|
The important story below was originally posted a few years back; it covers a topic that should be in the back of everyone's mind. PBS also presented a 2-hour report on Earth's geological history which included prominently a description and explanation of the extensive Permian extinction of 250 million years ago.
The event is clearly measurable in fossil and sedimentary records, and a mass release of methane is one of the most negative risks that we face due to our human-boosted global warming. The accelerating release of methane gas is one of the "tipping points", or positive feedback loops, to which scientists refer. Here is the original article by geologist John Atcheson:
***************
Methane gas, abundantly trapped as a half-frozen slush in the northern hemisphere's tundra permafrost regions and at the bottom of the sea may well be a ticking time bomb, says geologist John Atcheson in an article published by the Baltimore Sun in December last year. Methane is about twenty times stronger as a greenhouse gas than carbon dioxide. Since arctic warming seems to procede faster than expected, there is a real danger that deposits of methane and similar gases trapped in normally frozen ground, may thaw out and "belch" into the atmosphere, wreaking havoc with our computer simulations of global warming.
According to Gregory Ryskin, associate professor of chemical engineering at Northwestern University, "explosive clouds of methane gas, initially trapped in stagnant bodies of water and suddenly released, could have killed off the majority of marine life and land animals and plants at the end of the Permian era" — long before dinosaurs lived and died. Ruskin believes that methane may have been the driving force in previous catastrophic changes of the earth's climate, where 95 percent of marine species and 70 percent of land species were lost in - geologically speaking - the blink of an eye.
You may ask "what can I do about this?". There are some suggestions in an article posted on the ZPEnergy site. Perhaps we should do everything possible to reverse the current trend towards global warming by burning less fossil fuels. The first target would be to go "carbon neutral", after which we should be figuring out ways to trap some of the excess carbon in the atmosphere and use it or store it in a non-gaseous form.
Using hydrogen instead of petroleum-derived fuels would be a first step, although we must find a way to produce the gas without burning more of the black stuff. Options range from the relatively inefficient direct-current electrolysis, solar hydrogen production at sea, the use of metal catalysts, high frequency electric currents, ultraviolet light and the action of bacteria which naturally produce hydrogen. It seems none of the technologies are quite ready to use, but there is no room for complacency.
Comes to mind the methane atmosphere that was recently found to be prevalent on Saturn's moon Titan. Could there be a point of break in the equilibrium of atmospheric composition where a celestial body's gas cover can switch from a predominantly nitrogen/oxygen composition to predominantly methane? If so, we better watch our steps because human bodies as well as most known animal species do not run on methane. We might be in for an unpleasant surprise.
John Acheson asks:
"How likely is it that humans will cause methane burps by burning fossil fuels? No one knows. But it is somewhere between possible and likely at this point, and it becomes more likely with each passing year that we fail to act.
So forget rising sea levels, melting ice caps, more intense storms, more floods, destruction of habitats and the extinction of polar bears. Forget warnings that global warming might turn some of the world's major agricultural areas into deserts and increase the range of tropical diseases, even though this is the stuff we're pretty sure will happen."
In what might have been an early warning, in 1986, Lake Nyos in Cameroon "burped" an amount of gases killing 1800 people, following a much smaller scale disaster on neighbouring lake Monoun two years earlier, which killed 37 people. While carbon dioxide has been fingered as the main culprit, there seems to have been a "fiery" component to the eruption indicating possible presence of combustible methane: "Skin discoloration found on some victims were tentatively interpreted as burns, but this diagnosis is still controversial. Witnesses on topographic highs report a loud noise originating from the lake and, in the case of lake Nyos, flashes of light visible over the lake".
Apparently, three dissolved gasses, carbon dioxide, hydrogen sulphide and methane come together and indeed, a project to recover the methane from the waters of Lake Kivu, on Rwanda's north-western border, is in advanced stage of engineering. A similar project is underway to de-gas lakes Nyos and Monoun in Cameroon.
While such isolated cases as the lakes in Africa may be amenable to direct engineering solutions, capturing the gasses and putting the methane to use as a fuel, we may not have such an easy solution ready for widespread methane outgassing from the warming of larger bodies of water and huge stretches of half-frozen tundra.
The only possible solution to stem the steady increase in atmospheric carbon dioxide would seem to satisfy our energy needs without burning hydrocarbons.
Ticking Time Bomb
John Atcheson
Baltimore Sun
15 Dec 2004
(sqwalk.com)
or
(commondreams.org)
The Arctic Council's recent report on the effects of global warming in the far north paints a grim picture: global floods, extinction of polar bears and other marine mammals, collapsed fisheries. But it ignored a ticking time bomb buried in the Arctic tundra.
There are enormous quantities of naturally occurring greenhouse gasses trapped in ice-like structures in the cold northern muds and at the bottom of the seas. These ices, called clathrates, contain 3,000 times as much methane as is in the atmosphere. Methane is more than 20 times as strong a greenhouse gas as carbon dioxide.
Now here's the scary part. A temperature increase of merely a few degrees would cause these gases to volatilize and "burp" into the atmosphere, which would further raise temperatures, which would release yet more methane, heating the Earth and seas further, and so on. There's 400 gigatons of methane locked in the frozen arctic tundra - enough to start this chain reaction - and the kind of warming the Arctic Council predicts is sufficient to melt the clathrates and release these greenhouse gases into the atmosphere.
Once triggered, this cycle could result in runaway global warming the likes of which even the most pessimistic doomsayers aren't talking about.
An apocalyptic fantasy concocted by hysterical environmentalists? Unfortunately, no. Strong geologic evidence suggests something similar has happened at least twice before.
The most recent of these catastrophes occurred about 55 million years ago in what geologists call the Paleocene-Eocene Thermal Maximum (PETM), when methane burps caused rapid warming and massive die-offs, disrupting the climate for more than 100,000 years.
The granddaddy of these catastrophes occurred 251 million years ago, at the end of the Permian period, when a series of methane burps came close to wiping out all life on Earth.
More than 94 percent of the marine species present in the fossil record disappeared suddenly as oxygen levels plummeted and life teetered on the verge of extinction. Over the ensuing 500,000 years, a few species struggled to gain a foothold in the hostile environment. It took 20 million to 30 million years for even rudimentary coral reefs to re-establish themselves and for forests to regrow. In some areas, it took more than 100 million years for ecosystems to reach their former healthy diversity.
Geologist Michael J. Benton lays out the scientific evidence for this epochal tragedy in a recent book, When Life Nearly Died: The Greatest Mass Extinction of All Time. As with the PETM, greenhouse gases, mostly carbon dioxide from increased volcanic activity, warmed the earth and seas enough to release massive amounts of methane from these sensitive clathrates, setting off a runaway greenhouse effect.
The cause of all this havoc?
In both cases, a temperature increase of about 10.8 degrees Fahrenheit [wrong - this appears to be a typo or memory error, since the science indicates it was a 10.8 degrees CENTIGRADE, or about 19 Farenheit increase - ed.], about the upper range for the average global increase today's models predict can be expected from burning fossil fuels by 2100. But these models could be the tail wagging the dog since they don't add in the effect of burps from warming gas hydrates. Worse, as the Arctic Council found, the highest temperature increases from human greenhouse gas emissions will occur in the arctic regions - an area rich in these unstable clathrates.
If we trigger this runaway release of methane, there's no turning back. No do-overs. Once it starts, it's likely to play out all the way.
Humans appear to be capable of emitting carbon dioxide in quantities comparable to the volcanic activity that started these chain reactions. According to the U.S. Geological Survey, burning fossil fuels releases more than 150 times the amount of carbon dioxide emitted by volcanoes - the equivalent of nearly 17,000 additional volcanoes the size of Hawaii's Kilauea.
And that is the time bomb the Arctic Council ignored.
How likely is it that humans will cause methane burps by burning fossil fuels? No one knows. But it is somewhere between possible and likely at this point, and it becomes more likely with each passing year that we fail to act.
So forget rising sea levels, melting ice caps, more intense storms, more floods, destruction of habitats and the extinction of polar bears. Forget warnings that global warming might turn some of the world's major agricultural areas into deserts and increase the range of tropical diseases, even though this is the stuff we're pretty sure will happen.
Instead, let's just get with the Bush administration's policy of pre-emption. We can't afford to have the first sign of a failed energy policy be the mass extinction of life on Earth. We have to act now.
John Atcheson, a geologist, has held a variety of policy positions in several federal government agencies.
| 
Fossil Fuel
