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Topic: RE: virus: Siberia's rapid thaw causes alarm (Read 790 times) |
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Blunderov
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"We think in generalities, we live in details"
  
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RE: virus: Siberia's rapid thaw causes alarm
« on: 2005-08-12 18:30:40 » |
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[Blunderov] Chaos begins to kick in too? It's a gloomy prospect but what
else will turn up that we didn't know we didn't know?
Glumly.
http://news.bbc.co.uk/2/hi/science/nature/4141348.stm
Siberia's rapid thaw causes alarm
The whole western Siberian sub-Arctic region has started to thaw
The world's largest frozen peat bog is melting, which could speed the rate
of global warming, New Scientist reports.
The huge expanse of western Siberia is thawing for the first time since its
formation, 11,000 years ago.
The area, which is the size of France and Germany combined, could release
billions of tonnes of greenhouse gases into the atmosphere.
This could potentially act as a tipping point, causing global warming to
snowball, scientists fear.
The situation is an "ecological landslide that is probably irreversible and
is undoubtedly connected to climatic warming," researcher Sergei Kirpotin,
of Tomsk State University, Russia, told New Scientist magazine.
The whole western Siberian sub-Arctic region has started to thaw, he added,
and this "has all happened in the last three or four years".
Warming fast
Western Siberia has warmed faster than almost anywhere on the planet, with
average temperatures increasing by about 3C in the last 40 years.
The warming is believed to be due to a combination of man-made climate
change, a cyclical atmospheric phenomenon known as the Arctic oscillation
and feedbacks caused by melting ice.
When you start messing around with these natural systems, you can end up
in situations where it's unstoppable
David Viner, climate scientist
The 11,000-year-old bogs contain billions of tonnes of methane, most of
which has been trapped in permafrost and deeper ice-like structures called
clathrates.
But if the bogs melt, there is a big risk their hefty methane load could be
dumped into the atmosphere, accelerating global warming.
Scientists have reacted with alarm at the finding, warning that future
global temperature predictions may have to be revised.
"When you start messing around with these natural systems, you can end up in
situations where it's unstoppable," David Viner, of the University of East
Anglia, UK, told the Guardian newspaper. "There are no brakes you can apply.
"This is a big deal because you can't put the permafrost back once it's
gone. The causal effect is human activity and it will ramp up temperatures
even more than our emissions are doing."
The intergovernmental panel on climate change speculated in 2001 that global
temperatures would rise between 1.4C and 5.8C between 1990 and 2100.
However these estimates only considered global warming sparked by known
greenhouse gas emissions.
"These positive feedbacks with landmasses weren't known about then," Dr
Viner said. "They had no idea how much they would add to global warming."
-----Original Message-----
From: owner-virus@lucifer.com [mailto:owner-virus@lucifer.com] On Behalf Of
Jonathan Davis
Sent: 09 August 2005 16:33
To: virus@lucifer.com
Subject: RE: virus: The Democrofascists.
Interesting thread this fellows. Very interesting comments from you K. Just
wanted to toss in my full agreement with you.
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Kharin
Sent: 08 August 2005 20:04
To: virus@lucifer.com
Subject: Re: virus: The Democrofascists.
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the.bricoleur
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making sense of change
 
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RE: virus: Siberia's rapid thaw causes alarm
« Reply #1 on: 2005-08-18 05:38:28 » |
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The response of permafrost to warming is quite slow, and before a complete thaw occurs there is a stage of relic(t) permafrost. In central Manitoba the town of Thompson has building lots you can develop only if you insulate your house from melting the underlying permafrost; or you melt the permafrost before you build. This is relic permafrost that once thawed does not re-freeze. There are large areas of relic permafrost at the edges of permanent permafrost, defined by the fact it refreezes if thawed. Relic permafrost is one of the issues that makes deep soil temperature profiles troubling. The existence of this permafrost in an area that has been out from under the ice for approximately 6000 years speaks to the insulating properties of soil and how slowly warmer air temperatures lead to higher soil temperatures. It is interesting to note that in the permafrost region the soil thaws in the summer in the active layer while in relic and non-permafrost soil the surface layer freezes in the winter. Of course, it is the water in the soil that freezes not the soil itself and this indicates that precipitation patterns are also a factor. There is also interesting work on the correlation between the permafrost line, plant growth and insect populations.
This is an important point. It is the water in the soil that freezes and the ice of the permafrost that melts. This brings into play the need for latent energy to melt the permafrost and the permafrost does not 'warm' until the water is melted.
The question is posed, then, where is all the energy to melt the permafrost coming from? The high latitude regions are regions of net radiation loss to space - through the year there is more LW radiation to space than the solar radiation absorbed over summer. Greenhouse gases are not a source of energy; they only act to reduce the net LW radiation loss at the surface.
The historical temperature records indicate that the high northern latitudes were as warm during the 1930s as they are now, with a colder interval between.
1) Did the solar irradiance go through cyclic intensity that would produce such a temperature variation through direct changes in surface heating?
2) Did the atmospheric greenhouse gas concentrations go through a cycle that would explain more backradiation in the 1930s and 1990s but reduced back radiation in the 1950s, 1960s and 1970s?
3) Was it like IPCC models suggest, with more intense solar radiation in the 1930s and more anthropogenic greenhouse gas concentrations in the 1990s?
4) Do we need to take account of the internal variability within the climate system, especially that the poleward transport of energy necessary to achieve near global energy balance of the climate system varies on multi-decadal timescales and the poleward transport was more intense in the 1930s and 1990s (net warming of high latitudes) and less intense over intervening decades (net cooling of high latitudes)/
The first three explanations require the poleward transport of energy, especially by the atmosphere, to be constant and not affected by the equator to pole temperature gradient - limited internal variability of the climate system. Given that the atmosphere and oceans are interacting fluids in motion I suggest that this notion is highly unlikely. Trenberth and Caron, in their 2001 J of Climate article, have assessed the peak annual mean poleward transport of energy by the atmosphere as about 5x10^15 watts. A back of the envelope calculation indicates that a one percent increase in the transport would provide enough additional energy to the polar regions to melt the Arctic sea ice within ten years. Relatively small variations of poleward energy transport provide large variations in the amount of energy imported to polar regions. Radiation emission of energy to space is regulated by the prevailing temperature and, as a consequence, the additional energy imported will be taken up as latent energy to melt ice or surface warming where there is no ice.
Internal variability of the climate system is a powerful tool for multi-decadal and longer period climate variability. Internal variability is a phenomenon that IPCC does not recognise because computer models are heavily damped in order to preserve computational stability and so the models have only limited internal variability. "The warming over the past 100 years is very unlikely to be due to internal variability alone, as estimated by current models" (IPCC TAR SPM p10). It is almost as if there is a belief that 'if it is not in our models then it does not exist' without recognising the nature of the atmospheric and ocean fluids.
If any melting of the permafrost is to be attributed to increased concentration of anthropogenic greenhouse gases then it is necessary to demonstrate that the reduction in net surface LW radiation loss will provide the necessary accumulation of latent energy over the timeframe of consideration. The work of Trenberth and Stepaniak (J of Climate, 2003 vol 16 p 3706) supports the view that generally warmer tropical SST (at least during El Nino) will enhance the poleward transport of energy by the atmospheric circulation. There have been warmer tropical SST since the 'climate shift' of 1976. MacPhaden and Zhang suggest that the warmer tropical SST since 1976 have been the result of reduced upwelling of cold subsurface water in the surface layer.
An increase in the amplitude of the Rossby Waves will result in a greater poleward transfer of energy, while colder air with less energy is transported toward the equator. Of course, those waves extending toward the pole move over surfaces that manifest their passage by creating a deeper and more prolonged seasonal occurrence of the Active Layer: melting of the permafrost? Those moving south create transitory manifestations such as early frost or early thaw but not prolonged evidence. Look at the increased amplitude of these waves in the late 1980s, 1990s and up until last year. An increase in the depth and seasonal length of the Active Layer is not permanent permafrost melting.
Science and logic support internal variability of the climate system, and variations in poleward transport of energy, as being a significant contributor to variability of high latitude surface temperature and polar ice mass.
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