Sixth Mass Extinction Underway

[Sssith]

Not really surprising that this argument is being made. 

http://www.cnn.com/2017/07/11/world/sutter-mass-extinction-ceballos-study/index.html

http://www.biologicaldiversity.org/programs/biodiversity/elements_of_biodiversity/extinction_crisis/

[Cluck Kent]

But what does it all mean? Extinction is part of evolution is it not? And while I won't argue that man (and woman) is impacting climate change and polluting the earth which likely contributes to the extinction of various species, I have no sense of the historical context of what is happening today and how that compares with what has happened during the last 4.5 billion years the earth has been around.

Sounds awful, very doomsdayish. But is it? I have no idea.

[Reigns]

Well, it is very doomsdayish.
That's why they call it a mass extinction.

[TheMikrobe]

But what does it all mean? Extinction is part of evolution is it not? And while I won't argue that man (and woman) is impacting climate change and polluting the earth which likely contributes to the extinction of various species, I have no sense of the historical context of what is happening today and how that compares with what has happened during the last 4.5 billion years the earth has been around.

Sounds awful, very doomsdayish. But is it? I have no idea.

I've heard about "a new mass extinction" for a few years, so I guess there is new data to bring it back into the news.

Extinctions have always occured and new species evolved, but I think the point is that the current rate of environmental change is abnormally high and extinctions are occuring at a much greater rate than at most times in the past. That means that evolution can't keep up so biodiversity decreases. Also the environment is homogenised and controlled, e.g. fewer forests and more farmland, meaning the Earth can't support as many species even given time for them to evolve into the new environments. A real problem talking politically about it is that even when the change is "abnormally high" it is still not very noticeable on the scale of a single human lifetime, so as you note it is hard to get a sense of the historical context (and leaves predictions open to counter-arguments).

[Darkness]

Extinctions have always occured and new species evolved, but I think the point is that the current rate of environmental change is abnormally high and extinctions are occuring at a much greater rate than at most times in the past. That means that evolution can't keep up so biodiversity decreases. Also the environment is homogenised and controlled, e.g. fewer forests and more farmland, meaning the Earth can't support as many species even given time for them to evolve into the new environments. A real problem talking politically about it is that even when the change is "abnormally high" it is still not very noticeable on the scale of a single human lifetime, so as you note it is hard to get a sense of the historical context (and leaves predictions open to counter-arguments).

Mik has nailed it here.

Previous mass extinctions have taken place over hundreds of thousands millions of years. The non-avian dinosaurs weren't wipe out overnight. The great oxygenation event (which made life possible for us but screwed over all the CO2 breathers) was a long term piece of work.

What we're talking about here is an exintction event over a much shorter timeframe of a few thousand of years, where the cause of the extinctions is being driven by rapid changes to the environment which outpace adaptation of organisms at a species level. In terms of the history of mass extinction events, humanity is without precedent in what we're doing and how we do it.

Also, Hi.

[Orbert]

Darkness!