the land emerged from the falling sea).
All of which to say, even though the climate has changed always (but changed much less during the warm times between glacial advances and retreats), within the lifetime of one person, much of the change, maybe all of it, would be impossible to see, and big changes over, say, four generations would soon be considered exaggeration or myth. What is true, though, is that the changes taking place force adaptation, learning, adjustment, flexibility, and this was surely the case everywhere on earth, even those places near the equator far from the advancing ice, because they, too, would be changing as well.
I think it was the ice ages that had much to do with making us human, maybe as much as the control of fire for the ability to build culture and learning with stories. These days many if not most among us think we face a climate crisis. What many if not most of us fail to realize is that the human condition is exactly one of adapting to climate crises, and it has always been so.
Posted in Origins and tagged adaptation, ancient humans, change, climate change, ice ages, memory, survival by Charles Sheldon with no comments yet.