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Anthropocene

 

This month the Museum asks, “Are we in the Anthropocene?”

“The Anthropocene is a proposed epoch dating from when human activities started to have a significant global impact on Earth's geology and ecosystems”. Is this Long Term Global Warming or maybe just another Dansgaard-Oeschger event? The 19th Mass Extinction?

 But the great thing about another mass extinction is that if human populations become isolated again, and this can be on Mars as well as Earth, it should kick off evolutionary pressures and as Handel nicely put it “we will be changed”.  Neanderthals, Devonians, we have shared our world with “cousins” in the past and in an isolated population can have them again.


It should also be noted that Mars is not habitable, or terraformable on a large scale, nor with current science can it be made so. It has a limited magnetic field, not like the protection we have on Earth from the solar winds. It is very cold and because of the thin atmosphere, and the lack of liquid water, it does not hold the heat it receives. The average temperature is 70 below, although in direct sunlight in summer it can get well into the aboves, until night falls. Even if you melted the icecaps, somehow, it would only raise the temperature a few degrees and would not bring about a Greenhouse effect. Plus without biology now, the soil will be basically sterile, we will have to transport and create the ingredients to make it grow Earth plants. No fossil fuels, we’ll need alternate energy sources. And if any of the life-supporting system breaks down, you just can’t get in your Ford Pickup and drive away from New-Oklahoma. You are dead. Mars is not a “the Grapes of Wrath” scenario, and most certainly not a panacea, nor can we make it one.


However, the Museum is sure we will try to tamper with the human genome. Evolution has to use existing material to make changes and there are many unexpected consequences along the way. Imagine how we will do being able to put New genes into the system. We will be changed.

When looking at the 5 big extinctions, a common thread in them all is problems in the oceans. Water covers about 70% of our planet’s surface, so it’s not something you should mess with. It also stores heat remarkably well which is often forgotten when we talk of global warming. You can prove this at home; fill a water balloon and put it over an open flame and see what happens. Spoiler alert, the balloon does not break. Most of that global warming is going into the oceans, and even if we are in another D-O event the oceans will continue to be warm, and our ice sheets to melt, into the next century. The museum again recommends that you do not buy ocean front property unless you like to fish from the 2nd story windows. Another nifty thing is that as the oceans absorb carbon dioxide they also get more acidic. Bottom line is; if and when the oceans change, life changes with them. Science should be able to save a few select pockets of humanity but the overall population will shrink dramatically.

Extinctions filter out diversity and then life flourishes starting from a few remaining genomes.

 The Big five in mass extinctions:

End Ordovician, 444 million years ago, 85% of species lost:

Late Devonian, 375 million years ago, 75% of species lost:

End Permian, 251 million years ago, 95% of species lost: This is the big one. But Species lost is not life loss, just diversity loss. Bacteria, Viruses, these survive and if called on can start the diversity all over again. This extinction brought in the age of the Dinosaurs.

End Triassic, 200 million years ago, 80% of species lost: But the Dinosaurs survived this one.

End Cretaceous, 66 million years ago, 75% of all species lost: And this is the one that allowed “us”, the mammals, to flourish as the Dinosaurs, with the exception of birds, died off.  Along with that it is also the museums favorite because this one was a real Wrath of God event complete with a huge asteroid and massive volcanic explosions on top of everything else.

In general the Earth has been much warmer than it is now, there were no polar icecaps in the Cretaceous, but we evolved in the current Ice Age and there is no guarantee we can survive in any other type of climate. Science should see us through the Anthropocene mass extinction, but like Neanderthal before us our line might go extinct and Homo will then continue as a yet to evolve Cousin.

There is some chance if we hit enough “tipping points” that the Earth will go full greenhouse, beyond where most life is sustainable naturally. Then we will be at the mercy of science and our artificial life supports. Tipping points, Points of no return, Points of inevitable consequences, we do not have the science now to tell where they are. We might never hit them, we might have crossed them all by now. But one thing is for sure, the natural world of our grandchildren will not be the one we are in now.


Unkwil



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Uncle Willie loves to have feedback from both readers who appreciate his point of view as well as from missguided souls who disagree.