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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.

Kris
Saurierlagen@gmail.com

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Global Warming Linked to Worst Mass Extinctions in Earth History
By Rosanne Skirble
Washington, DC
09 October 2007

http://www.voanews.com/english/archive/2007-10/2007-10-09-voa24.cfm?CFID=221110350&CFTOKEN=19133481

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 Future.

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 atmosphere."


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 peril."

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 replace it."

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Wednesday, October 24, 2007 - Page updated at 01:04 AM

http://seattletimes.nwsource.com/html/nationworld/2003970889_extinctions24.html

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 today.

"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 scientist.

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 temperatures.

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 die-off.

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 extinction.

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, killing species.

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 degrees Fahrenheit.

"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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