Re: Global Warming not man made after all?


"Just Cocky" <just@xxxxxxxxx> wrote in message
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http://www.physorg.com/news11710.html



A new theory to explain global warming was revealed at a meeting at the
University of Leicester (UK) and is being considered for publication in the
journal "Science First Hand". The controversial theory has nothing to do with
burning fossil fuels and atmospheric carbon dioxide levels.

According to Vladimir Shaidurov of the Russian Academy of Sciences, the
apparent

[There's a trigger right there. "apparent" They measure this stuff with
thermometers]

rise in average global temperature recorded by scientists over the last
hundred years or so could be due to atmospheric changes that are not connected
to human emissions of carbon dioxide from the burning of natural gas and oil.
Shaidurov explained how changes in the amount of ice crystals at high altitude
could damage the layer of thin, high altitude clouds found in the mesosphere
that reduce the amount of warming solar radiation reaching the earth's
surface.

Shaidurov has used a detailed analysis of the mean temperature change by
year for the last 140 years and explains that there was a slight decrease in
temperature until the early twentieth century. This flies in the face of
current global warming theories that blame a rise in temperature on rising
carbon dioxide emissions since the start of the industrial revolution.

[Not really, the number of people and the output of CO2 per person was
rising over this period. If the trend due to non-human issues was down it
would take a while for the new trend to appear.]

Shaidurov, however, suggests that the rise, which began between 1906 and
1909, could have had a very different cause, which he believes was the massive
Tunguska Event, which rocked a remote part of Siberia, northwest of Lake
Baikal on the 30th June 1908.

The Tunguska Event, sometimes known as the Tungus Meteorite is thought
to have resulted from an asteroid or comet entering the earth's atmosphere and
exploding. The event released as much energy as fifteen one-megaton atomic
bombs. As well as blasting an enormous amount of dust into the atmosphere,
felling 60 million trees over an area of more than 2000 square kilometres.
Shaidurov suggests that this explosion would have caused "considerable
stirring of the high layers of atmosphere and change its structure." Such
meteoric disruption was the trigger for the subsequent rise in global
temperatures.

[The impact would have been greatest at the beginning and slowly
decrease over time. This is the opposite of what is being seen. When Kraktoa
exploded it was followed by the "year with no summer".]


Global warming is thought to be caused by the "greenhouse effect".
Energy from the sun reaches the earth's surface and warms it, without the
greenhouse effect most of this energy is then lost as the heat radiates back
into space. However, the presence of so-called greenhouse gases at high
altitude absorb much of this energy and then radiate a proportion back towards
the earth's surface. Causing temperatures to rise.

Many natural gases and some of those released by conventional power
stations, vehicle and aircraft exhausts act as greenhouse gases. Carbon
dioxide, natural gas, or methane, and chlorofluorocarbons (CFCs) are all
potent greenhouse gases. Carbon dioxide and methane are found naturally in the
atmosphere, but it is the gradual rise in levels of these gases since the
industrial revolution, and in particular the beginning of the twentieth
century, that scientists have blamed for the gradual rise in recorded global
temperature. Attempts to reverse global warming, such as the Kyoto Protocol,
have centred on controlling and even reducing CO2 emissions.

However, the most potent greenhouse gas is water, explains Shaidurov and
it is this compound on which his study focuses. According to Shaidurov, only
small changes in the atmospheric levels of water, in the form of vapour and
ice crystals can contribute to significant changes to the temperature of the
earth's surface, which far outweighs the effects of carbon dioxide and other
gases released by human activities. Just a rise of 1% of water vapour could
raise the global average temperature of Earth's surface more then 4 degrees
Celsius.

[Implying, if true, that global warming has a compounding effect. As the
earth warms the existing water is more prone to evaporation and as the
glaciers melt more surface area of water is created.]

The role of water vapour in controlling our planet's temperature was
hinted at almost 150 years ago by Irish scientist John Tyndall. Tyndall, who
also provided an explanation as to why the sky is blue, explained the problem:
"The strongest radiant heat absorber, is the most important gas controlling
Earth's temperature. Without water vapour, he wrote, the Earth's surface would
be 'held fast in the iron grip of frost'." Thin clouds at high altitude allow
sunlight to reach the earth's surface, but reflect back radiated heat, acting
as an insulating greenhouse layer.

Water vapour levels are even less within our control than CO2 levels.
According to Andrew E. Dessler of the Texas A & M University writing in 'The
Science and Politics of Global Climate Change', "Human activities do not
control all greenhouse gases, however. The most powerful greenhouse gas in the
atmosphere is water vapour, he says, "Human activities have little direct
control over its atmospheric abundance, which is controlled instead by the
worldwide balance between evaporation from the oceans and precipitation."

[Again what is not noted is that - assuming the hypothesis is true - man
can play a role. The Atlantic and Gulf were unusually warm last summer. I
think few would argue that greenhouse gases played no role at all in that.
Because the Atlantic was warmer it evaporated more water - and may have given
rise to more and more intense hurricanes. More water into the air.]

As such, Shaidurov has concluded that only an enormous natural
phenomenon, such as an asteroid or comet impact or airburst, could seriously
disturb atmospheric water levels, destroying persistent so-called 'silver', or
noctilucent, clouds composed of ice ystals in the high altitude mesosphere (50
to 85km). The Tunguska Event was just such an event, and coincides with the
period of time during which global temperatures appear to have been rising the
most steadily - the twentieth century. There are many hypothetical mechanisms
of how this mesosphere catastrophe might have occurred, and future research is
needed to provide a definitive answer.

[If true I would think there would have been a sharp peak at that time.
As far as I know, that did not happen.

Bill]




Source: University of Leicester





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