As the saying goes,"God is no respecter of persons."
Posted by: "Lin Kerns" linkerns@gmail.com lin.kerns Date: Fri
Nov 18, 2011 6:22 pm ((PST))
True. And how old was your friend when he learned this? For those of us
who grew up surrounded by nature, we learned that the first time a tick
embedded in our skin or a catfish "spined" us at the river or we
accidentally ran our bikes over a yellow jackets' nest.
Lin
On Fri, Nov 18, 2011 at 2:37 PM, Robert Blau <robert-blau@webtv.net>
wrote:
**
A philosophical friend comments:
The human race thinks it is so important, but from the perspective of
the universe, who cares?
"Nature" is as indifferent as it is majestic or mysterious or terrifying
or any other quality that our minds can attribute to it.
Lin wrote:
Study details world's worst die-off: hell on Earth By Seth Borenstein AP
Science Writer / November 17, 2011
WASHINGTON—During the world's biggest mass
extinction, Earth seemed pretty close to a description of hell -- fiery,
smoky and explosive -- created by massive volcanic eruptions, according
to research dug up in China.
In geologic terms, it was surprisingly quick, and it may provide a scary
lesson about climate change for our future, authors of the new study
say. It was the third of five extinctions in world history, occurring
even before dinosaurs roamed.
This extinction killed off more than three-quarters of life on the
planet in an event scientists have called the Great Dying. The Chinese
dig sites provide new dates and details of the event, which occurred at
the end of the Permian Era. It happened 252 million years ago and may
have lasted less than 100,000 years, far shorter than scientists had
thought, according to the study published Thursday in the journal
Science.
The study also bolsters the prevailing scientific concept that the giant
die-off was caused by a massive shift in climate -- global warming,
prehistoric style -- triggered by volcanic activity that is far beyond
modern levels. The research also makes the case that the burst of carbon
dioxide and methane thrown into the atmosphere that triggered the
die-off took only about 20,000 years, less than previously thought,
though the ecological damage lasted longer.
And devastating fires raged worldwide, not just where the volcanoes
exploded, the paper said.
"Imagine drying out the Amazon and burning it up," said study co-author
Douglas Erwin, a paleobiology curator at the Smithsonian Institution.
"It certainly was a very uncomfortable time. You're killing off 75 to 90
percent of everything on the planet. It's not going to be terribly
pleasant."
The air at times could be like the thick smog outside an old Eastern
European power plant, Erwin said.
It was the only mass extinction in history to kill off hardy insects,
Erwin said. Afterward, there were very few species left worldwide, and
they had little diversity among different regions. It was only later
that dinosaurs and mammals roamed the Earth.
The study is based on more than two dozen cross-sections of soil, both
on land and under water, over thousands of miles in southern China. But
they should be representative of the entire world, given the shift of
continents over the past 250 million years, said lead author Shu-zhong
Shen of the Nanjing Institute of Geology and Paleontology. The study
also offered the first evidence that the die-off in the sea and on land
happened at the same time.
Erwin said the climate changed because of rapid infusions of carbon
dioxide and methane into the air. This study doesn't determine how much
it warmed, but other research has said temperatures rose by as much as 9
degrees Fahrenheit, making the climate at least 15 degrees warmer than
it is today.
Those greenhouse gases that trap heat probably were released because of
immense volcanic activity mostly in Siberia, he said. The eruptions --
probably hundreds of them lasting thousands of years -- spewed far more
carbon and magma than Earth has witnessed for tens of millions of years.
Just one such eruption would cover an area the size of Vermont, Erwin
said.
Outside experts had mixed reaction to the study.
Richard Twitchett of Plymouth University in Great Britain called it "an
excellent illustration of just how far we've come in getting to grips
with the greatest extinction event in the history of life on Earth."
But Luanne Becker, a former geochemist at the University of California
Santa Barbara, disagreed with Shen's conclusion about what caused the
global die-off. Becker is a longtime proponent of the minority view that
an asteroid or comet hitting Earth caused this extinction. She said that
while the study did a great job of defining what happened and how long
it lasted, "I do not feel that volcanism alone can trigger some of the
most catastrophic extinction events in the history of life on Earth.
Rather it would take multiple catastrophes to occur synchronously
(impact and volcanism) to trigger a mass extinction event," she wrote in
an email.
But Erwin said that despite global searches, scientists haven't found
signs of a comet or asteroid impact at the right time for this
extinction.
Shen theorized that environmental stress was building and then hit a
tipping point and "collapsed in a very rapid way." "This is also a
lesson for the modern times," Shen said. "We don't know what will happen
or when it will happen." This climate change "happened naturally, and it
killed everything," Erwin said. But he said that if critics of global
warming science think it shows that climate change is nothing to worry
about because it has happened naturally in the past, that's the wrong
conclusion.
"I think the lesson you take away from this is that you don't want to
get anywhere close to a mass extinction," Erwin said. "It took 5 million
years before life got better again."
------
source<
http://www.boston.com/news/science/articles/2011/11/17/study_details_worlds_worst_die_off_hell_on_earth/>
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