The Earth’s 6th Great Mass Extinction is Occurring as You Read This

“In one sense we know much less about Earth than we do about Mars. The vast majority of life forms on our planet are still undiscovered, and their significance for our own species remains unknown. This gap in our knowledge is a serious matter: we will never completely understand and preserve the living world around us at our present level of ignorance.

“If all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago. If insects were to vanish, the environment would collapse into chaos.”

Edward O. Wilson, The world’s leading authority on Biodiversity, Emeritus Professor of Biology at Harvard and author of “The Creation: An Appeal to Save Life on Earth.”

There is little doubt left in the minds of professional biologists that Earth is currently faced with a mounting loss of species that threatens to rival the five great mass extinctions of the geological past, the most devasting being the Third major Extinction (c. 245 mya), the Permian, where 54% of the planet’s species families lost. As long ago as 1993, Harvard biologist E.O. Wilson estimated that Earth is currently losing something on the order of 30,000 species per year — which breaks down to the even more daunting statistic of some three species per hour. Some biologists have begun to feel that this biodiversity crisis — this “Sixth Extinction” — is even more severe, and more imminent, than Wilson had supposed.

With the human population expected to reach 9-10 billion by the end of the century and the planet in the middle of its sixth mass extinction — this time due to human activity — the next few years are critical in conserving Earth’s precious biodiversity. The cause of the Sixth Extinction, Homo sapiens, means we can continue on the path to our own extinction, or, preferably, we modify our behavior toward the global ecosystem of which we are still very much a part.

At a casual glance, the physically caused extinction events of the past might seem to have little or nothing to tell us about the current Sixth Extinction, which is a human-caused event. For there is little doubt that humans are the direct cause of ecosystem stress and species destruction in the modern world through transformation of the landscape, overexploitation of species, pollution, and the introduction of alien species

The Sixth Extinction can be characterized as  the first recorded global extinction event that has a biotic, rather than a physical, cause, due to massive asteroid impact, volcanic eruptions.  Yet, looking deeper, human impact on the planet is a similar to the Cretaceous cometary collision. Sixty-five million years ago that extraterrestrial impact — through its sheer explosive power, followed immediately by its injections of so much debris into the upper reaches of the atmosphere that global temperatures plummeted and, most critically, photosynthesis was severely inhibited — wreaked havoc on the living systems of Earth, which is precisely what we are doing to the planet right now.

Phase two of the Sixth Extinction began around 10,000 years ago with the invention of agriculture-perhaps first in the Natufian culture of the Middle East. Agriculture appears to have been invented several different times in various different places, and has, in the intervening years, spread around the entire globe.

Agriculture, which began around 10,000 years ago in the Natufian culture of the Middle East, is a major engine driving the Sixth Extinction, represents the single most profound ecological change in the entire 3.5 billion-year history of life. With its invention humans did not have to interact with other species for survival, and so could manipulate other species for their own use nor did humans have to adhere to the ecosystem’s carrying capacity, and so could overpopulate

Homo sapiens became the first species to stop living inside local ecosystems. All other species, including our ancestral hominid ancestors, all pre-agricultural humans, and remnant hunter-gatherer societies still extant exist as semi-isolated populations playing specific roles (i.e., have “niches”) in local ecosystems. This is not so with post-agricultural revolution humans, who in effect have stepped outside local ecosystems. Indeed, to develop agriculture is essentially to declare war on ecosystems - converting land to produce one or two food crops, with all other native plant species all now classified as unwanted “weeds” — and all but a few domesticated species of animals now considered as pests.

Yet, upon further reflection, human impact on the planet is a direct analogue of the Cretaceous cometary collision. Sixty-five million years ago that extraterrestrial impact — through its sheer explosive power, followed immediately by its injections of so much debris into the upper reaches of the atmosphere that global temperatures plummeted and, most critically, photosynthesis was severely inhibited — wreaked havoc on the living systems of Earth. That is precisely what human beings are doing to the planet right now: humans are causing vast physical changes on the planet.

“The comparison I make between these big extinction events, prehistoric meteorite-caused or natural event-caused extinctions and the present one,” says E.O. Wilson, “is parallel to the difference between a heart attack and cancer. We understand that what we are doing is a slow but insidious, and only can be seen when you lay it out over the whole world over a period of decades. The hopeful thing about it is that this cancer can be treated. A lot of damage has been done, and it can be dangerous to us if we really just go on until half the species of organisms are extinct forever. Or we can halt the hemorrhaging.

“In terms of scale, it’s hard to put a figure on it,” Wilson adds: “We’re in a pronounced early stage of an extinction event that would probably be, by the end of this century if human activities continue unabated, right up to the Cretaceous level. We’re part way there. Whether you can say its 10 percent there or 25 percent there, a lot of it depends on the organisms you’re talking about. One estimate has it that, particularly when you throw in the mass extinction of the Pacific Island birds, which are the most vulnerable on Earth, something like 20 percent of bird species has been extinguished by human activities.”

Biocide is occurring at an alarming rate. Experts say that at least half of the world’s current species will be completely gone by the end of the century. Wild plant-life is also disappearing. Most biologists say that we are in the midst of an anthropogenic mass extinction. Numerous scientific studies confirm that this phenomenon is real and happening right now. Should anyone really care? Will it impact individuals on a personal level? Scientists say, “Yes!”

Critics argue that species disappear and new ones emerge all the time. That’s true, if you’re speaking in terms of millennia. Scientists acknowledge that species disappear at an estimated rate of one species per million per year, with new species replacing the lost ones at around the same rate. Recently humans have accelerated the extinction rate to where several entire species are annihilated every single day. The death toll artificially caused by humans is mind-boggling. Nature will take millions of years to repair what we destroy in just a few decades.

A recent analysis, published in the journal Nature, shows that it takes 10 million years before biological diversity even begins to approach what existed before a die-off. Over 10,000 scientists in the World Conservation Union have compiled data showing that currently 51 per cent of known reptiles, 52 per cent of known insects, and 73 per cent of known flowering plants are in danger along with many mammals, birds and amphibians. It is likely that some species will become extinct before they are even discovered, before any medicinal use or other important features can be assessed. The cliché movie plot where the cure for cancer is about to be annihilated is more real than anyone would like to imagine.

Research done by the American Museum of Natural History found that the vast majority of biologists believe that mass extinction poses a colossal threat to human existence, and is even more serious of an environmental problem than one of its contributors- global warming. The research also found that the average person woefully underestimates the dangers of mass extinction. Powerful industrial lobbies would like people to believe that we can survive while other species are quickly and quietly dying off. Irresponsible governments and businesses would have people believe that we don’t need a healthy planet to survive- even while human cancer rates are tripling every decade.

A lot of us heard about the recent extinction of the Yangtze river dolphin. It was publicized because dolphins are cute and smart, and we like dolphins. We were sort of sad that we humans were single-handedly responsible for destroying the entire millions-of-years-old species in just a few years through rampant pollution. Unfortunately the real death toll is so much higher than we hear on the news. Only a few endangered “celebrity favorites” get any notice at all.

Since animals and plants exist in symbiotic relationships to one another, extinction of one species is likely to cause ”co-extinctions”. Some species directly affect the health of hundreds of other species. There is always some kind of domino effect. This compounding process occurs with frightening speed. That makes rampant extinction similar too disease in the way that it spreads. Sooner or later- if gone unchecked- humans may catch it too.

Amphibians are a prime example at how tinkering with the environment can cause rapid animal death. For over 300 million years frogs, salamanders, newts and toads were hardy enough to precede and outlive the dinosaurs up until the present time. Now, within just two decades many amphibians are disappearing. Scientists are alarmed at how one seemingly robust species of amphibians will suddenly disappear within a few months.

The causes of biocide are a hodge-podge of human environmental “poisons” which often work synergistically, including a vast array of pollutants, pesticides, a thinning ozone layer which increases ultra-violet radiation, human induced climate change, habitat loss from agriculture and urban sprawl, invasions of exotic species introduced by humans, illegal and legal wildlife trade, light pollution, and man-made borders among other many other causes.

Is there a way out? The answer is yes and no. We’ll never regain the lost biodiversity-at least not within a fathomable time period, but there are ways to prevent a worldwide bio collapse, but they all require immediate action. Wilson, and other scientists point out that the world needs international cooperation in order to sustain ecosystems, since nature is unaware of artificially drawn borders. Humans love to fence off space they’ve claimed as their own. Sadly, a border fence often has terrible ecological consequences. One fence between India and Pakistan cuts off bears and leopards from their feeding habitats, which is causing them to starve to death. Starvation leads to attacks on villagers, and more slaughtering of the animals.

Some of the most endangered wildlife species live right in between the borderland area of the US and Mexico. These indigenous animals don’t know that they now live between two countries. They were here long before the people came and nations divided, but they will not survive if we cut them off from their habitat. The Sky Islands is one of many areas smack in the middle of this boundary where some of North America’s most threatened wildlife is found. Jaguars, bison, and Wolves have to cross through international terrain in the course of their life’s travels in order to survive. Unfortunately, illegal Mexican workers cross here too. People who know nothing of the wildlife’s biological needs want to create a large fence to keep out Mexicans, regardless of the fact that a fence would devastate these already fragile animal populations.

Wilson says the time has come to start calling the “environmentalist view” the “real-world view”. We can’t ignore reality simply because it doesn’t conform nicely within convenient boundaries and moneymaking strategies. What good will all of our money and conveniences do for us, if we collectively destroy the necessities of life?

There is hope, but it requires radical changes. Many organizations are lobbying for that change. One group trying to salvage ecosystems is called The Wildlands Project, a conservation group spearheading the drive to reconnect the remaining wildernesses. The immediate goal is to reconnect wild North America in four broad “mega-linkages”. Within each mega-linkage, mosaics of public and private lands, which would provide safe migrations for wildlife, would connect core areas. Broad, vegetated overpasses would link wilderness areas normally split by roads. They will need cooperation from local landowners and government agencies.

It is a radical vision to many people, and the Wildlands Project expects that it will take at least 100 years to complete. Even so, projects like this, on a worldwide basis, may be humanity’s best chance of saving what’s left of the planets eco-system, and the human race along with it.

Supercomputer unleashes virtual 9.0 megaquake in Pacific Northwest

Simulation may help big cities develop early warning systems

On January 26, 1700, at about 9 p.m. local time, the Juan de Fuca plate beneath the ocean in the Pacific Northwest suddenly moved, slipping some 60 feet eastward beneath the North American plate in a monster quake of approximately magnitude 9, setting in motion large tsunamis that struck the coast of North America and traveled to the shores of Japan.

Since then, the earth beneath the region – which includes the cities of Vancouver, Seattle and Portland — has been relatively quiet. But scientists believe that earthquakes with magnitudes greater than 8, so-called “megathrust events,” occur along this fault on average every 400 to 500 years.

To help prepare for the next megathrust earthquake, a team of researchers led by seismologist Kim Olsen of San Diego State University (SDSU) used a supercomputer-powered “virtual earthquake” program to calculate for the first time realistic three-dimensional simulations that describe the possible impacts of megathrust quakes on the Pacific Northwest region. Also participating in the study were researchers from the San Diego Supercomputer Center at UC San Diego and the U.S. Geological Survey.

What the scientists learned from this simulation is not reassuring, as reported in the Journal of Seismology, particularly for residents of downtown Seattle.

With a rupture scenario beginning in the north and propagating toward the south along the 600-mile long Cascadia Subduction Zone, the ground moved about 1 ½ feet per second in Seattle; nearly 6 inches per second in Tacoma, Olympia and Vancouver; and 3 inches in Portland, Oregon. Additional simulations, especially of earthquakes that begin in the southern part of the rupture zone, suggest that the ground motion under some conditions can be up to twice as large.

“We also found that these high ground velocities were accompanied by significant low-frequency shaking, like what you feel in a roller coaster, that lasted as long as five minutes – and that’s a long time,” said Olsen.

The long-duration shaking, combined with high ground velocities, raises the possibility that such an earthquake could inflict major damage on metropolitan areas — especially on high-rise buildings in downtown Seattle. Compounding the risks, like Los Angeles to the south, Seattle, Tacoma, and Olympia sit on top of sediment-filled geological basins that are prone to greatly amplifying the waves generated by major earthquakes.

“One thing these studies will hopefully do is to raise awareness of the possibility of megathrust earthquakes happening at any given time in the Pacific Northwest,” said Olsen. “Because these events will tend to occur several hundred kilometers from major cities, the study also implies that the region could benefit from an early warning system that can allow time for protective actions before the brunt of the shaking starts.” Depending on how far the earthquake is from a city, early warning systems could give from a few seconds to a few tens of seconds to implement measures, such as automatically stopping trains and elevators.

Added Olsen, “The information from these simulations can also play a role in research into the hazards posed by large tsunamis, which can originate from such megathrust earthquakes like the ones generated in the 2004 Sumatra-Andeman earthquake in Indonesia.” One of the largest earthquakes ever recorded, the magnitude 9.2 Sumatra-Andeman event was felt as far away as Bangladesh, India, and Malaysia, and triggered devastating tsunamis that killed more than 200,000 people.

In addition to increasing scientific understanding of these massive earthquakes, the results of the simulations can also be used to guide emergency planners, to improve building codes, and help engineers design safer structures — potentially saving lives and property in this region of some 9 million people.

Even with the large supercomputing and data resources at SDSC, creating “virtual earthquakes” is a daunting task. The computations to prepare initial conditions were carried out on SDSC’s DataStar supercomputer, and then the resulting information was transferred for the main simulations to the center’s Blue Gene Data supercomputer via SDSC’s advanced virtual file system or GPFS-WAN, which makes data seamlessly available on different – sometimes distant – supercomputers.

Coordinating the simulations required a complex choreography of moving information into and out of the supercomputer as Olsen’s sophisticated “Anelastic Wave Model” simulation code was running. Completing just one of several simulations, running on 2,000 supercomputer processors, required some 80,000 processor hours – equal to running one program continuously on your PC for more than 9 years!

“To solve the new challenges that arise when researchers need to run their codes at the largest scales, and data sets grow to great size, we worked closely with the earthquake scientists through several years of code optimization and modifications,” said SDSC computational scientist Yifeng Cui, who contributed numerous refinements to allow the computer model to “scale up” to capture a magnitude 9 earthquake over such a vast area.

In order to run the simulations, the scientists must recreate in their model the components that encompass all the important aspects of the earthquake. One component is an accurate representation of the earth’s subsurface layering, and how its structure will bend, reflect, and change the size and direction of the traveling earthquake waves. Co-author William Stephenson of the USGS worked with Olsen and Andreas Geisselmeyer, from Ulm University in Germany, to create the first unified “velocity model” of the layering for this entire region, extending from British Columbia to Northern California.

Another component is a model of the earthquake source from the slipping of the Juan de Fuca plate underneath the North American plate. Making use of the extensive measurements of the massive 2004 Sumatra-Andeman earthquake in Indonesia, the scientists developed a model of the earthquake source for similar megathrust earthquakes in the Pacific Northwest.

The sheer physical size of the region in the study was also challenging. The scientists included in their virtual model an immense slab of the earth more than 650 miles long by 340 miles by 30 miles deep — more than 7 million cubic miles — and used a computer mesh spacing of 250 meters to divide the volume into some 2 billion cubes. This mesh size allows the simulations to model frequencies up to 0.5 Hertz, which especially affect tall buildings.

“One of the strengths of an earthquake simulation model is that it lets us run scenarios of different earthquakes to explore how they may affect ground motion,” said Olsen. Because the accumulated stresses or “slip deficit” can be released in either one large event or several smaller events, the scientists ran scenarios for earthquakes of different sizes.

“We found that the magnitude 9 scenarios generate peak ground velocities five to 10 times larger than those from the smaller magnitude 8.5 quakes.”

The researchers are planning to conduct additional simulations to explore the range of impacts that depend on where the earthquake starts, the direction of travel of the rupture along the fault, and other factors that can vary.

Fertile wives find single men sexy

For partnered women, a manly man with no attachments seems sexiest when she is fertile.

Matt Kaplan

Whom do you fancy? When in a relationship, women’s preferences change over the course of their menstrual cycle.GETTY IMAGES

Women beware: instinctive preferences might up the odds of getting pregnant when cheating on a partner.

In a study looking at the ever-interesting (and ever-mysterious) question of why women are attracted to certain men, researchers found that sexual interest shifts with a partnered woman’s menstrual cycle. When fertile, women in relationships are most attracted to single men; when infertile their attraction shifts to coupled men¹.

The reason, the researchers suggest, is that coupled women who are thinking of having an affair (even when asked to think about it by researchers) subconsciously select a man who is more likely to be a willing partner when they are fertile. Courting a coupled man may be both a waste of time — as he is less likely to participate in an affair — and hazardous, as there is a greater chance of getting caught. “Ancestral women who felt more attracted to a single man than to an already coupled one would have been more likely than others to succeed and transmit this preference to their daughters,” says Paola Bressan of the University of Padua in Italy. “These subconscious preferences are apparently still with us.”

As for why women in relationships prefer coupled men during their non-fertile stage, Bressan thinks that the women are instinctively assessing these men as potential replacement partners. “A coupled man obviously has the skills to maintain a long-term relationship, whereas a single man is an unknown. Indeed, women tend to be suspicious of men who are still on the mating market,” Bressan says.

Single women showed no such variation in their preferences; they habitually showed no regard for whether a man was single or taken when expressing sexual preference, at any point in their cycle.

A man for all seasons

In many monogamous animals, including marmosets and humans, males of high genetic quality are less likely to invest time in paternal care than are those of lower genetic quality. The theory behind this is that females view males with good genes as so desirable to the quality of their offspring that they are willing to sacrifice help with the rearing, letting the men get away with not being around. Lower-quality males make up for their poorer genes by being supportive and aiding in child rearing.

Given these realities, one strategy for a female is to develop a long-term relationship with a lower-quality male while secretly breeding with single high-quality males. The only problem then is getting caught. Long-term partners will often attack an adulterous female in the animal world. In humans, the penalties can be equally stiff.

Bressan and colleague Debora Stranieri wondered whether these factors would drive women to be most interested in single men during their window of highest fertility.

Manly men

The team asked more than 200 women, half of whom were single, the other half in relationships, to rate the attractiveness of men in photographs described as single, married, in love, or with a girlfriend. When the same man was labelled as single rather than being in any kind of attachment, fertile women in relationships scored single men 13% higher than attached men; infertile women scored them 8% lower. The effect of fertile women’s preference for single men was most noticeable when those men had particularly ‘manly’ features, such as strong jaws, says Bressan.

<!– document.write(”); if ((!document.images && navigator.userAgent.indexOf(’Mozilla/2.’) >= 0) || (navigator.userAgent.indexOf(”WebTV”) >= 0)) { document.write(’‘); document.write(’‘); } //–>

The findings add to other studies looking at physiological changes and sexual behaviour associated with reproductive hormone cycles in women. Some work has shown that women are more amorous, for example, when at the fertile stage of their menstrual cycle — similar to the way that animals are ‘in heat’ near the fertile stage of their oestrus cycle.

“These findings provide additional evidence that oestrus in women, long believed to have been lost in human evolution, is alive and well,” says Eli Finkel, a psychologist at Northwestern University in Evanston, Illinois. They also have the alarming implication that adulterous women, instead of trying to avoid getting pregnant, will subconsciously tend to do the opposite. However, actual romantic behaviour is not the same as instinctive sexual preferences, says Finkel: both need to be intensively studied to better understand all of this.

Motvators

Top 5 Botched Marriage Proposals

Here’s the link:

http://www.letsgettight.com//blog/2008/2/25/top-5-botched-marriage-proposals.html

Venus Revealed: Probe Discovers Extraordinary Weather System of the Morning Star

Slowly but surely scientists are unraveling an incredible picture of our Solar System with each planet vastly differing from the next, but all featuring it’s own unique and mysterious beauty. The tan highland area in the center of the image left is called Aphrodite Terra, while the faint green circle to the lower right is a deep canyon named Artemis Chasma.

Named after the Roman goddess of love and beauty, Venus is also known as the “morning star” and “evening star” since it is visible at dawn and dusk to the naked eye, appearing as a bright, white disk from Earth. However, closer up, the planet’s cloudy atmosphere creates a process similar to “urban smog over cities.”

Venus is often called Earth’s twin as the two planets are close in size, but that’s where the similarity ends. The massive clouds that cover Venus create a greenhouse effect that keeps the planet at a sizzling 864°F. Now Venus Express has revealed our “twin” planet to be extraordinarily fast changing ‘global weather’ on an extremely large scale. Bright hazes can appear in a matter of days that reach from the south pole to the low southern latitudes and then quickly disappear. Venus’ bizarre weather patterns—unlike anything on Earth—has given scientists new mysteries to solve.

At visable wavelengths of light, the cloudy planet appears serene. All of that changes, however, when scientists switch to the ultraviolet, which reveals an exciting, and mysterious dynamic nature. Ever-changing stripes mark the planet, indicating regions where solar ultraviolet radiation is either absorbed or reflected, respectively.

Venus Express has seen some amazing things while monitoring the behavior of the planet’s atmosphere with its Venus Monitoring Camera (VMC). VMC has captured a series of images showing the development of the bright southern haze. Within days, the high-altitude veil continually brightened and dimmed, moving towards equatorial latitudes and back towards the pole again.

Such global weather suggests that unknown dynamical, chemical and microphysical processes are fast at work on the planet. During these episodes, the brightness of the southern polar latitudes increased by about a third and faded just as quickly. 

“This bright haze layer is made of sulphuric acid,” says Dmitri Titov, at the Max Planck Institute for Solar System Research in Germany. That composition suggests the existence of a formation process.

At 70 km and below, Venus’s carbon dioxide-rich atmosphere contains small amounts of water vapor and gaseous sulphur dioxide. normally buried in the cloud layer that blocks our view of the surface.

However, as atmospheric process lifts these molecules high up above the cloud tops, they are exposed to solar ultraviolet radiation. This breaks the molecules, making them highly reactive. The fragments find each other and combine quickly to form sulphuric acid particles, creating the think haze.

“The process is a bit similar to what happens with urban smog over cities,” says Titov.

What causes the water vapour and sulphur dioxide to well up in the first place? The team does not know yet. Titov says that it is likely some kind of internal dynamical process in the planet’s atmosphere, but the influence of solar activity has not been ruled out.

The dark markings, especially, remain one of the biggest mysteries of Venus’s atmosphere. They are caused by some kind of chemical species, absorbing solar ultraviolet radiation. However, planetary scientists do not yet know the identity of the chemical involved, but are eager to unlock the mystery as they continue to probe the mysteries of the “morning star”.

Posted by Rebecca Sato

* Adapted from an ESA release.

How it happened: The catastrophic flood that cooled the Earth

PARIS (AFP) - Canadian geologists say they can shed light on how a vast lake, trapped under the ice sheet that once smothered much of North America, drained into the sea, an event that cooled Earth’s climate for hundreds of years.

During the last ice age, the Laurentide Ice Sheet once covered most of Canada and parts of the northern United States with a frozen crust that in some places was three kilometres (two miles) thick.

As the temperature gradually rose some 10,000 years ago, the ice receded, gouging out the hollows that would be called the Great Lakes.

Beneath the ice’s thinning surface, an extraordinary mass of water built up — the glacial lake Agassiz-Ojibway, a body so vast that it covered parts of Manitoba, Saskatchewan, North Dakota, Ontario and Minnesota.

And then, around 8,200 years ago, Agassiz-Ojibway massively drained, sending a flow of water into the Hudson Strait and into the Labrador Sea that was 15 times greater than the present discharge of the Amazon River.

By some estimates, sea levels rose 14 metres (45 feet) as a result.

How the great flood was unleashed has been a matter of debate.

Some experts suggest an ice dam was smashed down, or the gushing water spewed out over the top of the icy lid.

Quebec researchers Patrick Lajeunesse and Guillaume Saint-Onge believe, though, that the outburst happened under the ice sheet, rather than above it or through it.

In a study appearing on Sunday in the journal Nature Geoscience, the pair describe how they criss-crossed Hudson Bay on a research vessel, using sonar to scan more than 10,500 kilometres (6,000 miles) to get a picture of the bay floor.

In the south of the bay, they found lines of deep waves in the sandy bed, stretching more than 900 kilometres (562 miles) in length and some 1.7 metres (5.5 feet) deep.

These are signs that the bay’s floor, protected by the mighty lid of ice, was swept by a mighty current many years ago but has been still ever since, they say.

In the west of the bay, they found curious marks in the shape of parabolas twisting around to the northeast.

The arcs were chiselled as much as three metres (10 feet) into the sea bed and found at depths of between 80 and 205 metres (260 and 666 feet).

The duo believe that this part of the bay had icebergs that were swept by the massive current.

The bergs’ jagged tips were trapped in the sea bed and acted like a pivot. As the icebergs swung around, other protruding tips ripped arc-like tracks on the bay floor.

Also presented as evidence are deep submarine channels and deposits of red sediment that stretch from land west of Hudson Bay right across the northwestern floor of the bay itself — both point to a current that swept all before it.

“Laurentide ice was lifted buoyantly, enabling the flood to traverse southern Hudson Bay under the ice sheet,” the study suggests.

Previous work suggests the flood was so huge that it affected climate around the world.

The influx of freshwater into the North Atlantic reduced ocean salinity so much that this braked the transport of heat flowing from the tropics to temperate regions.

Temperatures dropped by more than three degrees Celsius (5.4 degrees Fahrenheit) in Western Europe for 200-400 years — a mini-Ice Age in itself.