We're on course for the sixth mass extinction event - Politics Forum.org | PoFo

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#14846398
Unlike the comet striking the Yucatan, this will likely be a slow-motion (at least in human terms) mass extinction.

http://www.newsweek.com/meade-prophecy- ... sor-669892

Daniel Rothman, a geophysict at the Massachusetts Institute of Technology, compiled a database of information about previous mass extinctions and major environmental changes. After analyzing the data, he boiled it down to a (deceptively) simple equation and a number: the amount of carbon that would be required—if added over a short period of time—to throw the carbon cycle out of whack.

That threshold is about 310 gigatons of extra carbon in the oceans. Earth will likely hit that critical amount by 2100...


The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. It's a homeostatic system that is able to absorb a lot of changes in its input factors and remain stable...but there are limits.

Rothman noted that every previous mass extinction event was preceded by a disruption in the carbon cycle. The problem with this indicator, however, is that not every disruption in the carbon cycle led to an extinction event. Rothman's study was designed to separate what carbon cycle disruptions that lead to extinctions from those that don't. The object, of course, is a more robust indicator for predicting mass extinction events.

He hypothesized that the rate of change of carbon addition was the differentiating factor. If true, then a mass extinction event would be triggered by 1) adding a threshold amount of carbon, and 2) doing so in a short amount of time. So there would be two actual trigger thresholds to pass: absolute amounts of carbon, and rate of change of carbon addition.

Using the formula he developed by backtesting against historical data, he concluded that 310 extra gigatons of carbon in the oceans by 2100 would be a valid trigger.

There are some major caveats to the paper. The paper doesn't identify any mechanisms for how reaching that threshold would lead to a mass extinction event; the carbon cycle could just be a related indicator, not a cause, of a mass extinction. And the data came from records gathered from many other sources, which introduces some imperfections and forms of bias.


He also noted that it would take a period of 10,000 years for all these changes to unwind fully. It's unclear if this process can be reversed, once it is triggered.
#14846634
quetzalcoatl wrote:Unlike the comet striking the Yucatan, this will likely be a slow-motion (at least in human terms) mass extinction.

The sixth mass extinction event has been underway for some tens of thousands of years, and it is definitely our doing, but CO2 is not even relevant. First we extinguished many species of terrestrial megafauna by hunting and eating them. Others we extinguished by out-competing them for food and other resources. Others we extinguished because they threatened us. That was when we were still hunter-gatherers and nomadic herders. Then once we started farming, we permanently altered large ecosystems, extinguishing many species by removing their habitats. Then we started unsustainable large-scale exploitation of marine species, extinguishing many. But by far the most extinctions have been caused by our transportation systems. Isolation drives speciation, and the effective ending of ecological isolation by modern transportation systems, with the associated uncontrollable introduction of invasive species from other biomes, means that competition for resources has greatly intensified. It is virtually certain that millions of species have been or will be lost to competition from invaders introduced accidentally by our transportation systems. And there is no reason to think it is any kind of tragedy.
#14854077
@Truth To Power,
Not entirely accurate, the sixth mass extinction refers to human activity after the industrial revolution. More precisely, from the year 1900 up to date.
Obviously, species have become extinct in any period of time, but in the last 150 years at a much faster pace than what is considered 'normal' according to the laws of natural selection.
For example, if you look at the distrubution of megafauna in 1900 and in 2017, you'll see that almost all species have dwindled considerably in numbers.
Take for example large carnivores, or large herbibores for that matter.

In the case of megafauna, the reasons are many, but the massive production of hunting tools and fire-arms, the demographic explosion of humans and the destruction of habitat seem to be the central causes.

In the case of many smaller animals like frogs, it's more difficult to assess the causes, though it's also happening and it's also related to human activity. :(

And well, your claim that there's no reason to think of it as a tragedy...speak for yourself.
Even solely from the aesthetical viewpoint, I think it'd be a tragedy to lose the tiger for example :*(

Of course there are also logically funded enviromental reasons why the massive extinction of species is detrimental to humans, since the dangers of destabilising the ecosystem are quite difficult to predict...

More info about it in this article:
https://www.theguardian.com/environment/2017/jul/10/earths-sixth-mass-extinction-event-already-underway-scientists-warn
#14854105
And well, your claim that there's no reason to think of it as a tragedy...speak for yourself.
Even solely from the aesthetical viewpoint, I think it'd be a tragedy to lose the tiger for example :*(

Actually, objectively speaking, Truth to Power is correct. Nature couldn't care less one way or the other. Nature, after all, is not a person and feels nothing about anything, and is therefore indifferent to the fate of life on Earth. It is we who care, partly for aesthetic reasons and partly for practical reasons. If a sixth extinction event is underway (and it looks very much as though it is), we will likely be caught up in it and will suffer from the progressive deterioration of our environment and the impoverishment of many of the natural and biological resources on which our civilisation depends. That's a tragedy for us, but Mother Nature will just continue blithely on her way as though nothing has happened. Once humanity goes extinct in a few millions of years time, the world's ecosystem will slowly recover from our depredations and new species and new biodiversity will replace the old, lost species. As Kurt Vonnegut put it in Slaughterhouse 5, "So it goes...."
#14854159
Potemkin wrote:Actually, objectively speaking, Truth to Power is correct. Nature couldn't care less one way or the other. Nature, after all, is not a person and feels nothing about anything, and is therefore indifferent to the fate of life on Earth. It is we who care, partly for aesthetic reasons and partly for practical reasons. If a sixth extinction event is underway (and it looks very much as though it is), we will likely be caught up in it and will suffer from the progressive deterioration of our environment and the impoverishment of many of the natural and biological resources on which our civilisation depends. That's a tragedy for us, but Mother Nature will just continue blithely on her way as though nothing has happened. Once humanity goes extinct in a few millions of years time, the world's ecosystem will slowly recover from our depredations and new species and new biodiversity will replace the old, lost species. As Kurt Vonnegut put it in Slaughterhouse 5, "So it goes...."


Well, I have a question for you then. I take an equally pessimistic view of the future: the logical, rational thing would be for capitalists to find profitability in energy technology that carries much less destructive capability than hydrocarbon emissions so that we don't accelerate our own (or near) extinction, but the response is less than lukewarm, at the very best. Unless people begin to colonize the solar system within the next century, I don't see things getting any better for the continuation of our species. You and I both know there is no sky king deity ready to step in when we destroy our world's capacity to support us.

However, do you think we won't establish off-world colonies? There's always the possibility of Earth experiencing a terminal event, where any off-world colonies thus can't feasibly support themselves and the human race effectively ends at that point, or armed conflict that could lead to destruction of such colonies, but you don't think that if we establish colonies off-world, humanity's survival is essentially assured? Basically, do you envision everything going tits up?
#14854165
@Bulaba Jones Everything considered, life on an environmentally devastated earth would still be less challenging than life on Mars or a space colony. Especially if you're talking about long-term survival.
#14854183
Sure. Earth is not a long-term solution, however. If we stay on Earth, our extinction is guaranteed.

Our extinction is guaranteed anyway, Bulaba. It's only a question of when, not if. Either our clade will die out entirely, leaving no descendants (which is the fate of most species), or we will evolve into something we ourselves would not recognise as being human. Either way, we in our present form are doomed. But this will likely take several million years to play out, even if we do collapse the Earth's ecosystem in our wild 'teenage' years, as looks increasingly likely. Currently, we're like a bratty teenage kid who has taken his dad's Maserati for a spin while high on coke and is just about to run it off the road and total it on a tree. It's not necessarily the end of our species' existence, but we're likely going to be grounded for the next ten or twenty thousand years. Lol.

As for the Earth not being a long-term solution, you are right. But the Earth is good for another 500 or 600 million years, until it becomes inhospitable for macroscopic life. Given the fact that the average life-span of a species is somewhere between 10 million and 20 million years, this is not something which need concern us. We won't be around that long. Either we will go extinct, like about 99% of all species which have ever lived, or we will evolve into something we ourselves would not recognise or acknowledge as being human. No, for better or for worse, the Earth is our home and there is no better place for us to be. As Robert Frost so wisely said:
Robert Frost wrote:I'd like to get away from earth awhile
And then come back to it and begin over.
May no fate willfully misunderstand me
And half grant what I wish and snatch me away
Not to return. Earth's the right place for love:
I don't know where it's likely to go better.
#14854576
It's ironic that coal miners used to take canaries with them, whose deaths would warn them of deadly gases but today we watch species after species go extinct and fail to make the connection to our own health.

I'm more concerned with our civilisation collapsing than with our species going extinct. When the Earth becomes too polluted to sustain wildlife its capacity to sustain human life will be greatly diminished and we will likely witness a rapid downsizing of society as famine, war and mass migrations overwhelm us.
#14855000
Those in power won't care, they will simply retire to the bunkers where every imaginable luxury has been stockpiled for them. They probably eat Dodo burgers there and everything. It will be like London but the people will be even more insuferable.
#14892749
Oxymoron wrote:Its a fucking Bear get over it..


Uh-Uh.................... it's a helluva lot more than a bear. Maybe if you stare at for a few years you will start to get it.
#14892751
Its a fucking Bear get over it..

Spoken like Mother Nature herself, Oxy. ;)

As I keep saying, Mother Nature don't give a fuck about polar bears, or indeed about us. And that cute white bear would eat your fucking face, if you gave it the chance. No, we should care about climate change because of the effect it's going to have on us, and on our descendants. That stranded polar bear will probably starve, but that's not important in and of itself (except to the polar bear, obviously). However, it is important as a symptom of the way that we're fucking up our environment, on which we depend for our physical existence. And that's not good. :hmm:
#14892827
I hate to say it but this civilisation is fucked. Either the planet will cleanse itself through some natural or cosmic event or maybe we'll do it to ourselves. Then what's left of humanity will quickly regain the knowledge of the past and use its vast resources to leave this rock and colonise the stars.

We're too set in our ways to make a drastic change before it's too late. We have the ability and the intellect but we still need a catalystic event to reboot our mindset.

Of course this is just speculation and it's never too late but time is ever fleeting.
#14892841
jessupjonesjnr87 wrote:I hate to say it but this civilisation is fucked. Either the planet will cleanse itself through some natural or cosmic event or maybe we'll do it to ourselves. Then what's left of humanity will quickly regain the knowledge of the past and use its vast resources to leave this rock and colonise the stars.

We're too set in our ways to make a drastic change before it's too late. We have the ability and the intellect but we still need a catalystic event to reboot our mindset.

Of course this is just speculation and it's never too late but time is ever fleeting.

People only do stuff if they have to. Change only arises out of necessity. Unfortunately, by the time something becomes necessary, it's usually too late. :hmm:
#14892863
SolarCross wrote:Polar Bears can swim for hundreds of miles at a time. Your heart is breaking for nothing.

Indeed, but they hunt on ice, not while swimming. Reduce the ice cover too much, and they starve. Which is not a problem in and of itself, of course - animals starve to death on a regular basis, and species have been going extinct for billions of years. The problems arise from the current rate of climate change and extinction. This could have severe consequences for ourselves.
#14893913
Potemkin wrote:.... or we will evolve into something we ourselves would not recognise as being human.


It may be more likely we'll be replaced by our own machine creations including possibly, androids. The latter might at least outwardly resemble us. :)

But the Earth is good for another 500 or 600 million years, until it becomes inhospitable for macroscopic life.


Because of old sol leaving main sequence...But it may be possible to prolong terrestrial habitability by means of solar shades or something, for considerably longer.

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