Ticking Time Bomb
By John Atcheson
12-27-4
"We have built a greenhouse, a human greenhouse, where
once there bloomed a sweet and wild garden."
-- Bill McKibben
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, 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.
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.
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