[permaculture] So what do you really think about long term climate change...
Marimike6 at cs.com
Marimike6 at cs.com
Wed Mar 28 10:12:29 EDT 2007
It may be that methane has a short residence period in the atmosphere. But
the shock of a sudden jolt can certainly precipitate a tipping point. Also, one
has to think about the digestive process, where the methane is processed back
into the entire carbon cycle. The potential for havoc is huge, and not easily
reversed. Think Humpty Dumpty, broken.
There are two current sources of great concern. Sorry if I don't provide
sources-- I have to work today, and these topics can easily be googled.
The first is the broad scale of melting now occuring in permafrost,
especially in Siberia and Alaska. Just like burning fossil fuels, the melting of
long-frozen CO2 and methane is suddenly being added to all the man-made effluents
into the atmosphere.
The other is that marine clathrates, in the form of large beds of methane
hydrate bound by coldwater temperatures-- occuring off the Siberian coastline are
at present precariously close to the temp where it becomes dissociated--
destabilized-- sent airborne. And the surrounding waters are now warming.
As memory serves, this temp is 11 degrees C. And the surrounding Arctic
waters are approaching that mark.
If and when that occurs, we have a sudden belch into the system. And in that
event we are not talking about long term climate change any more. The climate
will have abruptly changed. The most closely studied event of this nature we
find in the geologic record is the PETM, which is easy to google. It stands for
the Paleocene-Eocene Thermal Maximum. And the consensus is that the event,
causing a wave of extinctions, was precipitated by a destabilization of a large
field of methane hydrate. Sending the planet into a sudden fever.
I hope I haven't dimmed the luster of your day. But the potential hazards of
rice paddies and cow flatulence come in a very distant second to this
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