Apart from the global catastrophe that killed off most of the dinosaurs, some experts think almost all the mass extinctions in Earth’s history were followed by a proliferation of microbes in rivers and lakes.
After the Permian extinction event 252 million years ago – the largest mass extinction event in Earth’s history – there appears to have been a burst in bacterial and algal blooms, lasting for hundreds of thousands of years.
According to the geologic record in Australia, the damaging impacts of climate change and climate-driven deforestation during the Permian extinction event most likely caused a toxic soup to sprout in the Sydney Basin, one of the oldest known freshwater ecosystems in the world.
That’s disconcerting, the authors say, as human activity is leading to a similar mass extinction event today.
“We’re seeing more and more toxic algae blooms in lakes and in shallow marine environments that’s related to increases in temperature and changes in plant communities which are leading to increases in nutrient contributions to freshwater environments,” says geologist Tracy Frank from the University of Connecticut
“So, a lot of parallels to today. The volcanism was a source of CO2 in the past, but we know that the rate of CO2 input that was seen back then was similar to the rate of CO2 increases we’re seeing today because of anthropogenic effects.”
Algae and bacteria are normal parts of a healthy freshwater environment, but sometimes they can grow out of control and deplete the water of oxygen, creating ‘dead zones’.
This tends to happen with global warming, deforestation, and the rush of soil nutrients into waterways, which can feed microbes. All three of these factors are in play today, which is why we are probably seeing increases in toxic blooms already.
Considering what’s happened in the past, that’s a disturbing sign.
According to soil, fossil, and geochemical data from the Sydney Basin, researchers think the spread of microbes in the wake of the Permian extinction “was both a symptom of continental ecosystem collapse, and a cause of its delayed recovery.”
Volcanic eruptions in the Permian first triggered an accelerated and sustained rise in greenhouse gas emissions. This caused higher global temperatures and sudden deforestation due to wildfires or drought.
Once the trees were gone, it wasn’t long before the structure of the soil began to erode, and its nutrients slipped into freshwater ecosystems.
In turn, these persistent dead zones prevented the reestablishment of important carbon sinks, like peatlands, and slowed down climate and ecosystem recovery.
Other deep-time records around the world have also found microbial blooms are common after warming-driven extinction events. The exception seems to be the very large asteroid event that caused the mass extinction of dinosaurs 66 million years ago.
This major episode caused vast amounts of dust and sulfate aerosols to rise into the atmosphere, but compared to volcanic activity, the meteorite only caused a modest increase in atmospheric carbon dioxide and temperature, not a sustained one. As such, freshwater microbes only seemed to undergo a short-lived burst after the extinction event.
Unfortunately, that’s very different from what occurred during the Permian extinction and what is happening today.
For instance, the researchers note that the “optimal temperature growth range” of these harmful algae in freshwater environments is 20-32 °C (68-89.6 °F). That range matches the estimated continental summer surface air temperatures for the region during the early Triassic. That range is what’s projected for mid-latitude continental summer surface air temperatures in 2100.
Scientists are noticing other similarities, including an increase in forest fires and the subsequent destabilization of soils.
“The other big parallel is that the increase in temperature at the end of the Permian coincided with massive increases in forest fires,” says geologist Chris Fielding, also from the University of Connecticut.
“One of the things that destroyed whole ecosystems was fire, and we’re seeing that right now in places like California. One wonders what the longer-term consequences of events like that as they are becoming more and more widespread.”
The good news is that this time many of the changes are in our control. The bad news is that whatever happens next is our own fault.
“The end-Permian mass extinction event took four million years to recover from,” Fielding says. “That’s sobering.”
“The birds are emaciated – they are little more than skin and bone with many half their usual weight which is catastrophically low,” he added.
“They have been seen feeding very close to beaches in amongst swimmers, when normally they steer clear of people, and have been observed up to 20 miles up rivers, which is unheard of for this marine bird.
“These are signs that the birds are getting desperate in their search for food.”
Dr Daunt said the fact that the birds appeared to be starving “might suggest a lack of good quality fish in the sea” but the presence of many feeding flocks along the coasts suggested it was “caused by something else”.
Other birdwatchers have seen birds washed up in clusters with live birds “just bobbing about beyond the surf”, apparently not feeding.
Large colonies of guillemots nest annually on islands off the coasts of Scotland and Northumberland.
They spend most of their time at sea and come back to land to breed.
Senior curator in charge of birds at the Natural History Museum, Dr Alex Bond, said mass deaths, known as wrecks, were not unusual but usually occurred in winter and during bad weather.
“Guillemots spend most of their time on water, not on land, so a big storm can beat them up a bit,” he said.
“The fact we’re seeing lots of them in unusual places suggests this wreck is something quite different.”
The CEH is recording the number and location of dead birds and will carry out post-mortem examinations on their bodies.
It will then monitor breeding colonies next spring to see if numbers are reduced.
It’s not just animals that are at risk of dying out, the world’s crops are in rapid decline. Here’s why it matters what is on your plateDan SaladinoFri 17 Sep 2021 07.00 EDT
In eastern Turkey, in a golden field overshadowed by grey mountains, I reached out and touched an endangered species. Its ancestors had evolved over millions of years and migrated here long ago. It had been indispensable to life in the villages across this plateau, but its time was running out. “Just a few fields left,” the farmer said. “Extinction will come easily.” This endangered species wasn’t a rare bird or an elusive wild animal, it was food, a type of wheat: a less familiar character in the extinction story now playing out around the world, but one we all need to know.
To most of us, one field of wheat might look much like any other, but this crop was extraordinary. Kavilca (pronounced Kav-all-jah) had turned eastern Anatolian landscapes the colour of honey for 400 generations (about 10,000 years). It was one of the world’s earliest cultivated foods, and is now one of the rarest.
How can a food be close to extinction and yet at the same time appear to be everywhere? The answer is that one type of wheat is different from another, and many varieties are at risk, including ones with important characteristics we need to combat crop diseases or climate change. Kavilca’s rarity is emblematic of the mass extinction taking place in our food.Advertisement
Many aspects of our lives are becoming more homogeneous. We can shop from identical outlets, see the same brands and buy into the same fashions around the world. The same is true of our diet. In a short space of time it has become possible for us to eat the same food wherever we are, creating an edible form of uniformity. “But hang on,” you might say, “I eat a greater variety of foods than my parents or grandparents ever did.” And on one level, that is true. Whether you’re in London, Los Angeles or Lima, you can eat sushi, curry, or McDonald’s; bite into an avocado, banana or mango; sip a Coca-Cola, a Budweiser or a branded bottle of water. What we’re being offered appears at first to be diverse, until you realise it is the same kind of “diversity” that is spreading around the globe in identical fashion.
Consider these facts: the source of much of the world’s food – seeds – is mostly in the control of just four corporations; half of all the world’s cheeses are produced with bacteria or enzymes manufactured by a single company; one in four beers drunk around the world is the product of one brewer; from the US to China, most global pork production is based around the genetics of a single breed of pig; and, perhaps most famously, although there are more than 1,500 different varieties of banana, global trade is dominated by just one, the Cavendish.
The source of much of the world’s food – seeds – is mostly in the control of just four corporations
This level of uniformity has never been experienced before. The human diet has undergone more change in the last 150 years (roughly six generations) than in the entire previous one million years (around 40,000 generations). We are living and eating our way through one big unparalleled experiment.
For most of our evolution as a species, as hunter-gatherers and then as farmers, human diets were enormously varied. Our food was the product of a place and crops were adapted to a particular environment, shaped by the knowledge and the preferences of the people who lived there as well as the climate, soil, water and even altitude. This diversity was stored and passed on in the seeds farmers saved, in the flavours of the fruits and vegetables people grew, the breeds of animals they reared, the bread they baked, the cheeses they produced and the drinks they made.
Kavilca wheat is one of the survivors of disappearing diversity, but only just. It has a distinctive history and a connection to a specific part of the world and its people. It is only during our lifetimes that this singular grain, perfectly adapted to its environment and with a taste like no other, has become endangered and pushed to the brink of extinction. The same is true of many thousands of other crops and foods. We should all know their stories and the reasons for their decline, because our survival depends on it.
My entry into food journalism took place during a crisis. It was 2008, and while the world was mostly focusing on the financial turmoil ripping through the banking system, a momentous food story was also unfolding. Wheat, rice and maize prices were spiralling to record highs, tripling on global markets at their peak. This pushed tens of millions of the poorest people on Earth towards hunger and also fuelled the tensions that later exploded into the Arab spring. Riots and protests toppled governments in Tunisia and Egypt and helped trigger the conflict in Syria. For the first time in decades, people were asking serious questions about the future of our food. With 7.5 billion people on Earth and a projected 10 billion by 2050, crop scientists began telling the world that global harvests needed to increase by 70%. Calling for greater diversity seemed liked an indulgence. But now we’re starting to realise that diversity is essential for our future.
Evidence of this shift in thinking came in September 2019 at the climate action summit held at the United Nations headquarters in New York. Emmanuel Faber, then CEO of the dairy giant Danone, told the business leaders and politicians present that the food system the world had created over the last century was at a dead end. “We thought with science we could change the cycle of life and its rules,” he said, that we could feed ourselves with monocultures and base most of the world’s food supply on a handful of plants. This approach was now bankrupt, Faber explained. “We’ve been killing life and now we need to restore it.”
Faber was making a pledge to save diversity backed by 20 global food businesses, including Unilever, Nestlé, Mars and Kellogg’s – companies with combined annual food sales in 100 countries of about $500bn. At the event, Faber expressed concern that in parts of the dairy industry 99% of the cows are a single breed, the Holstein. “It’s oversimplistic now,” he said of the global food system. “We have a complete loss of diversity.”
If the businesses that helped create and spread homogeneity in our food are now voicing concerns over lost diversity, then we should all take notice. The enormity of what we’re losing is only now dawning on us, but if we act now, we can save it.Advertisementhttps://0a90b976fd064af9248bf032dfb3f569.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html
The decline in the diversity of our food, and the fact that so many foods have become endangered, didn’t happen by accident: it is an entirely human-made problem. The biggest loss of crop diversity came in the decades that followed the second world war when, in an attempt to save millions from starvation, crop scientists found ways to produce grains such as rice and wheat on a phenomenal scale. To grow the extra food the world desperately needed, thousands of traditional varieties were replaced by a small number of new super-productive ones. The strategy that ensured this – more agrochemicals, more irrigation, plus new genetics – came to be known as the “green revolution”.
Because of it, grain production tripled, and between 1970 and 2020 the human population more than doubled. But the danger of creating more uniform crops is that they become vulnerable to catastrophes. A global food system that depends on just a narrow selection of plants is at greater risk of succumbing to diseases, pests and climate extremes.
Although the green revolution was based on ingenious science, it attempted to oversimplify nature, and this is starting to backfire on us. In creating fields of identical wheat, we abandoned thousands of highly adapted and resilient varieties. Far too often their valuable traits were lost. We’re starting to see our mistake – there was wisdom in what went before.
Of the 6,000 plant species humans have eaten over time, the world now mostly eats just nine, of which just three – rice, wheat and maize – provide 50% of all calories. Add potato, barley, palm oil, soy and sugar (beet and cane) and you have 75% of all the calories that fuel our species. As thousands of foods have become endangered and extinct, a small number have risen to dominance. Take soy, domesticated in China thousands of years ago, a bean relatively obscure outside Asia until the 1970s and now one of the world’s most traded agricultural commodities. Used in feed for pigs, chickens, cattle and farmed fish, which in turn feed us, soy plays a starring role in an increasingly homogeneous diet eaten by billions of people. These dietary shifts taking place at a global level, all pointing towards uniformity, are unprecedented.Advertisement
An individual human diet even a few thousand years ago was far richer in diversity than the one most of us eat today. In the Jutland peninsula of western Denmark in 1950, peat diggers discovered the intact body of a man who had been executed (or possibly sacrificed) 2,500 years ago. Inside the man’s stomach was a porridge made with barley, flax and the seeds of 40 different plants. In present-day east Africa, the Hadza, who are among the last of the world’s hunter-gatherers, eat from a potential wild menu that consists of more than 800 plant and animal species, including numerous types of tubers, berries, leaves, small mammals, large game, birds and types of honey. We can’t replicate their diets in the industrialised world but we can learn from them.
I am not calling for a return to some kind of halcyon past. But I do think we should consider what the past can teach us about how to inhabit the world now and in the future. Our current food system is contributing to the destruction of the planet: one million plant and animal species are now threatened with extinction; we clear swathes of forests to plant immense monocultures and then burn through millions of barrels of oil a day to make fertilisers to feed them. We are farming on borrowed time.
I can’t claim saving endangered foods will provide answers to all of these problems, but I believe it should be part of the solution. Kavilca wheat, for example, can thrive in conditions so cold and damp that modern crops are guaranteed to fail. Bere barley is a food so perfectly adapted to the harsh environment of Orkney that no fertilisers or other chemicals are needed for it to grow. And murnong, a juicy, nutritious and once abundant root from southern Australia, is proof that the world has much to learn from indigenous peoples about eating more in harmony with nature.Advertisementhttps://0a90b976fd064af9248bf032dfb3f569.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html
The concept of being endangered and at risk of extinction is usually reserved for wildlife. Since the 1960s, the red list, compiled by the International Union for Conservation of Nature, has catalogued vulnerable plant and animal species (about 105,000 at the time of writing), highlighting those at risk of extinction (nearly 30,000).The way we eat is killing us – and the planetFelicity LawrenceRead more
A version of the red list dedicated solely to food was created in the mid-1990s by Italy’s Slow Food movement and named the Ark of Taste. The group that created it saw that when a food, a local product or crop became endangered, so too did a way of life, knowledge and skill, a local economy and an ecosystem. Their call to respect diversity captured the imaginations of farmers, cooks and campaigners from around the world, who started to add their own endangered foods to the Ark.
As I write, the Ark of Taste contains 5,312 foods from 130 countries, with 762 products on a waiting list ready to be assessed. I have met many people saving endangered foods, including the farmer who showed me the rare field of Kavilca wheat. There are likely to be other champions in your own part of the world. You can help, too, by finding the foods that are endangered in your area, whether an apple variety or a local cheese. By eating these, you can help to save them. Such foods represent much more than sustenance. They are history, identity, pleasure, culture, geography, genetics, science, creativity and craft. And our future.
This is an edited extract from Eating to Extinction by Dan Saladino, to be published by Jonathan Cape on 23
Using NASA’s Deep Space Network and state-of-the-art computer models, scientists were able to significantly shrink uncertainties in Bennu’s orbit, determining its total impact probability through the year 2300 is about 1 in 1,750 (or 0.057%). The researchers were also able to identify September 24, 2182, as the most significant single date in terms of a potential impact, with an impact probability of 1 in 2,700 (or about 0.037%). Credit: NASA’s Goddard Space Flight Center
Like Hitting a Bullseye With Your Eyes Closed
Two statisticians put into perspective the chances of asteroid Bennu striking Earth in the next 300 years.
Recently NASA updated its forecast of the chances that the asteroid Bennu, one of the two most hazardous known objects in our solar system, will hit Earth in the next 300 years. New calculations put the odds at 1 in 1,750, a figure slightly higher than previously thought.
The space agency, which has been tracking the building-sized rock since it was discovered in 1999, revised its prediction based on new tracking data.
Even with the small shift in odds, it seems likely we won’t face the kind of scenario featured that in the 1998 science-fiction disaster film “Armageddon” when Stamper, played by Bruce Willis, and his team had to try to blow up a huge asteroid that was on an extinction-making collision course with the Earth.
This mosaic of Bennu was created using observations made by NASA’s OSIRIS-REx spacecraft, which was in close proximity to the asteroid for over two years. Credit: NASA/Goddard/University of Arizona
(In an unrelated development, NASA plans to launch a mission in November to see whether a spacecraft could hit a sizeable space rock and change its trajectory just in case it ever needs to.)
This begs the question of just how good should we feel about our odds? We put that question to Lucas B. Janson and Morgane Austern, both assistant professors of statistics.
They compared Bennu’s chances of hitting Earth to the approximate likelihood of:
Flipping a coin and having the first 11 attempts all land heads.
Any four random people sharing a birthday in the same month (the odds of this are 1 in 1,750 exactly).
Throwing a dart at a dartboard with your eyes closed and hitting a bullseye.
Winning the state’s VaxMillions lottery on two separate days if every eligible adult resident is entered and a new drawing is held every second.
Bottom line? Janson, an affiliate in computer science, says that if he were a betting man, he would put his money on our being just fine. Then again, he points out, if he is wrong, “Paying up would be the least of my worries.”
Scientists have uncovered a fascinating new insight into what caused one of the most rapid and dramatic instances of climate change in the history of the Earth.
A team of researchers, led by Dr. Sev Kender from the University of Exeter, have made a pivotal breakthrough in the cause behind the Paleocene-Eocene Thermal Maximum (PETM) – an extreme global warming event that lasted for around 150 thousand years which saw significant temperature rises.
Although previous studies have suggested volcanic activity contributed to the vast CO2 emissions that drove the rapid climate change, the trigger for the event is less clear.
In the new study, the researchers have identified elevated levels of mercury just before and at the outset of the PETM – which could be caused by expansive volcanic activity – in samples taken from sedimentary cores in the North Sea.
Crucially, the research of the rock samples also showed that in the early stages of the PETM, there was a significant drop in mercury levels – suggested at least one other carbon reservoir released significant greenhouse gases as the phenomenon took hold.
The research indicates the existence of tipping points in the Earth’s System – which could trigger the release of additional carbon reservoirs that drove the Earth’s climate to unprecedented high temperatures.
The pioneering research, which also includes experts from the British Geological Survey, the University of Oxford, Herriot-Watt University and the University of California at Riverside, could give a fresh understanding of how modern-day climate change will affect the Earth in the centuries to come.
The research is published in Nature Communications on August 31th 2021.
Dr. Kender, a co-author on the study from the Camborne School of Mines, based at the University of Exeter’s Penryn Campus in Cornwall said: ”Greenhouse gasses such a CO2 methane were released to the atmosphere at the start of the PETM in just a few thousand years.
“We wanted to test the hypothesis that this unprecedented greenhouse gas release was triggered by large volcanic eruptions. As volcanoes also release large quantities of mercury, we measured the mercury and carbon in the sediment cores to detect any ancient volcanism.
“The surprise was that we didn’t find a simple relationship of increased volcanism during the greenhouse gas release. We found volcanism occurred only at the beginning phase, and so another source of greenhouse gasses must have been released after the volcanism.”
The PETM phenomenon, which is one of the most rapid periods of warming in the Earth’s history, occurred as Greenland pulled away from Europe.
While the reasons behind how such vast quantities of CO2 were released to trigger this extensive period of warming lay hidden for many years, scientists have recently suggested that volcanic eruptions were the main driver.
However, while carbon records and modeling have suggested vast amounts of volcanic carbon was released, it has not been possible to identify the trigger point for PETM – until now.
In the new study, the researchers studied two new sedimentary cores from the North Sea which showed high levels of mercury present, relative to organic carbon levels.
These samples showed numerous peaks in mercury levels both before, and at the outset of the PETM period – suggesting it was triggered by volcanic activity.
However, the study also showed that there was at least one other carbon reservoir that was subsequently released as the PETM took hold, as mercury levels appear to decline in the second part of its onset.
Dr. Kender added: “We were able to carry out this research as we have been working on exceptionally well preserved new core material with collaborators from the Geological Survey of Denmark and Greenland. The excellent preservation allowed detailed detection of both the carbon released to the atmosphere and the mercury. As the North Sea is close to the region of volcanism thought to have triggered the PETM, these cores were in an ideal position to detect the signals.
“The volcanism that caused the warming was probably vast deep intruded sills producing thousands of hydrothermal vents on a scale far beyond anything seen today. Possible secondary sources of greenhouse gases were melting permafrost and sea floor methane hydrates, as a result of the initial volcanic warming.”
The realities of climate change are front-page news every day. Temperature records are being smashed. Wildfires are raging. There is no sign of
things going back to “normal”. If anything, they will only get worse.
Last year, when the planet was convulsing with the arrival of a pandemic, we pinned our hopes on technology – in the form of an mRNA vaccine – getting us out of our crisis. The vaccine was a technological intervention, injected into the arms of billions of people. Could we (should we?) look to technological solutions to our climate crisis, too?
Geoengineering refers to any number of ways that humans can change our climate through interventions. The two main types of geoengineering are carbon engineering, which aims to suck carbon out of the atmosphere, and solar engineering, which aims to reflect solar energy away from Earth.
“We’re in a climate crisis,” she tells me. “Mitigation isn’t going fast enough. Adaptation needs far more support than it’s getting. It’s clear that we need to remove some amount of carbon from the atmosphere.”
How much? “Hundreds of billions of gigatons,” Buck says. “We have emitted so much, and now we have so much legacy carbon. The challenge isn’t just cutting emissions.” The second challenge is “removing the carbon that’s up there. It’s this massive cleanup operation that we need to undertake this century.”
The idea of deliberately altering the climate can be frightening and distasteful, including to many environmentalists. But Buck argues that climate engineering is coming whether we like it or not. “If people on the environmental left – people who care about climate change – just reject all of these approaches out of hand, then we lose the ability to shape them, which would be a grave mistake,” she says.
The simplest form of geoengineering is the kind of carbon removal many of us learned about in school: planting trees. “Land-based solutions are really important, especially in the next decade or so, because they can be implemented quickly – and we know how to plant forests,” Buck says. She points to other kinds of land-based climate interventions that show promise. Changing agricultural practices can be used to store more carbon in the dirt. Other strategies include storing carbon in wetlands, ocean iron fertilization, or different approaches involving rock weathering.Advertisement
But land-based solutions, though a helpful beginning, probably won’t be enough, Buck says. To plant enough trees to soak up enough carbon to sufficiently cool our planet, we would have to fundamentally change the way we use land in ways that would make our economy and many of our lives unrecognizable. And there are other risks to relying too heavily on land-based techniques.
“A lot of land-based approaches are vulnerable to climate change itself,” Buck explains. “You don’t want a wildfire to wipe out these removals that you’ve been banking on, right?” Massive reforestation efforts could go up in smoke.
But land-based solutions are not the only option. Carbon removal can also be accomplished with industrial technologies. Buck points to a carbon mitigation strategy called geological carbon capture, which is already widely used to reduce the emissions of heavily polluting industries. “You could outfit, well, scrubbers basically, on a factory, and these collect carbon dioxide. Then you inject [the carbon] underground, into a cavern, and keep it there, under the rock, for a very long time. You keep monitoring it, to make sure it stays where you want it to be.”
There are risks to injecting large amounts of carbon into rock; Buck laments the under-regulated “wild west atmosphere” of fracking, which caused earthquakes in some parts of the US. But scientists have learned from that experience, and technologies exist to keep underground carbon in place. And new techniques may make geological carbon capture safer. “There’s a lot of new research about how to get carbon dioxide to turn into rock quicker once you inject it” underground, Buck says.
This is a carbon mitigation technique that has proved efficient in reducing emissions at an industrial scale, and it has been in use for decades, meaning that the safety and science of the technique are well understood. Buck’s hope is that this technology could advance and be used not just for mitigating carbon emissions, but for removing carbon.
“It becomes carbon removal” – as opposed to mitigation – “if you’re removing the carbon just from the ambient air,” Buck says. There are now machines that can “scrub” carbon out of the air; the carbon can then be transported and stored underground. Without these machines, the technique can also be used to create bioenergy, which involves “producing biomass” – say, a very carbon-dense type of plant – “and combusting it at a power plant, and separating out the carbon and storing it underground again”.Advertisementhttps://dd63591d5cb5fb92487208179aa5111c.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html
This strategy – using a spectrum of carbon-engineering techniques to inject carbon deep beneath rock – is the most effective and safest, Buck believes. But unless humanity gets its act together soon, we may forced to entertain much riskier climate mitigation strategies. “If we don’t remove carbon, and decarbonize, and reform how we use land, and rework our transportation systems, and change industrial systems fast enough,” Buck says, “then there’s the possibility that people will pitch the idea of solar geoengineering.”
Solar geoengineering is a kind of climate mitigation – thus far theoretical – that involves “blocking a fraction of incoming sunlight and sending it back out into space, which has a cooling effect”. Most solar-engineering techniques involve using special planes to inject gas into the stratosphere. The gas particles would reflect sunlight away, changing both the quantity and the quality of sunlight that reaches earth.
This kind of geoengineering would certainly cool the planet, at least for a while. But it would not solve the fundamental problem of too much carbon in the atmosphere. “It doesn’t get to the root,” says Buck. “It doesn’t remove emissions. It’s just a blanket of intentional pollution that cools things down.”
And solar geoengineering might create other problems, Buck says. What would a different kind of sunlight do to humankind, or to other living creatures? What would it do to agriculture, and our food supply? We don’t know. Would there be food shortages? Would the sky still be blue? We don’t have those answers, and solar geoengineering remains a risky proposition until we do.
How optimistic is Buck that humanity will attain a livable future without having to resort to solar geoengineering? More than I expected. The vision that she articulates is ambitious. It would require international cooperation and vast overhauls of infrastructure. It would also mean that the United States and other capitalist countries would have to reorient themselves to a more centrally planned economy, devoted less to maximizing growth than to minimizing carbon. It would mean overcoming vast political differences and competing incentives the world over in order to unite in global common cause.Advertisement
But Buck thinks that the incentives for cooperation in the existential climate intervention project are great enough to ensure at least some success.
“I do think that if people share a common goal, they might disagree about how to reach that goal, but maybe just having the common goal is enough,” she says.
The greatest cleanup operation of history – the cleanup of carbon in our atmosphere – may well happen within our lifetimes. And, if Buck is right, there is no better time to start it than right now.
Illustration showing the beginning of the Permian-Triassic mass extinction. 2020.Credit: PaleoFactory, Sapienza University of Rome for Jurikova et al., Nature Geoscience 2020.
A new paper claims to identify the cause of the Great Dying that occured nearly 252 million years ago.
During the worst mass extinction event ever, most of Earth’s life perished.
The study suggests a volcanic eruption in Siberia spread aerosolized nickel particles that harmed organisms on the planet.
Dinosaurs are the most infamous victims of a mass extinction event 66 million years ago. But an even worse extinction happened 251.9 million years ago.
Called the end-Permian mass extinction or the Great Dying, this most severe of extinction events wiped out about 90 percent of the planet’s marine species and 75 percent of terrestrial species. While scientists long have suspected it was initiated by volcanic eruptions in what is now Siberia, until now they haven’t been able to explain exactly how so many species died out.
A new paper published in Nature Communications lays out the case that nickel particles that became aerosolized as a result of eruptions in the Siberian Traps region became dispersed through the air and water and were the cause of the ensuing environmental catastrophe. The paper pinpoints huge Norilsk nickel sulfide ore deposits in the Tunguska Basin that “may have released voluminous nickel-rich volcanic gas and aerosols into the atmosphere” as the start of the chain of events that led to the mass extinction.
The study is based on analysis of nickel isotopes that came from late Permian sedimentary rocks gathered from the Buchanan Lake section in the Sverdrup Basin in the Canadian High Arctic. What’s notable about the rock samples is that they featured the lightest nickel isotope ratios ever measured, leading the scientists to conclude that the nickel came in the form of aerosolized particles from a volcano.
As the paper outlines, the only comparable nickel isotope values would be those from volcanic nickel sulfide deposits. The scientists write that of all the mechanisms that could result in such values, “the most convincing” explanation is that they got there as “voluminous Ni-rich aerosols” from the Siberian Traps large igneous province (STLIP).
The deadly effect of nickel particles
When the nickel got into the water, it wreaked havoc on the underwater ecosystem.
Co-author of the study, associate professor Laura Wasylenki of Northern Arizona University, explained that “nickel is an essential trace metal for many organisms, but an increase in nickel abundance would have driven an unusual surge in productivity of methanogens, microorganisms that produce methane gas. Increased methane would have been tremendously harmful to all oxygen-dependent life.” This would have affected living creatures in and out of the water. The professor believes their data offers direct evidence that links nickel-rich aerosols, changes to the ocean, and the mass extinction that followed. “Now we have evidence of a specific kill mechanism,” she added.https://f1bb792bf57395a28b571c77451c94cd.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html
NAU associate professor Laura Wasylenki.Credit: Northern Arizona University.
Other theories on the Great Dying
Previous studies have pointed to other effects of the Siberian volcanic eruptions that likely contributed to the extinction event, including an overall warming of the planet, release of toxic metals, and acidification of the oceans, which likely killed off a number of species quickly. Others died out as a result of the depleted oxygen levels in the water.
“This domino-like collapse of the inter-connected life-sustaining cycles and processes ultimately led to the observed catastrophic extent of mass extinction at the Permian-Triassic boundary,” said marine biogeochemist Hana Jurikova of the University of St. Andrews in the UK, who carried out a 2020 study on the end-Permian extinction. Her study looked at fossil shells from brachiopods in what is now the Southern Alps in Italy.
The most severe mass extinction event in the past 540 million years eliminated more than 90 percent of Earth’s marine species and 75 percent of terrestrial species. Although scientists had previously hypothesized that the end-Permian mass extinction, which took place 251 million years ago, was triggered by voluminous volcanic eruptions in a region of what is now Siberia, they were not able to explain the mechanism by which the eruptions resulted in the extinction of so many different species, both in the oceans and on land.
Associate professor Laura Wasylenki of Northern Arizona University’s School of Earth and Sustainability and Department of Chemistry and Biochemistry is co-author on a new paper in Nature Communications entitled, “Nickel isotopes link Siberian Traps aerosol particles to the end-Permian mass extinction,” in collaboration with Chinese, Canadian and Swiss scientists. The paper presents the results of nickel isotope analyses performed in Wasylenki’s lab on Late Permian sedimentary rocks collected in Arctic Canada. The samples have the lightest nickel isotope ratios ever measured in sedimentary rocks, and the only plausible explanation is that the nickel was sourced from the volcanic terrain, very likely carried by aerosol particles and deposited in the ocean, where it dramatically changed the chemistry of seawater and severely disrupted the marine ecosystem.
“The study results provide strong evidence that nickel-rich particles were aerosolized and dispersed widely, both through the atmosphere and into the ocean,” Wasylenki said. “Nickel is an essential trace metal for many organisms, but an increase in nickel abundance would have driven an unusual surge in productivity of methanogens, microorganisms that produce methane gas. Increased methane would have been tremendously harmful to all oxygen-dependent life.”
“Our data provide a direct link between global dispersion of Ni-rich aerosols, ocean chemistry changes and the mass extinction event,” Wasylenki said. “The data also demonstrate that environmental degradation likely began well before the extinction event—perhaps starting as early as 300,000 years before then. Prior to this study, the connection between Siberian Traps flood basalt volcanism, marine anoxia and mass extinction was rather vague, but now we have evidence of a specific kill mechanism. This finding demonstrates the power of nickel isotope analyses, which are relatively new, to solve long-standing problems in the geosciences.”
Wasylenki, who joined NAU in 2018, was formerly an igneous petrologist and then a specialist in calcite crystal growth and biomineralization. She now focuses on the use of metal stable isotope geochemistry to address geological, environmental and biological questions. Many of her recent and current projects have investigated metal isotope effects at solid-fluid interfaces, in particular during metal adsorption to oxyhydroxide mineral particles. This work has implications for ancient and modern geochemical cycles and environmental metal transport. Wasylenki’s lab group, named Systematic Experimental Study and Analysis of Metals in the Environment (SESAME Lab), focuses on two main research themes, the cycling of transition metals in modern and ancient oceans and the environmental transport of toxic heavy metals.
The planet has captured the fascination of Hollywood, the U.S. and China both landed rovers on its surface and Elon Musk, the head of SpaceX, recently announced that his company hopes to launch its next-generation rocket in 2022 from a platform in the Gulf of Mexico. His sights are set on Mars.
Other planets have become something of an afterthought. When was the last time you caught yourself thinking about Neptune? Pluto had the worst fate of all and in 2006 was downgraded to dwarf planet.
But NASA on Wednesday announced its intention to bring more attention to Venus, the second planet from the sun. The planet–which is one of the brightest objects in the night sky– is considered an “inferno-like world” but may have been “the first habitable world in the solar system, complete with an ocean and Earth-like climate.”
NASA said in a statement that the two missions to the planet will be part of its Discovery Program and will award about $500 million per mission for development. The voyages are expected to take place at the end of the decade.
One will study the planet’s atmosphere, which could shed light on whether the planet once had an ocean. The other mission will study the planet’s surface in hopes to learn “why it developed so differently than Earth.”
The U.S. and the former Soviet Union sent multiple spacecraft to Venus in the early days of space exploration. NASA’s Mariner 2 performed the first successful flyby in 1962, and the Soviets’ Venera 7 made the first successful landing in 1970.
In 1989, NASA used a space shuttle to send its Magellan spacecraft into orbit around Venus.
The European Space Agency put a spacecraft around Venus in 2006.
“It is astounding how little we know about Venus, but the combined results of these missions will tell us about the planet from the clouds in its sky through the volcanoes on its surface all the way down to its very core,” Tom Wagner, NASA’s Discovery Program scientist, said in the statement. “It will be as if we have rediscovered the planet.”
Life was trying, but it wasn’t working out. As the Late Devonian period dragged on, more and more living things died out, culminating in one of the greatest mass extinction events our planet has ever witnessed, approximately 359 million years ago.
The culprit responsible for so much death may not have been local, scientists say. In fact, it might not have even come from our Solar System.
Rather, a study published in August last year, led by astrophysicist Brian Fields from the University of Illinois Urbana-Champaign, suggests this great extinguisher of life on Earth could have been a distant and completely foreign phenomenon – a dying star, exploding far across the galaxy, many light-years away from our own remote planet.
Sometimes, mass die-offs like the Late Devonian extinction are thought to be triggered by exclusively terrestrial causes: a devastating volcanic eruption, for instance, which chokes the planet into lifelessness.
“We are citizens of a larger cosmos, and the cosmos intervenes in our lives – often imperceptibly, but sometimes ferociously.”
In their new work, Fields and his team explore the possibility that the dramatic decline in ozone levels coinciding with the Late Devonian extinction might not have been a result of volcanism or an episode of global warming.
Instead, they suggest it’s possible the biodiversity crisis exposed in the geological record could have been caused by astrophysical sources, speculating that the radiation effects from a supernova (or multiple) approximately 65 light-years from Earth may have been what depleted our planet’s ozone to such disastrous effect.
It may be the first time such an explanation has been put forward for the Late Devonian extinction, but scientists have long considered the potentially deadly repercussions of near-Earth supernovas in this kind of context.
Speculation that supernovas could trigger mass extinctions dates back to the 1950s. In more recent times, researchers have debated the estimated ‘kill distance’ of these explosive events (with estimates ranging between 25 to 50 light-years).
“Supernovae (SNe) are prompt sources of ionizing photons: extreme UV, X-rays, and gamma rays,” the researchers explain in their paper.
“Over longer timescales, the blast collides with surrounding gas, forming a shock that drives particle acceleration. In this way, SNe produce cosmic rays, that is, atomic nuclei accelerated to high energies. These charged particles are magnetically confined inside the SN remnant, and are expected to bathe Earth for ~100 ky [approximately 100,000 years].”
These cosmic rays, the researchers argue, could be strong enough to deplete the ozone layer and cause long-lasting radiation damage to life-forms inside Earth’s biosphere – which roughly parallels evidence of both loss of diversity and deformations in ancient plant spores found in the deep rock of the Devonian–Carboniferous boundary, laid approximately 359 million years ago.
Of course, it’s just a hypothesis for now. At present, we don’t have any evidence that can confirm a distant supernova (or supernovae) was the cause of the Late Devonian extinction. But we might be able to find something almost as good as proof.
In recent years, scientists examining the prospect of near-Earth supernovas as a basis for mass extinctions have been looking for traces of ancient radioactive isotopes that could only have been deposited on Earth via exploding stars.
In the context of the Late Devonian extinction, though, other isotopes would be strongly indicative of the extinction-by-supernova hypothesis put forward by Fields and his team: plutonium-244 and samarium-146.
“Neither of these isotopes occurs naturally on Earth today, and the only way they can get here is via cosmic explosions,” explained co-author and astronomy student Zhenghai Liu from the University of Illinois Urbana-Champaign.
In other words, if plutonium-244 and samarium-146 and can be found buried in the Devonian–Carboniferous boundary, the researchers say we’ll basically have our smoking gun: interstellar evidence that firmly implicates a dying star as the trigger behind one of Earth’s worst-ever die-offs.
And we’ll never look up at the skies in quite the same way again.