Sixth mass extinction has begun

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Beaver
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Sixth mass extinction has begun

Postby Beaver » Thu Nov 01, 2018 4:45 pm

Humanity has wiped out 60% of animal populations since 1970, report finds
The huge loss is a tragedy in itself but also threatens the survival of civilisation, say the world’s leading scientists
https://www.theguardian.com/environment ... port-finds

"Humanity has wiped out 60% of mammals, birds, fish and reptiles since 1970, leading the world’s foremost experts to warn that the annihilation of wildlife is now an emergency that threatens civilisation. The new estimate of the massacre of wildlife is made in a major report produced by WWF and involving 59 scientists from across the globe. It finds that the vast and growing consumption of food and resources by the global population is destroying the web of life, billions of years in the making, upon which human society ultimately depends for clean air, water and everything else.

“We are sleepwalking towards the edge of a cliff” said Mike Barrett, executive director of science and conservation at WWF. “If there was a 60% decline in the human population, that would be equivalent to emptying North America, South America, Africa, Europe, China and Oceania. That is the scale of what we have done.” “This is far more than just being about losing the wonders of nature, desperately sad though that is,” he said. “This is actually now jeopardising the future of people. Nature is not a ‘nice to have’ – it is our life-support system.”

“We are rapidly running out of time,” said Prof Johan Rockström, a global sustainability expert at the Potsdam Institute for Climate Impact Research in Germany. “Only by addressing both ecosystems and climate do we stand a chance of safeguarding a stable planet for humanity’s future on Earth.” Many scientists believe the world has begun a sixth mass extinction, the first to be caused by a species – Homo sapiens. Other recent analyses have revealed that humankind has destroyed 83% of all mammals and half of plants since the dawn of civilisation and that, even if the destruction were to end now, it would take 5-7 million years for the natural world to recover."

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Re: Sixth mass extinction has begun

Postby Henry Vilas » Thu Nov 01, 2018 4:50 pm

This story belongs here.

Beaver
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Re: Sixth mass extinction has begun

Postby Beaver » Fri Nov 02, 2018 8:56 am

I post too much there, and most of it is ignored. I wanted to highlight this more.

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Re: Sixth mass extinction has begun

Postby gargantua » Fri Nov 02, 2018 9:25 am

Beaver wrote:I post too much there, and most of it is ignored. I wanted to highlight this more.

I agree. Plus I always thought the other thread was a bit tongue-in-cheek. Along with everything else we're doing to the environment, this is a critical issue. As a species, the human race is just merrily going along as if we're not a part of the ecosystem we're destroying. It could very well collapse before our technology can save us. If that was even possible.

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Re: Sixth mass extinction has begun

Postby Ned Flanders » Fri Nov 02, 2018 10:00 am

I caused a mass extinction in the bathroom last night. No more Taco Bell.

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Re: Sixth mass extinction has begun

Postby JoeT » Fri Nov 02, 2018 10:55 am

Many scientists believe the world has begun a sixth mass extinction, the first to be caused by a species – Homo sapiens.

The statement is questionable in that around 2.5 billion years ago cyanobacteria pumped oxygen into the atmosphere that caused anaerobic bacteria to die off. Perhaps the distinction the author is making is that this particular extinction isn't classified as among the 5 major extinction events since the only life that existed at that time was very primitive. However, among the five major events, the early Devonian extinction is sometimes attributed to early land plants which drew down CO2 from the atmosphere. Here's a short video about cyanobacteria.

You'll notice one thing that is somewhat peculiar and is mentioned in the video. The claim is that the oxygen pumped into the atmosphere by cyanobacteria reacted with methane to form carbon dioxide. Since carbon dioxide is a weaker greenhouse gas than methane the planet cooled, initiating the Huronian glaciation. That methane is a stronger greenhouse gas than carbon dioxide during this glaciation isn't obvious at all. It depends on the relative concentration of the two gases. Methane is a stronger greenhouse gas now because there is so much less of it in the atmosphere than CO2. That is, adding 1 additional molecule of methane now has a much larger warming effect than if you added 1 more molecule of CO2. But if you had equal concentrations, CO2 is a stronger greenhouse gas.

About a year ago, there was a fascinating article published by an MIT professor about the possibility of a sixth major extinction event. He did something I thought was very clever which was to consider that past extinction events were due to changes in the carbon cycle. He then calculated how much additional carbon to the world's oceans might trigger the next extinction event. His conclusion wasn't very reassuring.
The IPCC projections consider four possible pathways for carbon dioxide emissions, ranging from one associated with stringent policies to limit carbon dioxide emissions, to another related to the high range of scenarios with no limitations. The best-case scenario projects that humans will add 300 gigatons of carbon to the oceans by 2100, while more than 500 gigatons will be added under the worst-case scenario, far exceeding the critical threshold. In all scenarios, Rothman shows that by 2100, the carbon cycle will either be close to or well beyond the threshold for catastrophe.

Mathematics predicts a sixth mass extinction
His paper is better than the summary linked to above.

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Re: Sixth mass extinction has begun

Postby Henry Vilas » Tue Jan 01, 2019 6:48 pm

These species went extinct in 2018. More may be doomed to follow in 2019.

Earth "is now in the midst of its sixth mass extinction of plants and animals – the sixth wave of extinctions in the past half-billion years," according to the Center for Biological Diversity.

The group said "we're currently experiencing the worst spate of species die-offs since the loss of the dinosaurs 65 million years ago.

"Although extinction is a natural phenomenon, it occurs at a natural “background” rate of about one to five species per year. Scientists estimate we're now losing species at 1,000 to 10,000 times the background rate."

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Re: Sixth mass extinction has begun

Postby Bwis53 » Tue Jan 01, 2019 7:46 pm

Yeah, but we won't be there...

I always thought we were an invasive species, just like those in Independence Day.

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Re: Sixth mass extinction has begun

Postby Ducatista » Wed Jan 02, 2019 12:40 pm

JoeT wrote:Perhaps the distinction the author is making is that this particular extinction isn't classified as among the 5 major extinction events since the only life that existed at that time was very primitive.

I'm guessing the distinction is more like: the other extinctions weren't knowingly and willfully caused by a species.

We're the first assholes to understand the havoc we're wreaking and keep on doing it.

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Re: Sixth mass extinction has begun

Postby gargantua » Wed Jan 02, 2019 5:08 pm

Ducatista wrote:
JoeT wrote:Perhaps the distinction the author is making is that this particular extinction isn't classified as among the 5 major extinction events since the only life that existed at that time was very primitive.

I'm guessing the distinction is more like: the other extinctions weren't knowingly and willfully caused by a species.

We're the first assholes to understand the havoc we're wreaking and keep on doing it.

My guess is that the majority of people DON'T understand it, at least not beyond a very superficial level. I was thinking about this recently, with respect to how much the world has changed in just the six decades that I remember. Younger people have no idea what they've already lost. Other than for written accounts, I don't have the experience of what the natural world was like before I was born. It's too abstract for most people, for whom the world seems pretty much the same from one day to the next. I'd argue that we're doing it more out of willful ignorance than malevolence.

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Re: Sixth mass extinction has begun

Postby Paleo2 » Sun Jan 06, 2019 8:08 am

At what point do we consider the beginning of the anthrogenic sixth extinction?

Is it at the end of the last ice age, when humans hunted much of the megafauna to extinction? Or does that count because those species were adapted to a climate which had changed?

Is it when humans wipes out the passenger pigeons and dodos?

Or do we start the clock when humans greatly modified the environment at the dawn of civilization?

Or does the extinction begin with the Indistrial Age?


Compared to the age of the earth, and how long most eons last, this is fairly trivial. But an interesting point.

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Re: Sixth mass extinction has begun

Postby gargantua » Sun Jan 06, 2019 10:31 am

I think the choice of any particular moment is a subjective value judgement. Mine would be the dawn of the human race. To me, that's what started the process.

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Re: Sixth mass extinction has begun

Postby Cadfael » Sun Jan 06, 2019 12:39 pm

gargantua wrote:I think the choice of any particular moment is a subjective value judgement. Mine would be the dawn of the human race. To me, that's what started the process.

Now all we have to do is agree on exactly when that was. :D

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Re: Sixth mass extinction has begun

Postby Henry Vilas » Tue Jan 08, 2019 7:36 pm

Lonely George the tree snail dies, and a species goes extinct

When one dies, it is a tragedy. When a million die, it is a statistic.
Attributed to Iron Joe

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Re: Sixth mass extinction has begun

Postby Bwis53 » Tue Jan 08, 2019 9:41 pm

A conspiracy theory I've heard is, that the overlords want to "depopulate" the earth...


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