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nanning

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Re: The Holocene Extinction
« Reply #450 on: January 30, 2020, 02:02:21 PM »
^^
Thank you for that gerontocrat.



Shamen, spirits, survival: how Claudia Andujar fought for the Yanomami tribe

https://www.theguardian.com/artanddesign/2020/jan/29/claudia-andujar-photography-yanomami-brazil-jair-bolsonaro
  by Oliver Basciano

An interesting article describing a period when Claudia, a photographer, lived for some time with the tribe. Beautiful photo's.


In the context of upthread discussion, these excerpts caught my attention:


"Claudia took her time to get to know us; she slept in our shabono,” he says, referring to the ring-shaped wooden buildings that the Yanomami live in communally."

"Elsewhere, the Yanomami are shown sympathetically, romanticised perhaps, with no hint to what some conservative anthropologists claim to be a violent culture inherent to the tribe."

"Traditionally, Yanomami do not give each other names, referring only to their relationships with one another."





I post this here because three days ago, Terry mentioned civilisation behaviour by the pre-contacted tribe from the article above:

https://forum.arctic-sea-ice.net/index.php/topic,2305.msg246552.html#msg246552

This Guardian article gives me another and very different and non-conservative view.
It is easy to try to counter my research with such random unscientific conservative examples. Then it's up to me to find out what's going on without a having a link. Sorry, but I find that tiresome and unfair.

I don't need and I don't want to explain my research to people who are not interested.
I had thought that losing distorted views is very important to people who want to see the truth. Apparently not. This truth-loving goes not very deep in my view. Especially where the truth implies that your culture is very bad and insane. That's a truth that intelligent truth-people don't want to see it seems.
"It is preoccupation with possessions, more than anything else, that prevents us from living freely and nobly" - Bertrand Russell
"It is preoccupation with what other people from your groups think of you, that prevents you from living freely and nobly" - Nanning
Why do you keep accumulating stuff?

kassy

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Re: The Holocene Extinction
« Reply #451 on: January 31, 2020, 11:08:22 AM »
Warming Swiss rivers threaten fish stocks

Swiss rivers are warming as the volume of glacial meltwater decreases, according to a study. Researchers warn that the phenomenon is threatening fish stocks and is likely to get worse in the coming years.

The report, published in the journal Hydrology and Earth System Sciencesexternal link, measured both the melting of glaciers over the course of 40 years and the temperature of rivers they discharge into. They found that rivers had warmed by an average of 0.33°C every decade since 1980, and by 0.37°C per decade over the past 20 years.

They also observed a 3% average decrease in meltwater discharge over the past 40 years as glaciers shrink. The trend has accelerated in the past two decades with a 10% decrease in glacial meltwater discharge into rivers.

...

“We were surprised to find that Swiss rivers are warming at 95% of the rate of the surrounding air,” he saidexternal link. “The conventional wisdom was that the melting of snow and glaciers and the fact that this water then flowed into lakes were counteracting the effect of warmer air on the Swiss plateau. That’s no longer the case.”

Thresholds
“There’s a commonly held belief that one or two degrees of warming won’t make much difference,” he added.

“The truth is that these ecosystems aren’t resilient enough to cope when the temperature exceeds certain thresholds several times a year, especially in summer. A few degrees’ warming means we’re going to see those thresholds surpassed much more often.”

https://www.swissinfo.ch/eng/sci-tech/shrinking-glaciers_warming-swiss-rivers-threaten-fish-stocks/45530254

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kassy

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Re: The Holocene Extinction
« Reply #452 on: February 02, 2020, 10:15:54 PM »
Koalas found dead on Australia logging plantation

Dozens of koalas have been found dead or injured at a timber plantation in the Australian state of Victoria, sparking an investigation by officials.

Blue gum trees - an important koala habitat - were harvested from the plantation in December, leaving only a few isolated stands of trees.

Some koalas had starved to death in the remaining trees. Others were apparently killed by bulldozers.

About 80 surviving koalas have been removed and are being cared for.

The deaths come after tens of thousands of koalas were killed in the bushfires that have ravaged Australia. The marsupial is listed as "vulnerable" by Australia's Environment Ministry.

'Australia should be ashamed'
After the plantation was logged in December, reports of hundreds of starving koalas came in, environmental group Friends of the Earth Australia said.

"People apparently witnessed the bulldozing of many dead koalas into slash piles," it said.

The Department of Environment, Land, Water and Planning said it was prepared to prosecute over the incident.

more sad on:
https://www.bbc.com/news/world-australia-51346637
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Florifulgurator

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Re: The Holocene Extinction
« Reply #453 on: February 05, 2020, 03:29:45 AM »
Re: nerve gas

Seek medical help.

sidd


Damn good advice!
I inhaled a huge quantity of R-12 that had passed through an Oxy-Acetylene flame. The phosgene, a WW1 nerve gas, left me unable to scale a ladder for >a week.
The doctors couldn't do much about it, but they did make me very conscious of the danger the next times I was welding R-12 systems.


It's not impossible that it is responsible for my present problems, though the doctors think not.


Stay Healthy
Terry

There are easier ways to get a dose of phosgene: Burn old impregnated wood (e.g. with Lindane).
Google image search on my avatar image gives "wood". In fact it is the lower part of David Hilbert's tombstone.

gerontocrat

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Re: The Holocene Extinction
« Reply #454 on: February 07, 2020, 09:28:15 PM »
A report that at last highlights the multiplier effect of interlinked environmental emergencies

Link to download here - https://futureearth.org/publications/our-future-on-earth/

Extract from guardian article below.

Humanity under threat from perfect storm of crises – study
Climate, extreme weather, biodiversity, food and water crises could lead to ‘systemic collapse’
Quote
The world is facing a series of interlinked emergencies that are threatening the existence of humans, because the sum of the effects of the crises is much greater than their individual impacts, according to a new global study.

Climate breakdown and extreme weather, species loss, water scarcity and a food production crisis are all serious in themselves, but the combination of all five together is amplifying the risks of each, creating a perfect storm that threatens to engulf humanity unless swift action is taken.

The links among the crises are clear in many cases, but the methods the world has chosen to try to solve them do not take account of these connecting factors. For instance, extreme heatwaves can add to global heating, because they release vast amounts of stored carbon from affected ecosystems, in a feedback loop. It has been seen clearly in the Australian bushfires, which are already contributing significantly to the store of carbon in the atmosphere.

The links do not stop there: as the heatwaves damage natural ecosystems, killing off wildlife and flora, they also lead to greater water scarcity, and in turn damage agriculture. These combined effects exacerbate the harm done to people struggling with food and water shortages, in a vicious cycle.

Faced with these crises in nature individually, it could be possible to fix the problems causing them. But confronted with multiple interlinked emergencies that in combination amplify one another’s impacts, people are facing unprecedented dangers and many communities cannot cope.

The report, which took the form of a survey of 222 leading scientists from 52 countries, conducted by the international sustainability network Future Earth, found that the responses to these emergencies by governments, civil society, business and institutions did not recognise their interlinked nature. Trying to solve the problems individually, without taking account of the “cascading” impacts, was likely to be ineffective, the scientists said.

More than a third of the scientists surveyed said the five crisis types would worsen one another “in ways that might cascade to create global systemic collapse”.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
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kassy

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Re: The Holocene Extinction
« Reply #455 on: February 11, 2020, 08:26:55 PM »
Some background stuff:

Here is some recent stuff...

Himalayan glacier shows evidence of start of Industrial Revolution

...

Dasuopu -- at 7,200 meters or 23,600 feet above sea level -- is the highest-altitude site in the world where scientists have obtained a climate record from an ice core. Dasuopu is located on Shishapangma, one of the world's 14 tallest mountains, which are all located in the Himalayas.

For this study, the research team analyzed one core taken from Dasuopu in 1997 for 23 trace metals.

The ice cores operate as a sort of timeline, and show new ice forming in layers on the glacier over time. It is possible for researchers to tell almost the precise year a layer of the glacier formed because of environmental clues like snowfall or other known natural or human-made disasters. The ice the researchers evaluated formed between 1499 and 1992, the team determined. Their goal was to see whether human activity had affected the ice in any way, and, if so, when the effects had begun.

Their analysis showed it had: The team found higher-than-natural levels of a number of toxic metals, including cadmium, chromium, nickel and zinc, in the ice starting at around 1780 -- the very start of the Industrial Revolution in the United Kingdom. Those metals are all byproducts of burning coal, a key part of industry at the end of the 18th century and throughout the 19th and 20th centuries.

The researchers found that those metals were likely transported by winter winds, which travel around the globe from west to east.

They also believe it is possible that some of the metals, most notably zinc, came from large-scale forest fires, including those used in the 1800s and 1900s to clear trees to make way for farms.

"What happens is at that time, in addition to the Industrial Revolution, the human population exploded and expanded," Gabrielli said. "And so there was a greater need for agricultural fields -- and, typically, the way they got new fields was to burn forests."

...

https://www.sciencedaily.com/releases/2020/02/200210153343.htm
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TerryM

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Re: The Holocene Extinction
« Reply #456 on: February 11, 2020, 09:42:53 PM »
<snipped>
"What happens is at that time, in addition to the Industrial Revolution, the human population exploded and expanded," Gabrielli said. "And so there was a greater need for agricultural fields -- and, typically, the way they got new fields was to burn forests."

...

https://www.sciencedaily.com/releases/2020/02/200210153343.htm
Today there is a "greater need" for Giga Factories.


Today we'd clear cut the forest, but only after assuring the community that the ants, insects and fledgling birds have been lovingly removed from their nests - and promising that we'll plant 3 times as many trees as we've destroyed. :)


In half a century these seedlings (should they survive) could be sequestering more carbon than the forest we removed, perhaps in a century they'll have made up for the lean years and perhaps by the 22nd century we'll look back and wonder why none of the "brown fields" were available for restoration.
Terry


kassy

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Re: The Holocene Extinction
« Reply #457 on: February 12, 2020, 03:10:15 PM »
And so much dies with it...the small critters , the fungal networks. All mostly invisible stuff providing free services to the planet until you kill it.

Penguins starving as Antarctica warms: Drones help count the losses

...

Liu, a doctoral student of robotics at Northeastern, is part of a scientific expedition that has sailed on the Greenpeace vessel Esperanza from Ushuaia, on the Tierra del Fuego archipelago of Argentina, to Elephant Island.

Scientists suspect that the population of the chinstrap penguins that inhabit the island is dwindling. Using drones and machine learning algorithms to speed up the process of counting penguins in large and inaccessible areas, the team is seeking to measure the decline.

...

Changes within the environment around the peninsula's shores might mean that populations of krill, the small crustaceans that are the chinstrap's favorite food, are moving southward, toward colder locations beyond the reach of chinstrap penguins on Elephant Island.

....

The chinstraps haven't been counted on Elephant Island since 1971. Now, the team's data suggest that over half of that population is gone. The observations are similar to the falling numbers of chinstrap penguins in other parts of the continent.

The story is different when the team counts the gentoo, another penguin species that lives on the island. Gentoo numbers are on the rise, and that is no surprise. Scientists believe that warmer temperatures allow gentoo penguins, which feed on more than just krill, to thrive farther south.



https://phys.org/news/2020-02-penguins-starving-antarctica-drones-losses.html

Article is worth a read, i just quoted the penguin extinction related bits here.

Interesting place to end up in doing robotics.  :)
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kassy

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Re: The Holocene Extinction
« Reply #458 on: March 03, 2020, 02:45:59 PM »
Study indicates alarming fall in dolphin numbers

A study of how many dolphins are caught in tuna fishing nets estimates the mammals may now be at just 13 per cent of their numbers prior to 1980.

James Cook University’s Dr Putu Mustika was part of an international group that looked at the bycatch from tuna gillnets (including driftnets) in the Indian Ocean. The group was led by Dr Charles Anderson of the Manta Marine organisation in the Maldives.

“We combined results from 10 bycatch sampling programmes between 1981 and 2016 in Australia, Sri Lanka, India and Pakistan to estimate bycatch rates for cetaceans (whales, dolphins and porpoises) across all Indian Ocean tuna gillnet fisheries,” said Dr Mustika.

She said while some of the official data may be unreliable, scientists had been able to come up with a credible picture of the dolphin catch.

Dr Mustika said tuna fishers operating in theIndian Ocean caught about 4.1 million small cetaceans between 1950 and 2018.

“The vast majority of the cetacean bycatch is dolphins. Estimated cetacean bycatch peaked at almost 100,000 a year during 2004−2006, but has declined to 80,000 animals a year, despite an increase in the tuna gillnet fishing effort,” she said.

Dr Mustika said the numbers may be substantially higher as the figures take little or no account of things such as delayed mortality of cetaceans that escape from the nets or mortality associated with ghost nets.

“But the declining cetacean bycatch rates shown by what we can measure suggest current mortality rates are not sustainable. The estimates we have developed show that average small cetacean abundance may currently be 13 percent of the 1980 levels,” she said.

...

Background:

Tuna gillnets deployed in the Indian Ocean vary in length from 100 m to over 30 km in length, and less than 5 m to more than 20 m in depth.

The current cetacean bycatch rate may be in the order of 175 cetaceans per 1000 tonne of tuna, down from an estimate of 600 in the late 1970s.

If tuna abundance is currently in the order of 44% of pre-commercial exploitation (1980) levels, then average cetacean abundance may now be about 13% of pre-fishery levels (175 / 600 × 0.44).

The countries with the largest current gillnet catches of tuna and likely to have the largest cetacean bycatch are (in order): Iran, Indonesia, India, Sri Lanka, Pakistan, Oman, Yemen, UAE and Tanzania.

Iran and Indonesia have no national monitoring of cetacean bycatch. Dr Mustika said some other countries report numbers that may not be accurate.

https://www.jcu.edu.au/news/releases/2020/february/study-indicates-alarming-fall-in-dolphin-numbers
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kassy

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Re: The Holocene Extinction
« Reply #459 on: March 06, 2020, 03:41:38 PM »
Hooded vultures 'on brink of extinction' in Africa after mass poisoning

Accidental ingestion of strychnine believed to be cause of nearly 1,000 deaths in Guinea-Bissau

Nearly 1,000 hooded vultures have died in a mass poisoning in Guinea-Bissau, pushing the endangered species towards the brink of extinction in Africa, according to conservationists.

Vultures were seen apparently searching for water and “bubbling from their beaks”, and hundreds were found dead on the outskirts of two towns, Bafatá and Gabú, which are 30 miles apart, over the past two weeks.

The poisoning is the biggest mass death of vultures for more than a decade, according to the Vulture Conservation Foundation.

The likeliest cause of death is accidental poisoning after strychnine – which is banned in Europe – was used to control the feral dog population around rubbish dumps where vultures, which scavenge on dead animals, also feed.

...

Vulture populations in India have declined by 99% after the birds ingested a toxic veterinary drug, diclofenac, through cattle carcasses it fed on.

In Africa, mass poisoning events largely linked to wildlife crimes are causing the loss of thousands of vultures each year, with other single incidents killing 600 vultures and 400 vultures in southern and eastern parts of the continent.

https://www.theguardian.com/world/2020/mar/06/hooded-vultures-extinction-africa-mass-poisoning
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kassy

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Re: The Holocene Extinction
« Reply #460 on: March 21, 2020, 04:21:07 PM »
Fallout from Australia’s Huge Wildfires Is Choking Rivers

...

As gruesome as the scene had been on land that January day, Pearce’s main concern then, and in the ensuing weeks, has been for a fish, the Macquarie perch. This species, which grows to about 16 inches in length and can live for 25 years, was once abundant and commercially fished throughout the Murray River basin. Today it’s endangered and only found in a handful of sites across southeast Australia, including in this 3.7-mile section of the Mannus Creek. Even before the bush fires, Pearce had been thinking about moving perch out of the creek and into captivity because of declining water quality caused by drought; the fires made that urgent. He managed to net nine perch in the days following the fires—at least some were still alive, he was glad to find—and arranged to return with some colleagues to net more.

Then, on January 19, thunderstorms dumped large amounts of rain in the Mannus Creek catchment area. It was a relief for many, putting out fires and watering parched cattle paddocks, but the downpours triggered disaster in the creek. When Pearce arrived in Bogandyera Nature Reserve with his fish-netting teams around midday on January 20, they watched in “complete and utter despair” as huge volumes of ashy sediment, like dark, runny mud, came down the stream. “My initial feeling was that everything was going to die,” said Pearce, “I just didn’t know how anything was going to survive in that thick soup.”

...

Luiz Silva and Katie Doyle, freshwater fish scientists at Charles Sturt University, have now documented 14 sites where ash-related fish kills occurred across southeastern Australia in recent months.

“We have never seen that extent of fire-related fish kills anywhere in the world,” said Silva, adding that he and Doyle documented fish mortality along more than 40 miles of the upper Murray River, even in its large main channel, where pollution would normally be diluted.

...

At Mannus Creek, one of the primary impacts of the large pulse of ash was a rapid decline in dissolved oxygen levels in the water. With an electronic probe, Pearce documented oxygen levels dropping from an already-low 7.5 milligrams per liter to 0.06 milligrams per liter on January 20—virtually zero. “Everything was trying to get out of the creek,” he recalled. “Freshwater shrimp, yabbies [Australian freshwater crayfish], mayfly larvae, freshwater snails—they were all crawling out.”

Pearce even saw dragonfly larvae emerge from the muck and try to molt into their flying, adult forms. They were too immature, and died while he watched. “I found dead tadpoles and Gambusia [small, non-native mosquitofish], which was surprising, because nothing kills Gambusia normally,” he said. “I even saw platypus swimming about at the surface, all stressed, in the middle of the day. You never see them in the middle of the day.”

Elsewhere in New South Wales, Silva and Doyle found large, dead fish that appeared to have asphyxiated, their gills blackened and clogged with ash. Some had red eyes and appeared to have been “cooked” in fire-heated water. Pulses of ash can cause rapid changes in pH, for example making usually acidic rivers extremely alkaline within a short time, with lethal impacts on river life, said Doyle. Other experts are estimating that hundreds of thousands of fish, at a minimum, have died in southeastern Australia during this fire season.

...

When I visited Mannus Creek this week with Pearce, the creek’s water was beginning to clear up, though it was still very dirty. Although he has seen a few Macquarie perch in recent days, the deep pools that provide cool water for them to find refuge during hot spells were filled with ash and sediment, as were the gravel beds they need to lay their eggs. No breeding habitat for the species was visible. Pearce said that over time, successive floods would normally flush out the sediment. But with the fire burning so hot in the creek catchment, there was little vegetation regrowth to hold the topsoil. The next rains might dump more sediment in the stream rather than cleaning it.

As for the plans to breed threatened fish in captivity, this is easier said than done. Pearce told me that female Macquarie perch are difficult to bring into breeding condition in captive facilities. Lintermans pointed out that the stocky galaxias’ breeding biology is virtually unknown. Fisheries managers will have to try to breed it through trial and error, and they might fail.

https://www.wired.com/story/fallout-from-australias-huge-wildfires-is-choking-rivers/
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kassy

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Re: The Holocene Extinction
« Reply #461 on: April 03, 2020, 01:04:50 AM »
While we fixate on coronavirus, Earth is hurtling towards a catastrophe worse than the dinosaur extinction

...

For example, about 66 million years ago an asteroid hit Earth. The subsequent smashed rocks and widespread fires released massive amounts of carbon dioxide over about 10,000 years. Global temperatures soared, sea levels rose and oceans became acidic. About 80% of species, including the dinosaurs, were wiped out.

And about 55 million years ago, global temperatures spiked again, over 100,000 years or so. The cause of this event, known as the Paleocene-Eocene Thermal Maximum, is not entirely clear. One theory, known as the “methane burp” hypothesis, posits that a massive volcanic eruption triggered the sudden release of methane from ocean sediments, making oceans more acidic and killing off many species.

...

Comparing greenhouse gas levels
Before industrial times began at the end of the 18th century, carbon dioxide in the atmosphere sat at around 300 parts per million. This means that for every one million molecules of gas in the atmosphere, 300 were carbon dioxide.

In February this year, atmospheric carbon dioxide reached 414.1 parts per million. Total greenhouse gas level – carbon dioxide, methane and nitrous oxide combined – reached almost 500 parts per million of carbon dioxide-equivalent

Carbon dioxide is now pouring into the atmosphere at a rate of two to three parts per million each year.

Using carbon records stored in fossils and organic matter, I have determined that current carbon emissions constitute an extreme event in the recorded history of Earth.

My research has demonstrated that annual carbon dioxide emissions are now faster than after both the asteroid impact that eradicated the dinosaurs (about 0.18 parts per million CO2 per year), and the thermal maximum 55 million years ago (about 0.11 parts per million CO2 per year).

https://theconversation.com/while-we-fixate-on-coronavirus-earth-is-hurtling-towards-a-catastrophe-worse-than-the-dinosaur-extinction-130869

One thing that surprised me is that asteroid impact actually beat the PETM then again that is function of time (like those hugest lasers actually shooting in real short time frames).

Off course we know that were the asteroid hit caused problem because of the rock type.

Lots of links in the article.

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Stephen

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The ice was here, the ice was there,   
The ice was all around:
It crack'd and growl'd, and roar'd and howl'd,   
Like noises in a swound!
  Rime of the Ancient Mariner by Samuel Taylor Coleridge

kassy

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Re: The Holocene Extinction
« Reply #463 on: April 11, 2020, 03:37:42 PM »
Stephen i merged your thread into this because where all the past events are.
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Stephen

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Re: The Holocene Extinction
« Reply #464 on: April 12, 2020, 03:31:13 AM »
Stephen i merged your thread into this because where all the past events are.

Doesn't really matter, people are ignoring everything except the pandemic, in both main stream media and on this site.
The ice was here, the ice was there,   
The ice was all around:
It crack'd and growl'd, and roar'd and howl'd,   
Like noises in a swound!
  Rime of the Ancient Mariner by Samuel Taylor Coleridge

nanning

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Re: The Holocene Extinction
« Reply #465 on: April 12, 2020, 08:43:35 AM »
^^
That sort-of matches my observations Stephen.
Sorry for off-topic post. What to do in such situations? React in a different thread? For a quick reply? Aaarrrgghhhh
"It is preoccupation with possessions, more than anything else, that prevents us from living freely and nobly" - Bertrand Russell
"It is preoccupation with what other people from your groups think of you, that prevents you from living freely and nobly" - Nanning
Why do you keep accumulating stuff?

kassy

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Re: The Holocene Extinction
« Reply #466 on: April 12, 2020, 10:49:28 AM »
I agree with both of you.

One trick is to add a relevant article to combine with the comment.

If Emissions Don't Change Drastically, We Could See Abrupt Biodiversity Losses By 2030

A study from the University College of London, England, has detailed how the current rise in global climate puts the Earth’s ecosystems at risk of sudden and catastrophic losses. The findings, published in the journal Nature, outline how worldwide biodiversity could be reduced as a result of ecological disruption caused by changing temperatures and weather systems, and indicates that some of these disruptions may already be underway.

"It's not a slippery slope, but a series of cliff edges, hitting different areas at different times,” said the study's lead author Dr Alex Pigot, from the UCL Centre for Biodiversity & Environment Research, in a statement. "We found that climate change risks to biodiversity don't increase gradually. Instead, as the climate warms, within a certain area most species will be able to cope for a while, before crossing a temperature threshold, when a large proportion of the species will suddenly face conditions they've never experienced before."

To arrive at their conclusions, Dr Pigot and his team used climate model data from as far back as 1850 all the way to 2005 to examine the historic threats to biodiversity in the USA and South Africa. They then cross-referenced this information with the habitat ranges of 30,652 species of birds, mammals, reptiles, amphibians and fish using 100 x 100 kilometer (62 x 62 miles) square grid cells to determine which grids were likely to see an increase in sustained temperatures for more than five years.

...

The researchers posit that under a high-emissions scenario, a global temperature increase of 4°C by 2100 could see one in in five constituent species in 15 percent of the world’s ecosystems cross this threshold for livable conditions. They predict that these changes could be sufficient to cause irreversible damage to the functioning of the ecosystem. If emissions are reduced and temperatures increase by 2°C or less, this threshold event for one in five keystone species could be seen in just 2 percent or fewer ecosystems across the globe.

While a considerable improvement on 15 percent, the researchers warn that the 2 percent includes our most biodiverse ecosystems, such as coral reefs. They predict this impact will begin to be felt by 2030 for the Earth’s tropical oceans. Their models also indicate that the same effects on biodiversity will be seen in some of the Earth’s largest forest ecosystems by 2050.

https://www.iflscience.com/environment/if-emissions-dont-change-drastically-we-could-see-abrupt-biodiversity-losses-by-2030/

The projected timing of abrupt ecological disruption from climate change article is available via the news article.
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oren

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Re: The Holocene Extinction
« Reply #467 on: April 12, 2020, 04:30:47 PM »
I should point out this may be a misconception. Many people are reading these threads, but not many have something to contribute. Ecosystem destruction (and other anthropogenic effects) is a slow moving train wreck, with the writing on the wall now for a long time. COVID-19 is a fast moving pandemic so lots of updates and lots of unknowns, and I should add a lower knowledge level required for posting... why I post easily there.
Don't count the number of posts, it's misleading. And remember the large number of lurkers who read this site daily.

kassy

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Re: The Holocene Extinction
« Reply #468 on: April 17, 2020, 07:52:07 PM »
A losing battle to protect forest elephants in Central Africa

...

Forest elephants roam these areas and the increasing fragmentation of their habitats and isolation from other populations make them extremely vulnerable.

The elephant population of the Dja conservation complex face an uncertain future.

The 97,800 ha of unprotected forest around the reserve, for example, is the theatre of multiple land uses and natural resource use practices. These not only threaten to isolate the reserve genetically, but also constitute the launching pad for most illegal incursions inside it.

Among the greatest threats to the survival of forest elephants in the area is commercial logging. Although no logging concession is granted inside the reserve, the entire surrounding forests are attributed as logging concessions by the central administration in Yaoundé.

With commercial logging come two major threats to the survival of the elephants and the ecological integrity of the Dja Reserve.

The first is the establishment of permanent or semi-permanent human settlements or logging camps, usually in pristine forest areas, which attract thousands of migrant workers and their relatives, most of whom are associated with hunting for and trade in ivory for quick financial gains.

The second threat is commercial hunting, usually by the logging camp residents and outside hunters. Due to the heavy machinery and equipment involved, commercial logging provides not only access to previously unexplored and remote, intact forests, but is also the means to take ivory to distant markets.

The Cameroon railway, that passes through the peripheral areas of the Deng-Deng National Park and Dja Biosphere Reserve corridor, has led to serious problems of noise. It has also facilitated access to remote areas and thus increased transportation of elephant bush meat and ivory.

The presence of government, economic operators and external development bodies such as Cameroon Oil Transportation Co and Electricity Development Cooperation in the area has led to an influx of people into the buffer zone.

The increased human population has also led to a high demand for elephant products in the area, thereby promoting illegal hunting and trafficking of ivory.

Earlier, hunters mainly employed traditional trapping techniques. But with the increasing demand for ivory and bush meat, modern techniques are now being used such as automated guns and rifles for hunting.

https://www.downtoearth.org.in/blog/africa/a-losing-battle-to-protect-forest-elephants-in-central-africa-70511

Elephants are smart. They also have a map of their world and they must see it shrinking.
I can picture a matriarch pondering where to go now when another area gets cut of or seems to dangerous.

I only ever saw the asian elephants up close but they were magnificent when bathing.
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kassy

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Re: The Holocene Extinction
« Reply #469 on: May 01, 2020, 01:26:44 PM »
Genetics Reveals Warming Seas May Drive Narwhals Into Extinction

...

There are approximately 200,000 narwhals alive today. They are migratory and form three separate populations that are named for where they summer. Most of them either summer in Baffin Bay or Hudson’s Bay whilst a third, much smaller population that numbers around 10,000 individuals, lives along the eastern coast of Greenland and around the Norwegian island of Svalbard.

Narwhals show an absence of a strong geographic pattern
A team of researchers from Denmark, Germany, Norway, the U.K. and Canada collected tissue samples from animals killed by Inuit hunters in Canada and Greenland, and also collected samples from narwhal remains found in archeological digs in northern Europe and Russia. They even obtained special permission to drill tiny samples from the two Norwegian narwhal tusks that adorn Denmark’s special anointing throne chair, constructed in 1660.

DNA mitogenomes, which are inherited only from an individual’s mother, were obtained from these tissue samples. They confirmed there are three populations of narwhals; the two largest populations live off the northeastern coasts of Canada and a third lives along the eastern coast of Greenland (Figure 1a).

The DNA mitogenomes also revealed these three narwhal populations are very closely related to each other (Figure 1b), which is surprising because each population shows fidelity to their migratory routes or to their summering areas. Even more surprising is that narwhals showed the lowest genetic diversity ever discovered in any marine mammal (Figure 2).

...

The researchers used a combination of genetics and habitat modelling to investigate how previous climate shifts impacted the distribution of narwhals, and to estimate how climate change could affect the future of this species. These models estimated that narwhals will experience a 25% decline in suitable habitat by the end of this century, and this habitat will shift northward by 1.6 degrees.

In addition to this northward shift, the study also predicts that suitable narwhal habitat will shrink as sea temperatures continue to rise and sea ice continues to melt. These findings suggest that narwhals will have to move northward if they are to access the special habitat — and especially the specialized diet (ref) — they need to thrive. But even if they do move northward, this will not protect them. Narwhals will be crowded into ever smaller habitats and will become increasingly vulnerable to intensifying human encroachment, changes in prey availability, new diseases and competitors, and more frequent predation by orcas.

Narwhals depend heavily upon cold deep marine waters

This study of narwhal DNA also allowed the researchers to generate habitat models showing where they lived in the past, and where they live now. In the past, narwhals had a larger range, which suggested they had a larger population, too. But their range contracted after the last Ice Age — a common scenario amongst all Arctic mammals.

The study uncovered evidence that the survival of narwhals is heavily dependent on habitat availability — they require deep, cold water filled with squid, shrimp and a variety of fish to prey upon. This raises concerns about the future of narwhals because they are unique amongst marine mammals: they live exclusively in the Atlantic Ocean, whereas other marine mammals are found throughout the entire Arctic, so it’s an open question as to what may happen to them as sea ice continues to melt. This melting scenario is assured: a recent study predicts that summer sea ice will completely disappear from the Arctic before 2050 (ref) — and this, of course, will have devastating consequences for all Arctic species and ecosystems.

https://www.forbes.com/sites/grrlscientist/2020/04/30/genetics-reveals-warming-seas-may-drive-narwhals-into-extinction/#54170b476e41

Influence of past climate change on phylogeography and demographic history of narwhals, Monodon monoceros

https://doi.org/10.1098/rspb.2019.2964
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kassy

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Re: The Holocene Extinction
« Reply #470 on: May 05, 2020, 11:44:40 AM »
Crabeater seals in Antartica will have to swim farther distances to find food sources as warming oceans reduce the amount of krill in the waters

...

A new study from the Institute of Marine Sciences at UC Santa Cruz modeled the seasonal movements and feeding patterns of crabeater seals and krill, their primary food source.

The data was collected from electronic tags placed on crabeater seals on the Antarctic peninsula dating as far back as 2001, and combined with environmental models showing the effects of climate change on the region, and ocean circulation models. 

..

Past research has shown that krill in Antarctica have already move 270 miles southward over the last 90 years.

'The shift in krill habitat away from coastal waters in the north has big implications for species like penguins and fur seals, which can't make long foraging trips because they have to come back to land to feed their offspring,' Huckstadt said. 'It will be challenging for a lot of species.'

'Things are changing so fast in Antarctica, the changes we're seeing in our model might be coming sooner than we expected.'

The growing presence of commercial krill fishing boats has  also placed environmental pressure on crabeater seals, as they compete for a dwindling supply of food with a growing number of human and non-human predators.

'We don't really have a good grasp on how fishing pressure will change in the future, and that's one reason so many marine protected areas have been proposed for the western Antarctic Peninsula,' Huckstadt said.

Recent estimates suggest commercial krill fishing removes at least 300,000 tons of krill from the Antarctic each year.

...

https://www.dailymail.co.uk/sciencetech/article-8286437/Climate-change-slowly-killing-main-source-food-crabeater-seals.html
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kassy

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Re: The Holocene Extinction
« Reply #471 on: May 26, 2020, 07:23:11 PM »
'Billions of years of evolutionary history' under threat

Scientists say more than 50 billion years of cumulative evolutionary history could be lost as humans push wildlife to the brink.

"Weird and wonderful" animals unlike anything else on Earth are sliding silently toward extinction, they say.

And regions home to the greatest amounts of unique biodiversity are facing unprecedented human pressures.

They include the Caribbean, Western Ghats of India and large parts of Southeast Asia.

The study, published in Nature Communications, highlights priority species for conservation, based on their evolutionary distinctiveness.

"These species are weird and wonderful and there is nothing like them on Earth," said Rikki Gumbs of ZSL's EDGE of Existence programme and Imperial College London.

He said the analysis reveals "the incomprehensible scale of the losses we face if we don't work harder to save global biodiversity".

https://www.bbc.com/news/science-environment-52808103

In all places we keep taking from nature decreasing the ranges of what lives there.

We should invest in keeping those last reserves growing or reconnect them.
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vox_mundi

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Re: The Holocene Extinction
« Reply #472 on: May 26, 2020, 07:32:34 PM »
The earth is 4.5 Billion years old

The universe is ~ 13.5 Billion years old

50 Billion years predates the universe by 36.5 billion years.
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Re: The Holocene Extinction
« Reply #473 on: May 26, 2020, 07:40:03 PM »
From the linked article:

They found a combined 50 billion years of evolutionary heritage, at least, were under threat from human impacts such as urban development, deforestation and road building.

Rikki Gumbs said the numbers are very large because species are evolving in parallel; for reptiles alone you get a figure of 13 billion years (about the age of the Universe).

He said: "The tree of life is so vast and extinction is so widely spread across the tree of life that when you begin to add up all these numbers you end up with these kinds of incomprehensible figures of more than 50 billion years."

kassy

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Re: The Holocene Extinction
« Reply #474 on: May 26, 2020, 07:47:17 PM »
Yes it´s the fork of life. The other side is losing (innocent) things you can never get back.
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Re: The Holocene Extinction
« Reply #475 on: May 28, 2020, 03:32:48 AM »
Study Shows Erosion of Ozone Layer Responsible for Mass Extinction Event
https://phys.org/news/2020-05-erosion-ozone-layer-responsible-mass.html



Researchers at the University of Southampton have shown that an extinction event 360 million years ago, that killed much of the Earth's plant and freshwater aquatic life, was caused by a brief breakdown of the ozone layer that shields the Earth from damaging ultraviolet (UV) radiation. This is a newly discovered extinction mechanism with profound implications for our warming world today.

There have been a number of mass extinction in the geological past. Only one was caused by an asteroid hitting the Earth, which was 66 million years ago when the dinosaurs became extinct. Three of the others, including the end Permian Great Dying, 252 million years ago, were caused by huge continental scale volcanic eruptions that destabilised the Earth's atmospheres and oceans.

Now, scientists have found evidence showing it was high levels of UV radiation which collapsed forest ecosystems and killed off many species of fish and tetrapods (our four limbed ancestors) at the end of the Devonian geological period, 359 million years ago. This damaging burst of UV radiation occurred as part of one of the Earth's climate cycles, rather than being caused by a huge volcanic eruption.

The ozone collapse occurred as the climate rapidly warmed following an intense ice age and the researchers suggest that the Earth today could reach comparable temperatures, possibly triggering a similar event. Their findings are published in the journal Science Advances.

... The scientists concluded that, during a time of rapid global warming, the ozone layer collapsed for a short period, exposing life on Earth to harmful levels of UV radiation and triggering a mass extinction event on land and in shallow water at the Devonian-Carboniferous boundary.

Following melting of the ice sheets, the climate was very warm, with the increased heat above continents pushing more naturally generated ozone destroying chemicals into the upper atmosphere. This let in high levels of UV-B radiation for several thousand years.

During the extinction, plants selectively survived, but were enormously disrupted as the forest ecosystem collapsed. The dominant group of armoured fish became extinct. Those that survived—sharks and bony fish—remain to this day the dominant fish in our ecosystems.

... Professor Marshall says his team's findings have startling implications for life on Earth today: "Current estimates suggest we will reach similar global temperatures to those of 360 million years ago, with the possibility that a similar collapse of the ozone layer could occur again, exposing surface and shallow sea life to deadly radiation. This would move us from the current state of climate change, to a climate emergency."

J.E.A. Marshall el al., "UV-B radiation was the Devonian-Carboniferous boundary terrestrial extinction kill mechanism," Science Advances (2020).
http://dx.doi.org/10.1126/sciadv.aba0768
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vox_mundi

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Re: The Holocene Extinction
« Reply #476 on: June 01, 2020, 09:55:22 PM »
Loss of Land-Based Vertebrates Is Accelerating, Study Finds
https://phys.org/news/2020-06-loss-land-based-vertebrates.html

In 2015, Stanford biologist Paul Ehrlich coauthored a study declaring the world's sixth mass extinction was underway. Five years later, Ehrlich and colleagues at other institutions have a grim update: the extinction rate is likely much higher than previously thought and is eroding nature's ability to provide vital services to people.

Their new paper, published this week in Proceedings of the National Academy of Sciences, indicates the wildlife trade and other human impacts have wiped out hundreds of species and pushed many more to the brink of extinction at an unprecedented rate.

For perspective, scientists estimate that in the entire twentieth century, at least 543 land vertebrate species went extinct. Ehrlich and his coauthors estimate that nearly the same number of species are likely to go extinct in the next two decades alone.



... To better understand the extinction crisis, the researchers looked at the abundance and distribution of critically endangered species. They found that 515 species of terrestrial vertebrates— 1.7 percent of all the species they analyzed— are on the brink of extinction, meaning they have fewer than 1,000 individuals remaining. About half of the species studied have fewer than 250 individuals left. Most of the highly endangered species are concentrated in tropical and subtropical regions that are affected by human encroachment, according to the study.

In addition to rising extinction rates, the cumulative loss of populations—individual, localized groups of a particular species- and geographic range has led to the extinction of more than 237,000 populations of those 515 species since 1900, according the researchers' estimates. With fewer populations, species are unable to serve their function in an ecosystem, which can have rippling effects. For example, when overhunting of sea otters—the main predator of kelp-eating sea urchins—led to kelp die-offs in the 1700s, the kelp-eating sea cow went extinct.

... The loss of endangered creatures could have a domino effect on other species, according to the researchers. The vast majority—84 percent—of species with populations under 5,000 live in the same areas as species with populations under 1,000. This creates the conditions for a chain reaction in which the extinction of one species destabilizes the ecosystem, putting other species at higher risk of extinction.

"Extinction breeds extinction," the study authors write. Because of this threat, they call for all species with populations under 5,000 to be listed as critically endangered on the International Union for Conservation of Nature Red List, an international database used to inform conservation action on a global scale.

Gerardo Ceballos el al., "Vertebrates on the brink as indicators of biological annihilation and the sixth mass extinction," PNAS (2020).
https://www.pnas.org/cgi/doi/10.1073/pnas.1922686117
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Re: The Holocene Extinction
« Reply #477 on: June 09, 2020, 10:16:51 AM »
Well, in this topic perhaps it's good to share some philosophical mumblings too, by looking at historical context. Basically as it is claimed it is the 6th mass extinction event on planet Earth in the last 450 Million years.

But really looking at things at a cosmic scale, humans are just a dot in the universe, both in space and time.

I find it intriguing how humans have largely developed such an egocentric worldview that they consider themselves massively important, "above nature" and that the world revolves around them. While on a cosmic or even planetary level our species just come and go, and are really nothing in terms of planetary timescales, let alone cosmic ones.

Fun to look at this perspective. And really on planetary timescales this mass extinction isn't really anything extraordinary either, because as mentioned these things have happened before. It's just tragic for humans, because this time we are involved in this as well.

vox_mundi

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Re: The Holocene Extinction
« Reply #478 on: June 09, 2020, 10:25:29 AM »
Scientists Lament 'Humpty Dumpty' Effect On World's Spectacular, Rare Wildlife
https://phys.org/news/2020-06-scientists-lament-humpty-dumpty-effect.html

Some of the world's largest, most spectacular and unheralded mammals are silently slipping away, species like Tibetan wild yaks and Patagonia's huemul, Bhutan's takin and Vietnam's saola. Even Africa's three species of zebras and wildebeest have suffered massive reductions over the last several decades.

The research team said worldwide food webs have become irretrievably altered by humans, with little hope to reconstitute even recent past conditions or to put back the ecological functions once created by native species.

The reasons for these losses are more than disease and habitat fragmentation, deforestation or wildlife trade, according to researchers. Ultimately, the cause is rampant human population growth. And unless human behavior changes in unprecedented ways, these scientists warn that future communities of these mammals will never resemble those of the recent past or even today.

The findings are based on a new study, "Disassembled food webs and messy projections: modern ungulate communities in the face of unabating human population growth," published June 9 in Frontiers in Ecology and Evolution.

"We all must realize we're members of a broad, beautiful and living planet, and we must find ways to subsist in this together or suffer more severe consequences than what we already see," said Berger, also a senior scientist at the Wildlife Conservation Society (WCS). "For many assemblages of animals, we are nearing a moment in time, when, like Humpty Dumpty, we will not be able to put things back together again."

Joel Berger et al, Disassembled Food Webs and Messy Projections: Modern Ungulate Communities in the Face of Unabating Human Population Growth, Frontiers in Ecology and Evolution (2020).
https://www.frontiersin.org/articles/10.3389/fevo.2020.00128/full
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Re: The Holocene Extinction
« Reply #479 on: July 02, 2020, 10:27:46 PM »
Major New Paleoclimatology Study Shows Global Warming Has Upended 6,500 Years of Cooling
https://phys.org/news/2020-06-major-paleoclimatology-global-upended-years.html



Over the past 150 years, global warming has more than undone the global cooling that occurred over the past six millennia, according to a major study published June 30 in Nature Research's Scientific Data, "Holocene global mean surface temperature, a multi-method reconstruction approach."

The findings show that the millennial-scale global cooling began approximately 6,500 years ago when the long-term average global temperature topped out at around 0.7°C warmer than the mid-19th century. Since then, accelerating greenhouse gas emissions have contributed to global average temperatures that are now surpassing 1°C above the mid-19th century.

The research team worked in collaboration with scientists from research institutions all over the world to reconstruct the global average temperature over the Holocene Epoch—the period following the Ice Age and beginning about 12,000 years ago.

"Previous work has shown convincingly that the world naturally and slowly cooled for at least 1,000 years prior to the middle of the 19th century, when the global average temperature reversed course along with the build-up of greenhouse gases. This study, based on a major new compilation of previously published paleoclimate data, combined with new statistical analyses, shows more confidently than ever that the millennial-scale global cooling began approximately 6,500 years ago."

... Since the mid-19th century, global warming has climbed to about 1°C, suggesting that the global average temperature of the last decade (2010-2019) was warmer than anytime during the present post-glacial period.

Holocene global mean surface temperature, a multi-method reconstruction approach, Scientific Data, 2020
https://www.nature.com/articles/s41597-020-0530-7
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Re: The Holocene Extinction
« Reply #480 on: July 03, 2020, 03:10:43 PM »
Farewell smooth handfish: What can we learn from the world's first marine fish extinction?

Earlier this month, a group of Australian scientists confirmed a depressing landmark for our blue planet: The first marine fish of modern times has been declared extinct on the IUCN RedList. The smooth handfish (Sympterichthys unipennis) was one of 14 (now 13) species of handfish, beautifully patterned creatures with a distinctly "missing link" look about them. Residing only in south-eastern Australian waters, these striking animals are bottom-dwellers that use their highly modified pectoral fins to "walk" along the seabed.

Smooth handfish were once so common in south-eastern Australia that it was one of the first species collected in an early scientific exploration of the country in the early 1800s by French zoologist François Péron. The species is now only known from the specimen collected in that expedition; during extensive in-water surveys of the species' limited range since 2000, divers found no smooth handfish individuals, declaring it extinct.

...

Given the way many marine fish breed (through sending their larvae into the water column, where they may disperse across great distances) and how variably human pressures can affect them, confirming that a marine fish species is extinct is notoriously difficult. Handfish are unusual fish in that they don't have a midwater stage for their larvae. Instead, they give birth to fully formed juveniles directly on to the seabed. This means they only live in a handful of highly specialised areas and are therefore highly vulnerable to being fished or having the habitat they breed on disturbed. The story of the smooth handfish should stop us in our tracks and make us think long and hard about what price we're willing to pay for our seafood, about what lies behind the notion of "sustainable" fisheries.

Destructive fishing practices

The fishing activities that probably contributed to the extinction of the smooth handfish ended 53 years ago. The scientists note in their Redlist assessment that "this species was probably impacted, through both direct mortality as bycatch and destruction of habitat, by the large historical scallop fishery that was active in the region through the 20th century until the fishery collapsed in 1967". So, we didn't hunt or overfish the handfish to extinction—it wasn't being targeted. We overfished the scallops and the handfish was caught in the crossfire. Like the blind cave fish threatened by cement extraction or the scaly-foot snail pushed to the brink by proposed deep seabed mining, the handfish was the collateral damage of the destructive methods used to extract resources from our planet.

and more on:
https://phys.org/news/2020-07-farewell-smooth-handfish-world-marine.html
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vox_mundi

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Re: The Holocene Extinction
« Reply #481 on: July 16, 2020, 02:47:34 PM »
North Atlantic Right Whales Now Officially 'One Step From Extinction
https://www.theguardian.com/environment/2020/jul/16/north-atlantic-right-whales-critically-endangered-one-step-from-extinction

With their population still struggling to recover from over three centuries of whaling, the North Atlantic right whale is now just “one step from extinction”, according to the International Union for the Conservation of Nature (IUCN). The IUCN last week moved the whale’s status on their Red List from “endangered” to “critically endangered” – the last stop before the species is considered extinct in the wild.

The status change reflects the fact that fewer than 250 mature individuals probably remain in a population of roughly 400. While grim, scientists and conservationists expressed hope that this move may help speed up protections for these dwindling giants.

... Often found leisurely filtering plankton at the ocean surface, the right whale species was once highly targeted by whalers: their slow speed made them easy to hunt, and they float when killed, thanks to thick blubber.

That slow surface feeding today leads to these whales being struck by boat propellers or becoming fatally snarled in fishing gear. According to the IUCN, of the 30 deaths or serious injuries to North Atlantic right whales recorded between 2012 and 2016, 26 were caused by fishing gear entanglement.
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Re: The Holocene Extinction
« Reply #482 on: July 20, 2020, 10:15:01 PM »
Climate Change On Track to Wipe Out Polar Bears by 2100
https://phys.org/news/2020-07-climate-track-polar.html

Climate change is starving polar bears into extinction, according to research published Monday that predicts the apex carnivores could all but disappear within the span of a human lifetime.

In some regions they are already caught in a vicious downward spiral, with shrinking sea ice cutting short the time bears have for hunting seals, scientists reported in Nature Climate Change.

Their dwindling body weight undermines their chances of surviving Arctic winters without food, the scientists added.

"The bears face an ever longer fasting period before the ice refreezes and they can head back out to feed," Steven Amstrup, who conceived the study and is chief scientist of Polar Bears International, told AFP.

A male bear, for example, in the West Hudson Bay population that is 20 percent below its normal body weight when fasting begins will only have enough stored energy to survive about 125 days rather than 200 days.

On current trends, the study concluded, polar bears in 12 of 13 subpopulations analysed will have been decimated within 80 years by the galloping pace of change in the Arctic, which is warming twice as fast as the planet as a whole.

There is not enough data for six others to make a determination as to their fate.

"By 2100, recruitment"—new births—"will be severely compromised or impossible everywhere except perhaps in the Queen Elizabeth Island subpopulation," in Canada's Arctic Archipelago, said Amstrup.

There are approximately 25,000 Urus maritimus left in the wild today.


Maps of polar bear populations showing the progression towards extinction by the end of the century

Fasting season length sets temporal limits for global polar bear persistence, Nature Climate Change (2020).
https://www.nature.com/articles/s41558-020-0818-9
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gerontocrat

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Re: The Holocene Extinction
« Reply #483 on: July 28, 2020, 09:17:46 PM »
The data on what has ALREADY HAPPENED is stark.

https://www.theguardian.com/environment/2020/jul/27/migratory-river-fish-populations-plunge-76-in-past-50-years
Migratory river fish populations plunge 76% in past 50 years
Quote
Populations of migratory river fish around the world have plunged by a “catastrophic” 76% since 1970, an analysis has found.

The fall was even greater in Europe at 93%, and for some groups of fish, with sturgeon and eel populations both down by more than 90%.

Species such as salmon, trout and giant catfish are vital not just to the rivers and lakes in which they breed or feed but to entire ecosystems. By swimming upstream, they transport nutrients from the oceans and provide food for many land animals, including bears, wolves and birds of prey.

The migratory fish are also critical for the food security and livelihoods of millions of people around the world, while recreational fishing is worth billions of dollars a year. The causes of the decline are the hundreds of thousands of dams around the world, overfishing, the climate crisis and water pollution.

The scientists said the situation may be even bleaker than it seemed, as many declines began before 1970. Populations of sturgeon in the Great Lakes of North America, for example, have dropped by 95% from historic levels. Furthermore, suitable data has not been gathered on species in some of the world’s most biodiverse rivers such as the Mekong, Congo, Amazon and Yangtze, where researchers fear there will be hundreds of fish extinctions in the coming decades.

The average fall in populations was 84% in Latin America, while there has been a 59% decrease in Asia-Oceania, although there is limited data there and not enough from Africa to determine any reliable trend. In North America, the fall was less dramatic, at 28%. This is probably because large declines occurred before 1970, but also as a result of a growing number of dams being removed.

“For migratory fish, there’s nothing worse than a dam,” said Zeb Hogan, at the University of Nevada and an author of the new report. He said the good news was that fish could return quickly: “Almost without exception, where dams have been removed, you see populations bounce back, often much more quickly than anyone anticipated.”

Source of article : https://www.worldfishmigrationfoundation.com/living-planet-index-2020
https://worldfishmigrationfoundation.com/wp-content/uploads/2020/07/LPI_report_2020.pdf
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glennbuck

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Re: The Holocene Extinction
« Reply #484 on: July 28, 2020, 09:38:12 PM »
The data on what has ALREADY HAPPENED is stark.


Migratory river fish populations plunge 76% in past 50 years

Awful looks like it will not be long before we are on the Menu!

Nearly 3 billion animals were killed or displaced by Australia’s devastating bushfire season of 2019 and 2020, according to scientists who have revealed for the first time the scale of the impact on the country’s native wildlife.

The Guardian has learned that an estimated 143 million mammals, 180 million birds, 51 million frogs and a staggering 2.5 billion reptiles were affected by the fires that burned across the continent.

https://www.theguardian.com/environment/2020/jul/28/almost-3-billion-animals-affected-by-australian-megafires-report-shows-aoe

kassy

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Re: The Holocene Extinction
« Reply #485 on: July 29, 2020, 09:33:39 AM »
Only 1950s Kids Will Recognize This Endangered Fish

New research conducted in Tanzania is providing a chilling example of shifting baselines: the idea that how much an ecosystem appears to have changed depends on when one starts paying attention. Through a series of interviews with Tanzanian fishers, people who spend nearly every day out on the water, scientists found a troubling trend: while all of the older fishers could recognize sawfish, only a handful of young fishers had even heard of these amazing and endangered fish. The research, led by Gill Braulik, a marine ecologist at the University of St Andrews in Scotland, in collaboration with Tanzanian scientists, suggests that sawfish have nearly completely disappeared from Tanzanian waters in just a few decades.

Sawfish are among the most endangered marine fishes in the world. The sawblade-like rostrum of these shark-like rays gets easily tangled in fishing gear, and by-catch has become an existential threat for the five sawfish species that were once common across a large chunk of the world. Habitat destruction, too, is a major impediment to sawfish survival—all five species are now considered endangered or critically endangered by the International Union for Conservation of Nature. But as with any environmental issue, getting people to change their behavior to help solve a problem is difficult if they don’t even know a problem exists. And if people grow up in a world without a species in it, they may not realize what they’re missing.

“We don’t even really know what to restore because [almost] nobody is alive who remembers what has been lost,” says Braulik. “The environment is changing so fast that humans are losing the knowledge of what it used to be like. These results are a reminder of how incredibly abundant and diverse the Tanzanian oceans must have been, but now they are so depleted. None of us can envision what the world was like before it became so changed by humans.”

and much more:
https://www.hakaimagazine.com/news/only-1950s-kids-will-recognize-this-endangered-fish/

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The Walrus

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Re: The Holocene Extinction
« Reply #486 on: July 29, 2020, 04:06:29 PM »
Climate Change On Track to Wipe Out Polar Bears by 2100
https://phys.org/news/2020-07-climate-track-polar.html

Climate change is starving polar bears into extinction, according to research published Monday that predicts the apex carnivores could all but disappear within the span of a human lifetime.

In some regions they are already caught in a vicious downward spiral, with shrinking sea ice cutting short the time bears have for hunting seals, scientists reported in Nature Climate Change.

Their dwindling body weight undermines their chances of surviving Arctic winters without food, the scientists added.

"The bears face an ever longer fasting period before the ice refreezes and they can head back out to feed," Steven Amstrup, who conceived the study and is chief scientist of Polar Bears International, told AFP.

A male bear, for example, in the West Hudson Bay population that is 20 percent below its normal body weight when fasting begins will only have enough stored energy to survive about 125 days rather than 200 days.

On current trends, the study concluded, polar bears in 12 of 13 subpopulations analysed will have been decimated within 80 years by the galloping pace of change in the Arctic, which is warming twice as fast as the planet as a whole.

There is not enough data for six others to make a determination as to their fate.

"By 2100, recruitment"—new births—"will be severely compromised or impossible everywhere except perhaps in the Queen Elizabeth Island subpopulation," in Canada's Arctic Archipelago, said Amstrup.

There are approximately 25,000 Urus maritimus left in the wild today.


This is just a repeat of inaccurate information.  As winter temperatures warm, the polar bear hibernation period decreases.  This decrease can be 30% or more.  The bears simply do not need as much body mass to sustain them through a shorter hibernation period.  The absence of any decrease in polar numbers worldwide should help to diffuse this type of misinformation.  To quote Mark Twain, the death of the polar bear "has been greatly exaggerated."

kassy

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Re: The Holocene Extinction
« Reply #487 on: July 29, 2020, 06:12:11 PM »
Or maybe look up the actual study to see what it is about.

Fasting season length sets temporal limits for global polar bear persistence

Abstract
Polar bears (Ursus maritimus) require sea ice for capturing seals and are expected to decline range-wide as global warming and sea-ice loss continue1,2. Estimating when different subpopulations will likely begin to decline has not been possible to date because data linking ice availability to demographic performance are unavailable for most subpopulations2 and unobtainable a priori for the projected but yet-to-be-observed low ice extremes3. Here, we establish the likely nature, timing and order of future demographic impacts by estimating the threshold numbers of days that polar bears can fast before cub recruitment and/or adult survival are impacted and decline rapidly. Intersecting these fasting impact thresholds with projected numbers of ice-free days, estimated from a large ensemble of an Earth system model4, reveals when demographic impacts will likely occur in different subpopulations across the Arctic. Our model captures demographic trends observed during 1979–2016, showing that recruitment and survival impact thresholds may already have been exceeded in some subpopulations. It also suggests that, with high greenhouse gas emissions, steeply declining reproduction and survival will jeopardize the persistence of all but a few high-Arctic subpopulations by 2100. Moderate emissions mitigation prolongs persistence but is unlikely to prevent some subpopulation extirpations within this century.

https://www.nature.com/articles/s41558-020-0818-9

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The Walrus

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Re: The Holocene Extinction
« Reply #488 on: July 29, 2020, 08:14:16 PM »
The seal issues always seems to rear its ugly head, whenever the polar bear discussion arises.  Yet, polar bears do much worse when there is more sea ice, as there is no place to hunt for seals.  When the polar bears awaken earlier, the sea ice has already begun to break up, making for optimal hunting.  The article makes numerous assumptions that are not support by the data.

vox_mundi

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Re: The Holocene Extinction
« Reply #489 on: July 29, 2020, 08:30:51 PM »
So where's your data?
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

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interstitial

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Re: The Holocene Extinction
« Reply #490 on: July 29, 2020, 08:45:44 PM »
Which assumptions do they make that are not supported by the data?

The Walrus

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Re: The Holocene Extinction
« Reply #491 on: July 29, 2020, 09:00:47 PM »
Which assumptions do they make that are not supported by the data?

"Estimating when different subpopulations will likely begin to decline has not been possible to date because data linking ice availability to demographic performance are unavailable and unobtainable a priori for the projected but yet-to-be-observed low ice extremes."

Yet they go on to make the very same estimates that they claim are not possible.

Sebastian Jones

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Re: The Holocene Extinction
« Reply #492 on: July 30, 2020, 05:33:53 AM »
Dear Walrus,
I'm not sure where you get your Polar bear biology.
Polar bears don't hibernate.
They actually fatten up in winter when they hunt seals through the ice.
They lose weight in summer because they cannot catch seals.
The longer the ice free season, the fewer calories they can get.
This is why there are no polar bears in California, despite there being an abundance of seals and sea lions.

The Walrus

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Re: The Holocene Extinction
« Reply #493 on: July 30, 2020, 04:49:08 PM »
Yes, technically it is not a true hibernation as their body temperature does not decrease.  However, the bears can reduce their metabolic rate, while maintaining body temperature, a state sometimes called "walking hibernation."  Similarly, a female polar bear will enter the same state, often referred to as "denning."  In either case, less nutrition is required to maintain the lower metabolic rate.  As the winter temperature warms, less nutrition is required to maintain body temperature. 

Polar bears do not fatten up in winter, as the solid sea ice prevents hunting.  Rather, they catch seals in spring and early summer. when the ice begins to break up and seals emerge from their dens.  The longer the summer ice-free season, the fewer calories, but this is compensated for by a shorter winter ice-clad season.  Areas which have experienced thick spring ice in the past have had detrimental effects on the survival of polar bear cubs.

Sebastian Jones

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Re: The Holocene Extinction
« Reply #494 on: July 30, 2020, 06:49:46 PM »
I was responding to this bolded sentence from your post
The seal issues always seems to rear its ugly head, whenever the polar bear discussion arises.  Yet, polar bears do much worse when there is more sea ice, as there is no place to hunt for seals.  When the polar bears awaken earlier, the sea ice has already begun to break up, making for optimal hunting.  The article makes numerous assumptions that are not support by the data.
I admit that I'm not a Polar bear biologist, so that I've never heard of "walking hibernation" is perhaps not surprising. Gonna have to do some research! Fortunately I do know some top Polar bear bios.

You indicate that too much ice is tough on bears. Do you know what is the optimal amount of ice, and when? Knowing this we should be able to predict where Polar bears are doing well, and to project where they will thrive into the future.

Sebastian Jones

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Re: The Holocene Extinction
« Reply #495 on: July 30, 2020, 07:07:33 PM »
It appears that Walking Hibernation was a hypothesis found to not exist.
"Using the body core temperature as a measure of metabolic activity (the more the bear was eating, the higher the active metabolism and the higher the temperature), the research team found no sudden temperature changes, which would have otherwise hinted at a bear entering the suggested state of “walking hibernation.” "
"ll evidence points to the fact that polar bears possess no special trick to help them survive lengthy periods without food. Instead, they lose weight just like any other starving mammal. To survive long-term, polar bears need a good platform of sea ice from which to hunt seals. In short: no sea ice = no polar bears."
https://polarbearsinternational.org/news/article-polar-bears/polar-bear-questions-do-polar-bears-undergo-walking-hibernation/

The Walrus

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Re: The Holocene Extinction
« Reply #496 on: July 30, 2020, 07:19:07 PM »
I was responding to this bolded sentence from your post
The seal issues always seems to rear its ugly head, whenever the polar bear discussion arises.  Yet, polar bears do much worse when there is more sea ice, as there is no place to hunt for seals.  When the polar bears awaken earlier, the sea ice has already begun to break up, making for optimal hunting.  The article makes numerous assumptions that are not support by the data.
I admit that I'm not a Polar bear biologist, so that I've never heard of "walking hibernation" is perhaps not surprising. Gonna have to do some research! Fortunately I do know some top Polar bear bios.

You indicate that too much ice is tough on bears. Do you know what is the optimal amount of ice, and when? Knowing this we should be able to predict where Polar bears are doing well, and to project where they will thrive into the future.

I am not sure than anyone truly knows how much ice is optimal.  We do know that no ice or all ice makes seal hunting nearly impossible.  Since the bears are known to travel large distances for food and are not territorial, the theory is that they will simply move to optimal hunting grounds.  Speculation is that Greenland and the Canadian archipelago would be the top choice, as ice remains there year-round, and melting could open up more water holes.  The issue would then become how many bears the area could support.

Sebastian Jones

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Re: The Holocene Extinction
« Reply #497 on: July 30, 2020, 07:39:43 PM »
Agreed Walrus. I just noticed that this discussion morphed into something perhaps better taken place in the Wildlife thread....https://forum.arctic-sea-ice.net/index.php/topic,434.0.html

dnem

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Re: The Holocene Extinction
« Reply #498 on: July 30, 2020, 08:09:50 PM »
Since the bears are known to travel large distances for food and are not territorial, the theory is that they will simply move to optimal hunting grounds.  Speculation is that Greenland and the Canadian archipelago would be the top choice, as ice remains there year-round, and melting could open up more water holes.  The issue would then become how many bears the area could support.

This would also result in the local/regional extirpation of many polar bear populations.

kinbote

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Re: The Holocene Extinction
« Reply #499 on: July 30, 2020, 11:49:12 PM »
While "walking hibernation" was speculated as a possible state for polar bears in the early 1980's, some specialists have moved away from that conjecture in recent years.

https://polarbearsinternational.org/news/article-polar-bears/polar-bear-questions-do-polar-bears-undergo-walking-hibernation/

I think the conclusion is best summarized in the 2012 paper: “…we recommend that the term ‘walking hibernation’ not be used to describe summer–fall fasting in polar bears as it implies greater energy conservation than actually occurs.”

It would be great to have a polar bear study that examined the blood urea/creatinine ratio as well as body weight, as this would allow a deeper understanding of the physiological dynamics happening inside a starving bear. However, all evidence points to the fact that polar bears possess no special trick to help them survive lengthy periods without food. Instead, they lose weight just like any other starving mammal. To survive long-term, polar bears need a good platform of sea ice from which to hunt seals. In short: no sea ice = no polar bears.