The Evolutionary Game: How did Elephants survive the onslaught?

 

Another interactive lecture delivered by Meuianga (honorable) Mera Te Aì 'Enge'ite, chief scientific officer of the Reptilian Starfleet

Cadets, as you know, the evolutionary game, as you know, has many facets. So, there are many ways used by Earth’s creatures to cool down while making an effort. Let me make an example for you -- it will test your analysis skills. Let me show you this image of these two large animals on the screen.

You see two similar creatures of about the same size. As you already know from your training material about Earth, the one on the left is called “Elephant.” The ape scientists classify it as “Loxodonta Africana.” The other, on the right, is a wooly mammoth, also called mammuthus primigenius. You know that it is an extinct species today. You know that these animals existed (and the elephant still exists) together with the current dominant ape species, the naked ape called Homo Sapiens. There is clear evidence that the naked apes hunted both species using simple weapons, and it may well be that they hunted the mammoth to extinction. Instead, the Elephant survived, although nowadays he risks extinctions, too, because the apes have much better weapons. But let’s not get into that -- it is clear that the naked apes hunted mammoths with the same simple weapons they were using for hunting elephants not very long ago. The question for you, cadets, is how is it that elephants survived while the mammoths died out?

-- Ah… Meuianga. This is surely an interesting question.

-- Really. How that could be?

-- These two animals look very similar, indeed.

-- Of course, apart from one being furry, and the other not…. But it means only that one of the two lived in a colder climate, is that right?

Yes, cadets, the mammoth lived in a cold climate, in the Northern regions of the planet. That’s why it has that thick coat of fur. The Elephant, instead, lived, and still lives, in equatorial regions. It doesn’t need fur. But how would that affect their ability to escape being hunted by the Naked Apes?

-- Maybe it is what you told us before about the naked apes, Meuianga. The Elephant is naked.
-- Maybe it sweats? Just like the naked apes do?
-- That allows the elephant to cool down under effort? Is this the reason?

Not so simple, cadets. I can tell you that the elephant does not have a high density of sweat glands on its body. Nothing like the naked apes, which sweat all the time. Actually it has almost no sweat glands on most of its skin, except at the bottom of its feet. But those glands can hardly cool the body of the creature. They must be used mainly to mark the territory. As the elephant walks, it leaves a scent trail on its tracks. This is something interesting, too. Don’t you think so?

-- Indeed, Meuianga. Why should a creature leave a scent trail that’s easy for predators to follow?

-- Strange things happen on this strange planet. Naked apes and large beasts leaving a trail to make it easier for predators to hunt them.

Oh, cadets, you can’t imagine how many more strange things you still have to learn about this planet. And, yet, no matter how strange these things may be, never forget that for everything that exists in an ecosystem, on any planet of the galaxy, there has been a natural selection process that has led it to exist. And that’s true also for elephant feet leaving a trail of smell.

-- Well, Meuianga, I can imagine that it would make no difference for such a large beast to leave a trail of smell. It is so big that it couldn’t hide its trail anyway.

-- Yes, it seems reasonable. Yet, why make things easier for predators?

Cadets, think about this: what if the beast doesn’t have natural predators?

-- Oh… in that case it wouldn’t matter, of course, Meuianga.

-- You mean it is because it is so big?

-- Then, yes, we can see that most predators would have a hard time killing an elephant.

-- But didn’t you tell us that the naked apes hunt elephants? Then it has at least one predator.

Correct, cadet Lipotzoot'itan. Let me rephrase my sentence. What if the beast has just one natural predator? And you surely read in your training material that the naked apes have a very poor sense of smell….

-- Meuianga, you keep surprising us.

-- Indeed, amazing things you are telling us.

-- These elephants would not be worse off by leaving a smell trail for a predator that can’t follow it. Hence, natural selection did not select it out.

-- And so they probably use the scent to mark their territory.

Exactly, cadets. Exactly. But let’s go back to our initial question: why did Mammoths go extinct but not elephants? We don’t know if Mammoths had the same kind of sweat glands in the feet, but that couldn’t have had much to do with the fact that the naked apes exterminated them. So, there is something else to be considered here. Do you remember that I was telling you that elephants don’t have sweat glands on their bodies? If you think about that, it makes plenty of sense. With such a large body, the ratio of surface to volume is small, so sweat glands, if they had them, would only cool down the outer skin, but do very little to cool the whole beast.

-- Yes, Meuianga, we can see your point.

-- Sweating a lot would not be useful for such a large beast.

-- But then, how is that they managed to survive the hunting by the naked apes?

And you have the answer right in front of you. Look at the image. Look at it carefully. Don’t you see the difference? It is glaringly obvious.

-- Meuianga, maybe we are not good cadets

-- Maybe we are a little dumb.

-- They should kick us out of the Starfleet academy.

But, no, cadets, no! You are not dumb. You see, I have given this lecture to many classes of Starfleet cadets, and I can see how difficult it is for you to see something that it is so obvious once you notice it. You just need to learn. And for that you have to learn how to learn. It is for this reason that you are here. So, let me give you just a hint. A single word. Ears.

-- Ah….. the ears

-- Yes, the ears…. How couldn’t we notice the ears.

-- The elephant has such big ears! The mammoth has much smaller ones.

-- But what does it mean? How is it helping elephants to survive?

Excellent question, cadet Nätsyeaypxit'ite. The first step to answer a question is to frame it in the right way. How do those large ears help elephants to survive? And the answer is in a single word: vascularization.

-- Oh…. now we see it!

-- So obvious!

-- How could we have missed it!

Yes, you have it now, cadets. The large ears of the elephant are highly vascularized. A lot of blood goes through them, and so it cools down as the elephant moves. Actually, they flap their ears a lot to cool them down. Then, the blood goes into the elephant's body, and it cools it from the inside. Wonderfully efficient for a large animal! Actually, their whole skin is also vascularized, and it cools the body in the same way. If you observe their normal behavior, you see that they use their flexible nose, their trunk, to spray water over their bodies. Another way to cool down. But the large ears are the elephant’s radiators. They are their secret weapons against the naked apes and their wonderful sweating glands.

I see that you are awed, cadets, and correctly so. An ecosystem is such a complex thing that it is always amazing. Sometimes bewildering. Then, you can now notice another facet of the story. You see, the naked apes called “humans” evolved in a hot climate in the continent called Africa. The same place where elephants lived. So, naked apes and elephants co-evolved. It was one of those cases called “arms races.” The two species evolved together, both improving their metabolic efficiency. And not just that, also their social skills, but we’ll see that later. In any case, the naked apes couldn’t hunt down elephants by wearing them down, and so the elephant survived. Then, when the apes moved northward, they encountered another similar species, the mammoths. Unfortunately for the mammoths, they had never encountered those hunting apes, and they didn’t have the time to evolve an efficient cooling system. And so they were exterminated in a relatively short time, perhaps just a few tens of thousands of years. See? Everything clicks together! Evolution is a fascinating game, although also a cruel one. Those who lose the game, must die. It is the same everywhere in the universe.

-- Indeed, Meuianga

-- We are truly amazed…. Actually awed

-- Even bewildered. That may be a better way of saying it.

-- But, Meuianga, how about us, the reptilians? How do we compare with these creatures from Earth?

Oh…. that’s another facet of the story, cadet Runga'itan. We are reptilians of the kind called “saurian.” Our metabolic cooling system is all inside our body. It is where we continuously pump air, and -- yes -- we do sweat, in the sense that we evaporate water. But inside, not outside! It is much more efficient than the method that the naked apes use. But, on the whole, these creatures are resourceful and clever, and if we ever were to come to fight each other, well, it would be an interesting story.

-- Meuianga, you really think that Earth’s apes could defeat the mighty Reptilian Stellar Empire?

-- That could never be!

-- We can’t even imagine such a thing.

You never know, cadets, you never know…..

Lectures by Meuianga Mera

Why Naked Apes have Small Mouths. Explained by Meuianga Mera, Chief Scientist of the Reptilian Starfleet

The Red Mouthed Apes: A Lecture by Meuianga Mera, Chief Scientific Officer of the Reptilian Starfleet

The Naked Ape -- A Tale Told in Space

The Reptilian Mirage Suit: Learning the Purpose of Human Ears

The Evolutionary Game: How did Elephants survive the onslaught

Of Mammophants and Holobionts

A question for you, space cadets, why did Mammoths go extinct, while elephants didn't? You have to detect a subtle clue that has to do with how the naked apes hunted them. You should be able to see it in this image. (Meuianga Mera, Chief Scientific Officer of the Reptilian Starfleet)

From "The Embryo Project"

Revive & Restore’s Woolly Mammoth Revival Project

By: Risa Aria Schnebly
Published: 2021-01-19
Keywords: mammophant, de-extinction, gene modification

Gratefully reproduced on "The Proud Holobionts" under this text's Creative Commons License 

In 2015, Revive & Restore launched the Woolly Mammoth Revival Project with a goal of re-engineering a creature with genes from the woolly mammoth and introducing it back into the tundra to combat climate change. Revive & Restore is a nonprofit in California that uses genome editing technologies to enhance conservation efforts in sometimes controversial ways. In order to de-extinct the woolly mammoth, researchers theorize that they can manipulate the genome of the Asian elephant, which is the mammoth’s closest living evolutionary relative, to make it resemble the genome of the extinct woolly mammoth. While their goal is to create a new elephant-mammoth hybrid species, or a mammophant, that looks and functions like the extinct woolly mammoth, critics have suggested researchers involved in the project have misled and exaggerated the process. As of 2021, researchers have not yet succeeded in their efforts to de-extinct the woolly mammoth, but have expressed that it may become a reality within a decade.

Researchers broadly define de-extinction as a method for reintroducing extinct species. However, the methods of de-extinction that researchers participating in the Woolly Mammoth Revival Project pursue would not lead to a perfect biological replica of a mammoth. The only chance to precisely recreate an extinct animal would be through cloning, a process of creating a genetically identical organism using the DNA of a host. DNA is the genetic information found in every living organism that carries the instructions an organism needs to develop, live, and reproduce. However, researchers cannot clone mammoths because cloning requires living cells, whereas other genome editing methods do not. Since one of the last species of mammoths went extinct around 4000 years ago, scientists are unable to acquire any living cells needed to clone the animal itself.

Because cloning is not an option in the case of the woolly mammoth, Revive & Restore researchers are attempting to use genome editing and engineering to make mammoth-like species instead of perfect replications of mammoths. Genome engineering is a technique that enables researchers to make changes to an organism’s genome, which is its set of DNA. There are many technologies that equip scientists to edit an organism’s genome and change how it will develop and function. Researchers from the Woolly Mammoth Revival Project are experimenting with CRISPR-cas9, a genome editing tool derived from bacteria that involves cutting out specific sequences of DNA and replacing them with other sequences. In the case of the de-extinction of the woolly mammoth, scientists would edit the Asian elephant genome to make it more similar to the genome from the woolly mammoth.

As the woolly mammoth’s closest living relative, the Asian elephant is ninety-nine percent genetically identical to the mammoth without any genetic editing interventions. Genetic engineers can use CRISPR-cas9 to cut out and remove precise sequences of elephant DNA and replace them with the DNA sequences that make up specific genes in the woolly mammoth’s genome. The genes they add into the elephant genome code for features that can make an elephant more mammoth-like, such as promoting the development of thicker layers of fat and longer hair. Researchers will not have created a biological woolly mammoth once an organism with that genome develops. However, it would theoretically be a mammoth-like creature which some have researchers have called a mammophant. They speculate the organism will be able to survive in the Arctic, where woolly mammoths once lived to promote biodiversity in that area. Researchers at Revive & Restore expect the introduction of their hybrid species can help prevent the melting of permafrost, the thick layer of soil and bedrock that stays frozen year-round in the Arctic, thereby preventing the release of greenhouse gases.

Stewart Brand and Ryan Phelan founded Revive & Restore in 2012, launching its inception with a project designed to de-extinct the passenger pigeon, a species of bird that went extinct in the early twentieth century due to overhunting. The extinction of the passenger pigeon was one of the catalysts for the US conservation movement because it demonstrated how human action alone could entirely eradicate a species that was once extremely abundant. For Revive & Restore, the passenger pigeon was a model candidate for de-extinction not only because of its fame within the conservation movement, but also because the passenger pigeon was an important species in the forests of the eastern US. Its foraging and migration patterns helped to create areas within forests that allowed other species to populate.

Revive & Restore’s next species of focus was the woolly mammoth, which was an important species in the Arctic, where the mammoth would trample plants and trees which would enable the arctic permafrost to remain frozen by exposing it the cold air. In 2012, Brand and Phelan hosted a meeting of international scientists interested in the project to discuss the feasibility of reintroducing the woolly mammoth, or a species very similar. Two of the project’s key figures, scientists George Church and Sergey Zimov, met at that meeting and discussed its practicality. Church, a professor of genetics at Harvard Medical School in Boston, Massachusetts, had the scientific expertise needed to engineer a mammophant. Zimov, a researcher of ecology from Russia, could provide a place the mammophants could live, and suggested the potential role of the mammophant in combatting global warming.

In 1996, Zimov founded Pleistocene Park, a fifty square mile wide nature reserve in the remote Siberian Arctic where mammophants may eventually roam. Some of the goals of Pleistocene Park include restoring the area’s ecosystem, protect the permafrost, and prevent further global warming. Zimov had already reintroduced large grazing animals into the park to replace the wildlife that existed in that region in the late Pleistocene era, which was a span in Earth’s history that ended about 12,000 years ago. Zimov believes that reintroducing large species like mammophants could mitigate the effects of global warming in the Arctic by helping to prevent the thawing of arctic permafrost.

During the late Pleistocene era, mammoths and other large animals trampled and scraped snow away from the ground, exposing the permafrost to cold winter air that could penetrate the ground and keep the deep layers of the permafrost frozen. Without the activity from large animals, there is nothing to disturb the snow that covers the ground, which means the colder air cannot reach and freeze the permafrost during the winter. That means that the permafrost can melt more easily upon the arrival of seasonal warm weather, especially as global temperatures rise due to global warming. When arctic permafrost thaws, it can release greenhouse gases that have been trapped within it for centuries. Those greenhouse gases can trap heat inside the earth’s atmosphere and researchers predict its impact will be greater than any other factor contributing to global warming. However, according to Zimov, the reintroduction of large grazing animals into Pleistocene Park has already seemed to help keep deeper layers of the permafrost frozen. After Church visited Pleistocene Park himself in 2015, Church and Zimov launched the Woolly Mammoth Revival Project with Revive & Restore.

Before genetic engineers can begin to add mammoth genes into the elephant genome, they first have to identify which genes are the most critically involved in the features they hope to emulate. The mammoth genome was first sequenced in 2008 by a team of biologists at Penn State University in State College, Pennsylvania. The team used samples of mammoth hair found in two mammoth specimens buried in the Siberian permafrost, one that was 20,000 years old and another that was 60,000 years old. Though most DNA specimens that old would be too degraded for scientists to sequence, the mammoths had been frozen and preserved in the Siberian permafrost. However, the mammoth’s DNA sequence does not specifically communicate the associated genes. To determine those genes, researchers have tested and compared the sequences of the woolly mammoth to those of the Asian elephant.

Scientists can reprogram the cells they edit to become different kinds of cells in the body, such as red blood cells, hair cells, or tissue cells. By pushing the edited reprogrammed cells to develop, the team can then see what the outcome of the genome edits they make will be. For example, if the researchers splice in a gene meant to give the elephant longer, mammoth-like hair, they can then push the group of cells they edited to develop into actual hair cells through genetic engineering without ever having to create an actual organism. They can then see what the creature’s hair will actually look and feel like, how long it will grow, and how thick it will be, among many other things. Then researchers can see whether the edits they made will really make the elephant more cold-resistant or not. After testing to confirm that the gene edits have the outcome the researchers wanted, the researchers can then combine all their successful edits into one genome sequence that they will use to create an animal.

As of 2020, Church continued to lead one of the teams working to identify the important genes within the woolly mammoth genome with the use of CRISPR-cas9. One of the most recent updates from Church’s lab in 2017 announced that they had successfully located forty-five genes that code for traits to make the hybrid more resistant to cold weather. Though there are several thousand genetic differences between the genome of the mammoth and Asian elephant, Church has hypothesized in some interviews that his team may only need to splice in fifty of the mammoth genes to create a mammophant capable of surviving in the Arctic.

Out of concern for animal welfare, Church and his team have stated they plan to avoid forcing Asian elephants to act as a surrogate for the mammophant by growing the mammophant embryo in an artificial womb outside of the body instead. Additionally, the team can test the physical effects of changing and combining the genomes without having to produce an actual animal. Asian elephants are an endangered species as of 2020, so scientists have used genome editing technologies for early investigations into proving the feasibility of the concept. Additionally, critics such as Matthew Cobb, a professor of zoology at the University of Manchester in Manchester, England, doubt that scientists can achieve the capability to produce a functional artificial womb within the next decade. Cobb explained that an artificial womb would deprive a fetus from many important pre-birth interactions with its gestational carrier that help the fetus to properly develop. However, Church and his lab have conducted early experiments attempting to grow mouse embryos ex vivo, or out of a uterus, rather than in vivo, meaning in a uterus, and have suggested the technology will become possible within the next decade.

Even if the technology may soon be feasible, many critics question whether we should be trying to de-extinct the mammoth at all. For example, David Ehrenfeld, a professor of biology at Rutgers University in Camden, New Jersey, has raised concerns that the mammophants may not be able to survive in the Arctic because they are genetically different from the extinct mammoths and will not be able to learn survival skills without a herd. He suggests those factors could also lead the mammophants to behave unpredictably in their environment and possibly even cause more destruction than help. To avoid that problem, Revive & Restore has stated plans to raise eventual mammophants with captive Asian elephant families in zoos who may teach them survival and herding behaviors so the mammophants can one day form herds of their own.

Additionally, many ethicists have expressed concern over de-extinction being an immoral endeavor. De-extinction, if successful, may eventually undermine the conservation movement by making extinction seem like less of a problem. If extinction suddenly seems reversible, the public may feel less responsible for behaviors and actions that contribute global warming and biodiversity loss. For example, Ben Minteer, a professor of environmental ethics at Arizona State University in Tempe, Arizona, has noted that the premise of de-extinction may teach people that technology alone can reinforce the idea that human will remain unaccountable for changing their behaviors to prevent such damage from occurring in the first place. Other conservationists like Stuart Pimm, a professor of conservation ecology at Duke University in Durham, North Carolina, worry that the time, money, and effort dedicated to de-extinction efforts like the Woolly Mammoth Revival Project could divert important funds dedicated to protecting the many endangered species and ecosystems still around today. Additionally, journalists have suggested the notion of the topic entirely became manipulated with aggrandized and sensationalist headlines without regard to the restrictions and hindrances scientists will need to overcome before making it a reality.

As of 2021, the Woolly Mammoth Revival Project was still in the process of revising the elephant genome. Whether or not the project is ultimately successful, the scientific and public discussion on de-extinction has prompted questions that consider how far humans should be allowed to interfere with nature. Although humans may be responsible for behaviors that have led to global warming, the risks and uncertainty surrounding de-extinction may outweigh the benefits of correcting such mistakes.

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Campagna, Claudio, Daniel Guevara, and Bernard Le Boeuf. “De-Scenting Extinction: The Promise of De-Extinction May Hasten Continuing Extinctions.” Hastings Center Report 47 (2017): 48–53. https://onlinelibrary.wiley.com/doi/pdf/10.1002/hast.752 (Accessed July 26, 2020).
Clayton, Susan. “Preserving the Things We Value.” Center for Humans & Nature, 2015. https://www.humansandnature.org/conservation-extinction-susan-clayton (Accessed July 26, 2020).
Devlin, Hannah. “Woolly Mammoth on Verge of Resurrection, Scientists Reveal.” The Guardian, 2017. https://www.theguardian.com/science/2017/feb/16/woolly-mammoth-resurrection-scientists (Accessed July 26, 2020).
Ehrenfeld, David. “Resurrected Mammoths and Dodos? Don’t Count On It.” The Guardian, 2013. https://www.theguardian.com/commentisfree/2013/mar/23/de-extinction-efforts-are-waste-of-time-money (Accessed July 26, 2020).
Hawks, John. “How Mammoth Cloning Became Fake News: George Church, Artificial Wombs, Elephant Embryos, and a Gullible, Science Media.” Medium Science, 2017. https://medium.com/@johnhawks/how-mammoth-cloning-became-fake-news-1e3a80e54d42 (Accessed July 26, 2020).
Hysolli, Eriona. “An American-Russian Collaboration to Repopulate Siberia with Woolly Mammoths… Or Something Similar.” Medium, 2018. https://medium.com/@eriona.hysolli/an-american-russian-collaboration-to-repopulate-siberia-with-woolly-mammoths-or-something-similar-9cbac4e985cb (Accessed July 26, 2020).
Minteer, Ben, The Fall of the Wild: Extinction, De-Extinction, and the Ethics of Conservation. New York, New York: Columbia University Press, 2019.
Nijhuis, Michelle. “Don’t Think of a Mammophant.” Last Word on Nothing, 2017. https://www.lastwordonnothing.com/2017/03/07/dont-think-of-a-mammophant/ (Accessed July 26, 2020).
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Riederer, Rachel. “The Wooly Mammoth Lumbers Back Into View.” The New Yorker, 2018. https://www.newyorker.com/science/elements/the-wooly-mammoth-lumbers-back-into-view (Accessed July 26, 2020).
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“The Great Passenger Pigeon Project.” Revive & Restore. https://reviverestore.org/about-the-passenger-pigeon/ (Accessed July 26, 2020).
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Wood, Charlie. “We Can Clone a Mammoth: But Should We?” Christian Science Monitor, 2017. https://www.csmonitor.com/Science/2017/0216/We-can-clone-a-woolly-mammoth.-But-should-we (Accessed July 26, 2020).
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How to citeSchnebly, Risa Aria, "Revive & Restore’s Woolly Mammoth Revival Project". Embryo Project Encyclopedia (2021-01-19). ISSN: 1940-5030 http://embryo.asu.edu/handle/10776/13209.

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PublisherArizona State University. School of Life Sciences. Center for Biology and Society. Embryo Project Encyclopedia.
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Copyright Arizona Board of Regents Licensed as Creative Commons Attribution-NonCommercial-Share Alike 3.0 Unported (CC BY-NC-SA 3.0) http://creativecommons.org/licenses/by-nc-sa/3.0/
Last modified Monday, June 28, 2021 - 04:06
TopicTheories, Technologies, Organizations, Ethics
SubjectExtinction, Biological; Extinction, Species; Genetic Engineering; Genetically Engineered Organisms; Genetically Engineered Animals; Genetically Modified Animals; Cloning, Organism; Mammoths; Woolly Mammoth; Mammuthus primigenius; Mammuthus; Conservation; Animal diversity conservation; Animal conservation; Gene Editing; Bioethics; Life sciences--Moral and ethical aspects; Conceptniversity, 1711 South Rural Road, Tempe Arizona 85287, United States

When the Ice Will be Gone: The Greatest Change Seen on Earth in 30 Million Years.

 

 

An image from the 2006 movie "The Meltdown," the second of the "Ice Ages" series. These movies attempted to present a picture of Earth during the Pleistocene. Of course, they were not supposed to be paleontology classes, but they did show the megafauna of the time (mammoths, sabertooth tigers, and others) and the persistent ice, as you see in the figure. The plot of "The Meltdown" was based on a real event: the breakdown of the ice dam that kept the Lake Agassiz bonded inside the great glaciers of the Laurentide, in the North American continent. When the dam broke, some 15,000 years ago, the lake flowed into the sea in a giant flood that changed Earth's climate for more than a thousand years. So, the concept of ice ages as related to climate change is penetrating the human memesphere. It is strange that it is happening just when the human activity is pushing the ecosystem back to a pre-glacial period. If it happens, it will be the greatest change seen on Earth in 30 million years

 

We all know that there is permanent ice at Earth's poles: it forms glaciers and it covers huge areas of the sea. But is it there by chance, or is it functional in some way to Earth's ecosphere? 

Perhaps the first to ask this question was James Lovelock, the proposer (together with Lynn Margulis) of the concept of "Gaia" -- the name for the great holobiont that regulates the planetary ecosystem. Lovelock has always been a creative person and in his book "Gaia: A New Look at Life on Earth"  (1979) he reversed the conventional view of ice as a negative entity. Instead, he proposed that the permanent ice at the poles was part of the planetary homeostasis, actually optimizing the functioning of the ecosphere. 

Lovelock was perhaps influenced by the idea that the efficiency of a thermal engine is directly proportional to the temperature differences that a circulating fluid encounters. It may make sense: permanent ice creates large temperature difference between the poles and the equator and, as a consequence, winds and ocean currents are stronger, and the "pumps" that bring nutrients everywhere sustain more life. Unfortunately, this idea is probably wrong, but Lovelock has the merit to have opened the lid on a set of deep questions on the role of permanent ice in the ecosystem. What do we know about this matter?

It took some time for our ancestors to realize that permanent ice existed in large amounts in the high latitude regions. The first who saw the Northern ice sheet was probably Eric the Red, the Norwegian adventurer, when he traveled to Greenland around the year 1000. But he had no way to know the true extent of the inland ice, and he didn't report about them.

The first report I could find on Greenland's ice sheet is the 1820 "History Of Greenland", a translation of an earlier report (1757) in German by David Crantz, where you can find descriptions of the ice-covered inland mountains. By the early 20th century, the maps clearly showed Greenland as fully ice-covered. About Antarctica, by the end of the 19th century, it was known that it was also fully covered with a thick ice sheet. 

Earlier on, in the mid 19th century, Louis Agassiz had proposed a truly revolutionary idea: that of the ice age. According to Agassiz, in ancient times, much of Northern Europe and North America were covered with thick ice sheets. Gradually, it became clear that there had not been just one ice age, but several, coming and going in cycles. In 1930, Milutin Milankovich proposed that these cycles were linked to periodic variations in the insulation of the Northern Hemisphere, in turn caused by cycles in Earth's motion. For nearly a million years, Earth was a sort of giant pendulum in terms of the extent of the ice sheet. 

The 2006 movie "An inconvenient truth" was the first time when these discoveries were presented to the general public. Here we see Al Gore showing the temperature data of the past half million years.

An even more radical idea about ice ages appeared in 1992 when Joseph Kirkschvink proposed the concept of "Snowball Earth." The idea is that Earth was fully covered by ice at some moment around 700-600 million years ago, the period appropriately called "Cryogenian."

This super-ice age is still controversial: it will never be possible to prove that every square kilometer of the planet was under ice and there is some evidence that it was not the case. But, surely, we are dealing with a cooling phase much heavier than anything seen during relatively recent geological times.

While more ice ages were discovered, it was also clear that Earth was ice-free for most of its long existence. Our times, with permanent ice at the poles, are rather exceptional. Let's take a look at the temperatures of the past 65 million years (the "Cenozoic"). See this remarkable image (click to see it in high resolution)

At the beginning of the Cenozoic, Earth was still reeling after the great disaster of the end of the Mesozoic, the one that led to the disappearance of the dinosaurs (by the way, almost certainly not related to an asteroidal impact). But, from 50 million years ago onward, the trend has been constant: cooling. 

The Earth is now some 12 degrees centigrade colder than it was during the "warmhouse" of the Eocene. It was still ice-free up to about 35 million years ago but, gradually, permanent ice started accumulating, first in the Southern hemisphere, then in the Northern one. During the Cenozoic, Earth never was so cold as it is now.

The reasons for the gradual cooling are being debated, but the simplest explanation is that it is due to the gradual decline of CO2 concentrations in the atmosphere over the whole period. That, in turn, may be caused to a slowdown of the outgassing of carbon from Earth's interior. Maybe Earth is just becoming a little older and colder, and so less active in terms of volcanoes and similar phenomena. There are other explanations, including the collision of India with Central Asia and the rise of the Himalaya that caused a drawdown of CO2 generated by the erosion of silicates. But it is a hugely complicated story and let's not go into the details.

Let's go back to our times. Probably you heard how, just a few decades ago, those silly scientists were predicting that we would go back to an ice age. That's an exaggeration -- there never was such a claim in the scientific literature. But it is true that the idea of a new ice age was floating in the memesphere, and for good reasons: if the Earth had seen ice ages in the past, why not a new one? Look at these data:

These are temperatures and CO2 concentrations from the Vostok ice cores, in Antarctica (you may have seen these data in Al Gore's movie). They describe the glacial cycles of the past 400,000 years. Without going into the details of what causes the cycles (solar irradiation cycles trigger them, but do not cause them), you may note how low we went in both temperatures and CO2 concentrations at the coldest moments of the past ice ages. The latest ice age was especially cold and associated with very low CO2 concentrations. 

Was Earth poised to slide down to another "snowball" condition? It cannot be excluded. What we know for sure is that during the past million years or so, the Earth tethered close to the snowball catastrophe every 100,000 years or so. What saved it from sliding all the way into an icy death?

There are several factors that may have stopped the ice from expanding all the way to the equator. For one thing, the sun irradiation is today about 7% larger than it was at the time of the last snowball episode, during the Cryogenian. But that may not have been enough. Another factor was that the cold and the low CO2 concentrations may have led to a weakening -- or even to a stop -- of the biological pump in the oceans and of the biotic pump on land. Both these pumps cycle water and nutrients, keeping the biosphere alive and well. Their near disappearance may have caused a general loss of activity of the biosphere and, hence, the loss of one of the mechanisms that removes CO2 from the atmosphere. So, CO2 concentrations increased as a result of geological emissions. Note how, in the figure, the CO2 concentration and temperatures are perfectly superimposable: the reaction of the temperature to the CO2 increase was instantaneous on a geological time scale. Another factor may have been the desertification of the land that led to an increase in atmospheric dust that landed on the top of the glaciers. That lowered the albedo (the reflected fraction of light) of the system and led to a new warming phase. A very complicated story that is still being unraveled. But how close was the biosphere to total disaster? We will never know.

What we know is that, 20 thousand years ago, the atmosphere contained just 180 parts per million (ppm) of CO2 (today, we are at 410 ppm). That was close to the survival limit of green plants and there is evidence of extensive desertification during these periods. Life was hard for the biosphere during the recent ice ages, although not so bad as in the Cryogenian. Lovelock's idea that permanent ice at the poles is good for life just doesn't seem to be right.

Of course, the idea that we could go back to a new ice age was legitimate in the 1950s, not anymore as we understand the role of human activities on climate. Some people maintain that it was a good thing that humans started burning fossil hydrocarbons since that "saved us from a new ice age." Maybe, but this is a classic case of too much of a good thing. We are pumping so much CO2 into the atmosphere that our problem is now the opposite: we are not facing an "icehouse Earth" but a "warmhouse" or even a "hothouse" Earth. 

A "hothouse Earth" would be a true disaster since it was the main cause of the mass extinctions that took place in the remote past of our planet. Mainly, the hothouse episodes were the result of outbursts of CO2 generated by the enormous volcanic eruptions called "large igneous provinces." In principle, human emissions can't even remotely match these events. According to some calculations, we would need to keep burning fossil fuels for 500 years at the current rates to create a hothouse like the one that killed the dinosaurs (but, there is always that detail that non linear systems always surprise you . . .)

Still, considering feedback effects such as the release of methane buried in the permafrost, it is perfectly possible that human emissions could bring CO2 concentrations in the atmosphere at levels of the order of 600-800 ppm, or even more, comparable to those of the Eocene, when temperatures were 12 degrees higher than they are now. We may reach the condition called, sometimes, "warmhouse Earth."

From the human viewpoint, it would be a disaster. If the change were to occur in a relatively short time, say, of the order of a few centuries, the human civilization is probably toast. We are not equipped to cope with this kind of change. Just think of what happened some 14,500 years ago, when the great Laurentide ice sheet in North America fragmented and collapsed. (image source) (the 2006 movie "Meltdown" was inspired exactly by this event). Earth's climate went through a series of cold and warm spells that is hard to think we could survive. 

 

Human survival concerns are legitimate, but probably irrelevant in the greater scheme of things. If we go back to the Eocene, the ecosystem would take a big hit during the transition, but it would survive and then adapt to the new conditions. In terms of life, the Eocene has been described as "luxuriant." With plenty of CO2 in the atmosphere, forests were thriving and, probably, the biotic pump provided abundant water everywhere inland, even though the temperatures were relatively uniform at different latitudes. A possible mental model for that period is the modern tropical forests of Central Africa or Indonesia. We don't have data that would allow us to compare Earth's productivity today with that of the Eocene, but we can't exclude that the Eocene was more productive in terms of life. Humans might well adapt to this new world, although their survival during the transition is by no means guaranteed. 

Again, it seems that Lovelock was wrong when he said that ice ages optimize the functioning of the biosphere. But maybe there is more to this idea. At least for one thing, ice ages have a good effect on life. Take a look at this image that summarizes the main ice ages of Earth's long history

 (image source)

The interesting point is that ice ages seem to occur just before major transitions in the evolutionary history of Earth. We don't know much about the Huronian ice age, but it occurred just at the boundary of the Archean and the Proterozoic, at the time of the appearance of the Eucaryotes. Then, the Cryogenian preceded the Ediacaran period and the appearance of multicellular life that colonized the land. Finally, even the evolution of the Homo Sapiens species may be related to the most recent ice age cycle. With the cooling of the planet and the reduction of the extent of forested areas, our ancestors were forced to leave the comfortable forests where they had lived up to then and take up a more dangerous lifestyle in the savannas. And you know what it led to!

So, maybe there is something good in ice ages and, after all, James Lovelock's intuition may have hinted at an important insight in how evolution works. Then, there remains the question of how exactly ice ages drive evolution. Maybe they have an active role, or maybe they are simply a parallel effect of the real cause that drives evolution, quite possibly the increasing concentration of atmospheric oxygen that has accompanied the biosphere over the past 2.7 billion years. Oxygen is the magic pill that boosts the metabolism of aerobic creatures -- what makes possible creatures like us. 

In any case, it is likely that ice ages will soon be a thing of the past on planet Earth. The effect of the human perturbation may be moderate and, when humans will stop burning fossil hydrocarbons (they have to, one day or another) the system may reabsorb the excess CO2 and gradually return to the ice age cycles of the past. That may occur in times of the order of at least several thousand years, possibly several tens of thousands. But the climate is a non-linear system and it may react by reinforcing the perturbation -- the results are unknowable. 

What we know for sure is that the cycle of Earth's ecosystem (Gaia) is limited. We still have about 600 million years before the sun's increasing brightness takes Earth to a different condition: that of "wet greenhouse" that will bring the oceans to boil and extinguish all life on the planet. And so it will be what it will have to be. Gaia is long-lived, but not eternal.