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Under a Green Sky
I don't completely subscribe to Ward's conclusions in his book _Out of
Thin Air_ concerning dinosaurs, mammals and oxygen levels... but his
most recent book, _Under a Green Sky_, in my humble opinion, is right
on the money.
All of the work I've been doing lately in climate science (Arctic
climate change, in particular) pretty much hammers home his book's
message.... especially when you consider the second article I have
copied below which is about a study recently published in the
Proceedings of the Royal Society B, and which also discusses an
additional study that was presented by Ward at GSA's meeting in Denver
a few weeks ago. The gist of it is that there is a natural 60
million-year cycle of climate that moves between warm and cool periods.
Right now, the current state of the climate follows suit as it warms
from its recent glacial state. If these studies holds true, then we are
on track to see the same level of extinctions brought about by climate
warming in the past sometime in the next 100 years, unless greenhouse
gas emissions are curbed, and curbed fast. What's interesting is that
this is nearly the same conclusion announced yesterday by the
Nobel-Prize winning U.N. scientific panel which met in Spain last week.
It's interesting how over the past couple of years, the climate
modeling community has become less skeptical about just how bad
conditions were, for example, 250 mya, even though the evidence is
clearly laid out in the rocks. Climate models have become sophisticated
enough to reproduce past climate systems with enough fidelity to
re-create conditions like those seen preserved in the rocks... even for
those conditions that defy belief as in severe greenhouse worlds which
cooked the planet 4 times over the past 520 million years.
Of course, how can you trust models of past and future climate if the
models of current climate can't get it right? Well, here's the thing...
models of current climate DO get it reasonably right. They are not as
far out to lunch as the media would lead you to believe. And speaking
from my own personal experience, the main problem for climate change
models is one of temporal resolution. And by that I mean, the changes
in the current climate system that we are seeing are produced, but not
soon enough; e.g. ALL models forecast Arctic ice loss, but not as fast
as the observed conditions. They lag by an average of 50-100 yrs.
In the grand scheme of things... that is pretty freakn' scary.
Global Warming Linked to Worst Mass Extinctions in Earth History
By Rosanne Skirble
09 October 2007
A new book explores how global warming is linked to the worst mass
extinctions in earth's history. In Under a Green Sky, paleontologist
Peter Ward recounts how a sharp CO2 rise accelerated dramatic
environmental changes in the past, and what that can tell us about our
future. Rosanne Skirble reports.
Picture this: "Shorelines encrusted with rotting organic matter. From
shore to horizon â as far as the eye can see there is an unending
purple color, a vast flat oily purple. We are under a pale green sky,
and it has the smell of death and poison."
This is a scene from the book Under A Green Sky: Global Warming, the
Mass Extinctions of the Past and What They Can Tell Us About Our
The author, Peter Ward, has spent a career studying fossils. He
specializes in catastrophic mass extinctions from the earth's ancient
past â what scientists call the 'Big Five.' "[Those] that killed off at
least 50 percent of the species on earth, and one of them, the Permian,
may have killed off 90 percent of the species on earth," he explains.
Ward, a University of Washington paleontologist, details the causes and
consequences of these events in Under A Green Sky. He says most
scientists embrace the idea that a giant asteroid hit the earth around
65 million years ago, hastening the demise of the dinosaurs. He
describes the earth as it goes through a global blackout. "We have
falling meteors coming back from the impact sites setting all the
forests on fire. We have sulfur going into the atmosphere coming back
as sulfuric acid, acidifying the ocean, acid rain in the lakes."
But asteroids do not explain the other mass extinctions. For that, Ward
and others have found evidence in the fossil record that prolonged
volcanic activity spewed huge amounts of carbon dioxide and other gases
into the atmosphere. As he points out, "There was a short-term rapid
increase in carbon dioxide. High C02 increases greenhouse temperatures
on the planet."
Over thousands of years, that spike in CO2 and the resulting worldwide
heat wave had nasty consequences. Winds ceased, ocean currents died and
most marine life vanished from too much heat and too little oxygen.
Ward says things got even worse. "These warm anoxic oceans produced
[surface] blooms of hydrogen sulfide-producing bacteria. Enough of that
went into the atmosphere to kill land animals and land plants and cause
the ozone to disappear as well."
Records show that environmental change began to accelerate when
atmospheric CO2 hit 1,000 parts per million. Today's levels are
one-third of that and rising.
Looking at the ancient evidence, Ward notes that ice caps began to
shrink. "Melting all the ice caps causes a 75-meter increase in sea
level. [That] will remove every coastal city on our planet." It will
also cover earth's most productive farmland, the author warns, adding,
"It will happen if we do not somehow control CO2 rise in the
Ward does see some positive signs in the fight against global warming.
"Most people are now educated as to what it is and most everyone knows
that it has to do with carbon dioxide and that we have to slow that
down. There is half the battle right there."
Ward is also encouraged that people are beginning to make changes in
their daily lives and demanding action from their leaders. He hopes his
book helps readers put the current state of the earth into historical
perspective. "[Recognizing] that we are on a planet that has violent
convulsions, and that we humans are playing with nature in such a way
that we could recreate what were some really awful times in earth's
history, that we really tinker with the earth's atmosphere at our
As Peter Ward writes in Under a Green Sky, "This moment on this Earth
truly is a precious gift, to be savored and appreciated. If we
needlessly destroy this world, it is unlikely we will find another to
Wednesday, October 24, 2007 - Page updated at 01:04 AM
Mass-extinction study casts cloud on future
By SETH BORENSTEIN
The Associated Press
WASHINGTON â Whenever the world's tropical seas rose several degrees,
Earth experienced mass extinctions over millions of years, according to
a first-of-its-kind statistical study of fossil records.
And scientists fear it may be about to happen again â but in a matter
of several decades, not tens of millions of years.
Four of the five major extinctions over 520 million years of Earth
history have been linked to warmer tropical seas, something that
indicates a warmer world overall, according to the new study published
"We found that over the fossil record as a whole, the higher the
temperatures have been, the higher the extinctions have been," said
University of York ecologist Peter Mayhew, co-author of the
peer-reviewed research published in the Proceedings of the Royal
Society B, a British journal.
Earth is on track to hit that same level of extinction-connected
warming in about 100 years, unless greenhouse-gas emissions are curbed,
according to top scientists.
A second study, to be presented Sunday, links high carbon-dioxide
levels, the chief man-made gas responsible for global warming, to past
extinctions. The study was conducted by a University of Washington
In the British study, Mayhew and his colleagues looked at temperatures
in 10 million-year chunks because fossil records aren't that precise in
time measurements. They compared those to the number of species, the
number of species families, and overall biodiversity. They found more
biodiversity with lower temperatures and more species dying with higher
The researchers examined tropical-sea temperatures â the only ones that
can be determined from fossil records and go back hundreds of millions
of years. They indicate a natural 60 million-year climate cycle that
moves from a warmer "greenhouse" to a cooler "icehouse." The Earth is
warming from its current colder period.
Every time the tropical-sea temperatures were about 7 degrees warmer
than they are now and stayed that way for enough years, there was a
The study linked mass extinctions with higher temperatures but did not
try to establish a cause and effect. For example, the most recent mass
extinction, the one 65 million years ago that included the die-off of
dinosaurs, probably was caused by an asteroid collision as scientists
theorize and Mayhew agrees.
But extinctions were likely happening anyway as temperatures were
increasing, Mayhew said. Massive volcanic activity, which releases
large amounts of carbon dioxide, has also been blamed for the dinosaur
The author of the second study, which focuses on carbon dioxide, said
he sees a cause and effect between warmer seas and extinctions.
Peter Ward, a University of Washington biology and paleontology
professor, said natural increases in carbon dioxide warmed the air and
ocean. The warmer water had less oxygen and spawned more microbes,
which in turn spewed toxic hydrogen sulfide into the air and water,
Ward examined 13 major and minor extinctions in the past and found a
common link: rising carbon-dioxide levels in the air and falling oxygen
levels. Ward's study will be presented Sunday at the Geological Society
of America's annual convention in Denver.
Mayhew also found increasing carbon-dioxide levels in the air
coinciding with die-offs.
Those higher temperatures that coincided with mass extinctions are
about the same level forecast for a century from now if the world
continues its growing emissions of greenhouse gases, according to the
Intergovernmental Panel on Climate Change.
In April, the same climate panel of thousands of scientists warned that
"20 to 30 percent of animal species assessed so far are likely to be at
increased risk of extinction" if temperatures rise by about 3 to 4
"Since we're already seeing threshold changes in ecosystems with the
relatively small amount of climate change already taking place, one
could expect there's going to be severe transformations," said
biologist Thomas Lovejoy, president of the H. John Heinz Center for
Science, Economics and the Environment in Washington, D.C.
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