Archives par mot-clé : Extinction

better to know...?, climate and geology

Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon

by C.P. Fox et al., Dec 1, 2020 in PNAS

Significance

The end-Triassic mass extinction that occurred ∼202 Ma is one of the “Big Five” biotic crises of the Phanerozoic Eon. It is also accompanied by an organic carbon isotopic excursion that has long been interpreted as the result of a global-scale carbon-cycle disruption. Rather than being due to massive inputs of exogenous light carbon into the ocean–atmosphere system, the isotopic excursion is shown here to reflect regional sea-level change that caused a transition from a marine ecosystem to a less saline, shallow-water, microbial-mat environment and resultant changes in the sources of organic matter. The mass extinction that occurred slightly later, caused by abrupt injection of volcanogenic CO2, is accompanied by only modest changes in organic carbon isotopic composition.

Abstract

The negative organic carbon isotope excursion (CIE) associated with the end-Triassic mass extinction (ETE) is conventionally interpreted as the result of a massive flux of isotopically light carbon from exogenous sources into the atmosphere (e.g., thermogenic methane and/or methane clathrate dissociation linked to the Central Atlantic Magmatic Province [CAMP]). Instead, we demonstrate that at its type locality in the Bristol Channel Basin (UK), the CIE was caused by a marine to nonmarine transition resulting from an abrupt relative sea level drop. Our biomarker and compound-specific carbon isotopic data show that the emergence of microbial mats, influenced by an influx of fresh to brackish water, provided isotopically light carbon to both organic and inorganic carbon pools in centimeter-scale water depths, leading to the negative CIE. Thus, the iconic CIE and the disappearance of marine biota at the type locality are the result of local environmental change and do not mark either the global extinction event or input of exogenous light carbon into the atmosphere. Instead, the main extinction phase occurs slightly later in marine strata, where it is coeval with terrestrial extinctions and ocean acidification driven by CAMP-induced increases in PCO2; these effects should not be conflated with the CIE. An abrupt sea-level fall observed in the Central European basins reflects the tectonic consequences of the initial CAMP emplacement, with broad implications for all extinction events related to large igneous provinces.

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climate and geology

Permian–Triassic mass extinction pulses driven by major marine carbon cycle perturbations

by Jurikova, H. et al., Oct 19, 2020 in NatureGeoscience

Abstract

The Permian/Triassic boundary approximately 251.9 million years ago marked the most severe environmental crisis identified in the geological record, which dictated the onwards course for the evolution of life. Magmatism from Siberian Traps is thought to have played an important role, but the causational trigger and its feedbacks are yet to be fully understood. Here we present a new boron-isotope-derived seawater pH record from fossil brachiopod shells deposited on the Tethys shelf that demonstrates a substantial decline in seawater pH coeval with the onset of the mass extinction in the latest Permian. Combined with carbon isotope data, our results are integrated in a geochemical model that resolves the carbon cycle dynamics as well as the ocean redox conditions and nitrogen isotope turnover. We find that the initial ocean acidification was intimately linked to a large pulse of carbon degassing from the Siberian sill intrusions. We unravel the consequences of the greenhouse effect on the marine environment, and show how elevated sea surface temperatures, export production and nutrient input driven by increased rates of chemical weathering gave rise to widespread deoxygenation and sporadic sulfide poisoning of the oceans in the earliest Triassic. Our findings enable us to assemble a consistent biogeochemical reconstruction of the mechanisms that resulted in the largest Phanerozoic mass extinction.

climate and geology

A New Mass Extinction Event Has Been Discovered, And It Triggered The Rise of Dinosaurs

by M. Benton, Sep 25, 2020 in ScienceAlert

Huge volcanic eruptions 233 million years ago pumped carbon dioxide, methane, and water vapour into the atmosphere. This series of violent explosions, on what we now know as the west coast of Canada, led to massive global warming.

Our new research has revealed that this was a planet-changing mass extinction event that killed off many of the dominant tetrapods and heralded the dawn of the dinosaurs.

The best known mass extinction happened at the end of the Cretaceous period, 66 million years ago. This is when dinosaurs, pterosaurs, marine reptiles and ammonites all died out.

This event was caused primarily by the impact of a giant asteroid that blacked out the light of the sun and caused darkness and freezing, followed by other massive perturbations of the oceans and atmosphere.

Geologists and palaeontologists agree on a roster of five such events, of which the end-Cretaceous mass extinction was the last. So our new discovery of a previously unknown mass extinction might seem unexpected.

And yet this event, termed the Carnian Pluvial Episode (CPE), seems to have killed as many species as the giant asteroid did. Ecosystems on land and sea were profoundly changed, as the planet got warmer and drier.

On land, this triggered profound changes in plants and herbivores. In turn, with the decline of the dominant plant-eating tetrapods, such as rhynchosaurs and dicynodonts, the dinosaurs were given their chance.

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climate-debate

New evidence that an extraterrestrial collision 12,800 years ago triggered an abrupt climate change for Earth

by C. Rotter, July 27, 2020 in WUWT

Christopher R. Moore, University of South Carolina

What kicked off the Earth’s rapid cooling 12,800 years ago?

In the space of just a couple of years, average temperatures abruptly dropped, resulting in temperatures as much as 14 degrees Fahrenheit cooler in some regions of the Northern Hemisphere. If a drop like that happened today, it would mean the average temperature of Miami Beach would quickly change to that of current Montreal, Canada. Layers of ice in Greenland show that this cool period in the Northern Hemisphere lasted about 1,400 years.

This climate event, called the Younger Dryas by scientists, marked the beginning of a decline in ice-age megafauna, such as mammoth and mastodon, eventually leading to extinction of more than 35 genera of animals across North America. Although disputed, some research suggests that Younger Dryas environmental changes led to a population decline among the Native Americans known for their distinctive Clovis spear points.

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A collision from space would leave its mark on Earth. Vadim Sadovski/Shutterstock.com

What would an Earth impact leave behind?

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Biodiversity

Actualité Débats Kervasdoué – Quelques vérités sur la biodiversité

by Jean de Kersvasdoué, 6 janvier 2020 in LePoint

Derrière une bataille de chiffres alarmistes se cachent des biais statistiques et des questions de fond sur ce que l’on entend par « biodiversité ».

 

À l’occasion des vœux à la nation, le président de la République, Emmanuel Macron, a déclaré vouloir « œuvrer en faveur de la biodiversité ». Cet objectif est noble pour de multiples raisons et, notamment, parce que certaines espèces de grands mammifères sont menacées mais aussi quelques plantes et animaux de la métropole. Les grands singes, le rhinocéros noir sont en voie d’extinction. En ce qui concerne ce dernier, selon l’UICN, il n’en restait que 5 055 têtes en 2012. Or ces animaux continuent d’être chassés pour les prétendues valeurs aphrodisiaques de leur corne revendue 40 000 dollars le kilo à Shanghai. On comprend pourquoi les braconniers les recherchent et trouvent des complicités chez des gardes mal payés qui, en outre, risquent leur vie en s’opposant aux auteurs de ces regrettables massacres. A contrario, certaines espèces que l’on croyait disparues à l’état sauvage renaissent, comme la perruche de l’île Maurice ou l’oryx d’Arabie. Toutefois, en la matière, les bonnes nouvelles sont rares et la liste des espèces menacées à l’état sauvage s’allonge dans le monde du fait de la croissance de la population de la planète et de la mise en culture d’espaces jusque-là occupés par la forêt. Des écosystèmes disparaissent et avec eux végétaux et animaux qui y vivaient. Si donc préserver ces espèces est un objectif louable, il concerne rarement la France à l’exception des forêts de Guyane, mais il la touche cependant.

En France métropolitaine, le nombre de plantes supérieures, à fleurs, dites « phanérogames », donc hors champignons, mousses, fougères, lichens, algues, etc., du territoire métropolitain est d’environ 5 000 espèces sauvages ou cultivées. Pour les vertébrés, on y trouve de l’ordre de 40 poissons d’eau douce, 40 amphibiens (ou batraciens), 40 reptiles (serpents, lézards, tortues), 400 oiseaux en comptant des migrateurs qui ne nichent pas sur le territoire national, et 80 mammifères. Au total : environ 600 vertébrés. Donc, en additionnant les végétaux supérieurs et les animaux supérieurs, au sens de l’évolution darwinienne, 5 600 espèces en France. La très grande majorité n’est pas menacée et les espèces qui sont prétendues l’être (1) ne le sont pas toujours.

L’exagération est la règle

Sur les six espèces décrites comme pouvant disparaître, il y a une plante (l’orchis couleur de lait) et cinq animaux (la sterne de l’Arctique, le lynx boréal, la grenouille des champs, la tortue d’Hermann et l’anguille). On trouve l’orchis couleur de lait dans le sud de la France et en Corse, il est difficile de mesurer la réalité de la menace qui pèse sur elle (2), faute de méthode de recensement. En ce qui concerne les espèces animales, deux ne sont en rien menacées (la sterne et le lynx boréal). Si la grenouille des champs l’est dans notre pays, elle ne l’est pas ailleurs en Europe à l’exception de la grenouille des Pyrénées. Restent la tortue d’Hermann et l’anguille européenne.

La tortue d’Hermann est la seule espèce de tortue terrestre de France. Elle est présente dans le Var et en Corse. Son habitat est détruit par les feux de forêt, le débroussaillage, le morcellement des parcelles, les routes et l’habitat pavillonnaire. Quant à l’anguille européenne (Anguilla anguilla), autrefois abondante dans tous les cours d’eau et les zones humides (lacs, étangs, marais, mares, fossés), son déclin se constate depuis 40 ans. Cette régression provient de plusieurs facteurs : divers contaminants toxiques (pesticides organochlorés bio-accumulés par l’anguille), la surpêche des civelles et des adultes de plus en plus appréciés, le braconnage, les obstacles sur la route des alevins et une augmentation du taux de parasitisme (par le nématode Anguillicola crassus) qui perturbe la migration marine des adultes. Un règlement européen (R(CE) no 1100/2007) impose des mesures de connaissance et de protection et de gestion de l’anguille et semble porter des fruits.

Continuer la lecture de Actualité Débats Kervasdoué – Quelques vérités sur la biodiversité →

only geology

Oxygen depletion in ancient oceans caused major mass extinction

by Florida State University, August. 30, 2019 in ScienceDaily/fromGeology

Late in the prehistoric Silurian Period, around 420 million years ago, a devastating mass extinction event wiped 23 percent of all marine animals from the face of the planet.

For years, scientists struggled to connect a mechanism to this mass extinction, one of the 10 most dramatic ever recorded in Earth’s history. Now, researchers from Florida State University have confirmed that this event, referred to by scientists as the Lau/Kozlowskii extinction, was triggered by an all-too-familiar culprit: rapid and widespread depletion of oxygen in the global oceans.

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better to know...?, Biodiversity

Celebrating America’s Environmental Stewardship

by Jim Steele, July 10, 209 in WUWT

What’s Natural?

Celebrating America’s Environmental Stewardship

I resent the one-sided mis-characterization of humanity as “destroyers of our environment”. Humans certainly had negative impacts on most ecosystems. However, in contrast to a recent United Nations report insinuating we are threatening one million species with extinction, humans have been working hard to restore nature and prevent further extinctions. Most endangered species are still staggering from disruptions initiated centuries ago. But now humans are correcting past mistakes.

Islands have been extinction hotspots. Sixty-one percent of all known extinctions have occurred on islands and 37% of today’s critically endangered species are found only on islands. The main driver of island extinctions has been purposeful or unintentional introductions of alien species. Introduced species are implicated in 81% of all island extinctions. With no natural predators, Island species did not evolve needed behaviors to avoid introduced rats, cats and stoats. Researchers now suggest eradication of rats and other introduced mammals could prevent the extinction of up to 75% of threatened island birds, reptiles and mammals.

 

 

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Biodiversity

Will Climate Change Drive a Million Species Extinct?

by Vijay Jayaraj, June 3, 2019 Townhall

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A million species threatened by “climate change”? Well, climate change as defined by the UN Framework Convention on Climate Change (“a change of climate that is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods”) isn’t likely to bring about any warming exceeding that of the warm periods mentioned above.

Which of course means it’s not likely to drive millions of species extinct. In fact, it will be a miracle if the gradual change in climate causes any alarming extinctions at all.

Only illegal hunting and habitat destruction (despite protection by governments) continue to threaten endangered species. Even in the worst case, they won’t cause species extinctions in the millions.

Vijay Jayaraj (M.Sc., Environmental Science, University of East Anglia, England), Research Associate for Developing Countries for the Cornwall Alliance for the Stewardship of Creation, lives in Bangalore, India.

Biodiversity, climate-debate

Recent Studies Indicate Species Extinctions Decline With Warming – Mass Extinction Events Due To COOLING

by K. Richard, May 16, 2019 in NoTricksZone

In the past it has been widely reported that high and abruptly changing CO2 concentrations led to climate conditions that were “too hot for complex life to survive” on the planet.
More recently, though, scientists have determined that the opposite may have been true: mass extinction events occurred during periods of global cooling, expansive ice sheet growth, and marine-habitat-destroying sea level drops of more than 100 meters.
In fact, of the 5 previous mass extinctions, volcanism-induced glaciation is thought to be responsible for the 1st, 3rd, and 4th events, with the 2nd unknown and the 5th from an aseteroid impact.  None of these explanations have ties to CO2 concentrations or sudden warming.

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Image Sources: Loehle & Eschenbach (2012), BBC, Wrightstone, 2019
Biodiversity

The UN’s Extinction Warning Doesn’t Add Up (Except On The BBC)

by Toby Young, May 9, 2019 in ClimateChangeDispatch

Anyone watching the BBC’s News at Ten on Monday would have been surprised to learn that economic growth poses a dire threat to the future of life on this planet.

We’re used to hearing this from climate change campaigners, but I’ve always taken such claims with a pinch of salt, suspecting that the anti-capitalist left is distorting the evidence. Apparently not.

‘One million species at risk of imminent extinction according to a major UN report,’ intoned the BBC. ‘It says the Earth’s ecosystems are being destroyed by the relentless pursuit of economic growth.’

So does this mean the Extinction Rebellion protestors are right?

I decided to do some digging to see if one million species really do ‘face extinction in the next few decades’, as the BBC put it.

That claim is based on a report by the UN’s Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), but it hasn’t been published yet.

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Biodiversity

Nature crisis: Humans ‘threaten 1m species with extinction’-BBC

by P. Homewood, May 7, 2019 in NotaLotofPeopleKnowThat

The BBC has just reported on the newly published Summary for Policy Makers of the as yet unpublished UN 1800 page global assessment of nature compiled by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). The two day old ‘climate crisis’, so recently [not] declared by the British government has already been knocked off the top spot as far as existential crises are concerned and is now officially languishing in 3rd place, in the Second Division. Land use change is now Premier Division. However, unlike action on the ‘climate crisis’, which has become a $1.5 trillion industry, action on land use change has been negligible to non-existent. Even hunting (legal and non-legal) and the direct exploitation of wildlife is one division above climate change in terms of the threat to biodiversity. Bugger all has been done to address these threats too, relatively speaking, during the last three decades, whereas trillions has been thrown at ineffective, and socially, economically and environmentally damaging attempts to limit global warming to 2C (and latterly 1.5C). I warned about this 3 years ago.

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Biodiversity

IPCC Clone Predicts Doom

by Donna Laframboise, May 6, 2019 in BigPictureNews

Here we ago again. For some time, I’ve warned that the Intergovernmental Panel on Climate Change (IPCC) is a template, that the United Nations is up to the same tricks elsewhere.

Today, in Paris, an IPCC clone known as the IPBES – the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services – will announce the completion of an 1,800-page report.

Jonathan Watts, the UK Guardian‘s global environment editor, has already told us everything we need to know about this ‘IPCC for Nature‘.

Under the headline Biodiversity crisis is about to put humanity at risk, UN scientists to warn, he insists this report was written by “The world’s leading scientists.” Funny, that’s how compliant, gullible journalists described IPCC personnel. For years and years. Until I began to notice that some of those involved were graduate students in their 20s.

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better to know...?, Biodiversity

WHAT? NO SIXTH EXTINCTION?

by Andrew Montford, April 23, 2019 in GWPF

Extinction Rebellion seem to be everywhere at the moment. And everywhere their story is the same. We are in the middle of a climate catastrophe. As the Huffington Post put it,

Human-caused climate change is driving sea-level rise, drought, extreme weather and a biodiversity crisis that scientists have declared Earth’s sixth mass extinction event. As many as 150 species die off each day.

Scary eh? Surely that’s enough to justify the odd street protest?

It was therefore interesting to see read some remarks from Richard Betts today. Professor Betts is the head of climate impacts at the Met Office, so his views in this area carry a certain amount of weight. Asked what he thought were the top three negative impacts of climate change that have “absolutely started”, he replied:

  • Sea level rise
  • Increasing risk of high temperatures
  • Changes in phenology and distribution for numerous species

This left me agog. There was nothing about drought or hurricanes or any of the other manifestations of extreme weather that are said to be afflicting us; nothing about floods, or typhoons, or desertification or crashing crop yields or climate refugees, mass extinctions, skydiving walruses and any of the thousand and one tall tales that climate activists spin and the media faithfully repeat every day. The contrast between this take on currently observed negative impacts and David Attenborough’s risible Climate Change: the Facts programme last week is startling. The take home message is that most of what the “national treasure” told viewers about climate change was grubby insinuation rather than fact: less to do with science than with the BBC’s ongoing eco-campaign.

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only geology

New evidence suggests volcanoes caused biggest mass extinction ever

by University of Cincinnati, April 15, 2019 in ScienceDaily from Nature

Mercury found in ancient rock around the world supports theory that eruptions caused ‘Great Dying’ 252 million years ago.

Researchers say mercury buried in ancient rock provides the strongest evidence yet that volcanoes caused the biggest mass extinction in the history of the Earth.

The extinction 252 million years ago was so dramatic and widespread that scientists call it “the Great Dying.” The catastrophe killed off more than 95 percent of life on Earth over the course of hundreds of thousands of years.

Paleontologists with the University of Cincinnati and the China University of Geosciences said they found a spike in mercury in the geologic record at nearly a dozen sites around the world, which provides persuasive evidence that volcanic eruptions were to blame for this global cataclysm.

The study was published this month in the journal Nature Communications.

The eruptions ignited vast deposits of coal, releasing mercury vapor high into the atmosphere. Eventually, it rained down into the marine sediment around the planet, creating an elemental signature of a catastrophe that would herald the age of dinosaurs.

“Volcanic activities, including emissions of volcanic gases and combustion of organic matter, released abundant mercury to the surface of the Earth,” said lead author Jun Shen, an associate professor at the China University of Geosciences.

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climate and geology, only geology

Do volcanoes or an asteroid deserve blame for dinosaur extinction?

by Univ. of California – Berkeley, February 21, 2019 in ScienceDaily

Based on new data published today in the journal Science, it seems increasingly likely that an asteroid or comet impact 66 million years ago reignited massive volcanic eruptions in India, half a world away from the impact site in the Caribbean Sea.

But it leaves unclear to what degree the two catastrophes contributed to the near-simultaneous mass extinction that killed off the dinosaurs and many other forms of life.

The research sheds light on huge lava flows that have erupted periodically over Earth’s history, and how they have affected the atmosphere and altered the course of life on the planet.

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better to know...?, climate and geology

Human ancestors not to blame for ancient mammal extinctions in Africa

by University of Utah, November23, 2018 in ScienceDaily

New research disputes a long-held view that our earliest tool-bearing ancestors contributed to the demise of large mammals in Africa over the last several million years. Instead, the researchers argue that long-term environmental change drove the extinctions, mainly in the form of grassland expansion likely caused by falling atmospheric carbon dioxide (CO2) levels.

The study is published today in the journal Science.

“Despite decades of literature asserting that early hominins impacted ancient African faunas, there have been few attempts to actually test this scenario or to explore alternatives,” Faith says. “We think our study is a major step towards understanding the depth of anthropogenic impacts on large mammal communities, and provides a convincing counter-argument to these long-held views about our early ancestors.”

To test for ancient hominin impacts, the researchers compiled a seven-million-year record of herbivore extinctions in eastern Africa, focusing on the very largest species, the so-called ‘megaherbivores’ (species over 2,000 lbs.) Though only five megaherbivores exist in Africa today, there was a much greater diversity in the past. For example, three-million-year-old ‘Lucy’ (Australopithecus afarensis) shared her woodland landscape with three giraffes, two rhinos, a hippo, and four elephant-like species at Hadar, Ethiopia.

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See also here

only geology

Geologists uncover new clues about largest mass extinction ever

by University of Tennessee at Knoxville, August 27, 2018 in ScienceDaily from Nature.

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Through the analysis of samples, Broadley and his team tried to determine the composition of the lithosphere. They found that before the Siberian Flood Basalts took place, the Siberian lithosphere was heavily loaded with chlorine, bromine, and iodine, all chemical elements from the halogen group. However, these elements seem to have disappeared after the volcanic eruption.

“We concluded that the large reservoir of halogens that was stored in the Siberian lithosphere was sent into the earth’s atmosphere during the volcanic explosion, effectively destroying the ozone layer at the time and contributing to the mass extinction,” Broadley said.

biology+acidification

The sixth mass genesis? New species are coming into existence faster than ever thanks to humans

by Prof. Chris D. Thomas, July 10, 2017 in TheConversation

Animals and plants are seemingly disappearing faster than at any time since the dinosaurs died out, 66m years ago. The death knell tolls for life on Earth. Rhinos will soon be gone unless we defend them, Mexico’s final few Vaquita porpoises are drowning in fishing nets, and in America, Franklin trees survive only in parks and gardens.

Yet the survivors are taking advantage of new opportunities created by humans. Many are spreading into new parts of the world, adapting to new conditions, and even evolving into new species … (…)

only geology

What caused the mass extinction of Earth’s first animals?

by Arizona State University, June 27, 2018 in ScienceDaily

Scientists have argued for decades over what may have caused this mass extinction, during what is called the “Ediacaran-Cambrian transition.” Some think that a steep decline in dissolved oxygen in the ocean was responsible. Others hypothesize that these early animals were progressively replaced by newly evolved animals.

The precise cause has remained elusive, in part because so little is known about the chemistry of Earth’s oceans that long ago.

A research team, led by scientists from Arizona State University and funded by NASA and the National Science Foundation, is helping to unravel this mystery and understand why this extinction event happened, what it can tell us about our origins, and how the world as we know it came to be. The study, published in Science Advances, was led by ASU School of Earth and Space Exploration graduate student Feifei Zhang, under the direction of faculty member Ariel Anbar and staff scientist Stephen Romaniello. (…)

only geology

When the dinosaurs died, so did forests — and tree-dwelling birds

By Field Museum, May 24, 2018 in ScienceDaily (CurrentBiology)

Sixty-six million years ago, the world burned. An asteroid crashed to Earth with a force one million times larger than the largest atomic bomb, causing the extinction of the dinosaurs. But dinosaurs weren’t the only ones that got hit hard — in a new study, scientists learned that the planet’s forests were decimated, leading to the extinction of tree-dwelling birds.

climate-debate, sciences-general

Invisible Scientific Debates Accomplish Nothing

by Donna Laframboise, April 23, 2018 in ClimateChangeDispatch

SPOTLIGHT: After the Intergovernmental Panel on Climate Change (IPCC) report was released in 2007, its dramatic findings of species extinction were repeatedly emphasized by chairman Rajendra Pachauri.

BIG PICTURE: When it examined the question of species extinction, the 2007 IPCC report relied heavily on a single piece of research – a Nature cover storypublished early in 2004. Written by Chris Thomas and 18 others, this was the source of Pachauri’s claim that climate change threatened 20 to 30% of the world’s species.

only geology

Studying oxygen, scientists discover clues to recovery from mass extinction

by Arizona State University, April  17, 2018 in ScienceDaily

About 252 million years ago, more than 90 percent of all animal life on Earth went extinct. This event, called the “Permian-Triassic mass extinction,” represents the greatest catastrophe in the history of life on Earth. Ecosystems took nearly five million years to recover and many aspects of the event remain a mystery.

A research team, led by scientists from Arizona State University and funded by NASA and the National Science Foundation, is helping to understand why this extinction event happened and why it took life so long to recover. The study, published in Science Advances, was led by ASU School of Earth and Space Exploration graduate student Feifei Zhang, with direction from school faculty member Ariel Anbar.

climate and geology

Extinction and global warming 250 million years ago

by U. of Bristol, January 10, 2018 in A Watts, WUWT

One of the key effects of the end-Permian mass extinction, 252 million years ago, was rapid heating of tropical waters and atmospheres.

How this affected life on land has been uncertain until now.

In a new study published today, Dr Massimo Bernardi and Professor Mike Benton from the School of Earth Sciences at the University of Bristol show how early reptiles were expelled from the tropics.

climate and geology

Volcanic eruptions drove ancient global warming event

by Marcus Gutjah et al., August 30,  2017 in PhysOrg

A natural global warming event that took place 56 million years ago was triggered almost entirely by volcanic eruptions that occurred as Greenland separated from Europe during the opening of the North Atlantic Ocean,
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The amount of carbon released during this time was vast—more than 30 times larger than all the fossil fuels burned to date and equivalent to all the current conventional and unconventional fossil fuel reserves we could feasibly ever extract.” Ridgwell said.

An unexpected finding was that enhanced organic matter burial was important in ultimately sequestering the released carbon and accelerating the recovery of the Earth’s ecosystem without massive extinctions.

See also here