- 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".
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- 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 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.
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- 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. 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.
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- 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.
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- 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.
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- 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.
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- 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.
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- 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.
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- 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."
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- 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 crystals
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.
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- Professor Vladimir Shaidurov is an expert
in Numerical Analysis and Mathematical Modelling, and the Corresponding
member of Russian Academy of Sciences. For development of multigrid methods
he achieved the highest Russian prize in science (together with Profs Fedorenko
and Bachvalov) - the State Prize (2004). He visited University of Leicester
in April 2005.
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- Contact address: Professor Vladimir Shaidurov
Director Institute of Computational Modelling Russian Academy of Sciences
Akademgorodok Krasnoyarsk, 660036 RUSSIA
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- Email: shidurov@icm.krasn.ru
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- Shaidurov's paper "Atmospheric hypotheses
of Earth's global warming" is under consideration for publication
in the journal "Science First Hand," Published by Russian Academy
of Sciences (Editor-in-Chief, Acad. Dobretsov, Vice-President Russian Academy
of Sciences, President of Siberian Branch RAS). A preprint is available
online at http://arxiv.org/abs/physics/0510042
- which was published originally as University
of Leicester Technical Report No. MA-05-15.
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- For further information, please contact
University of Leicester:
- Alexander Gorban - 0116 223 14 33
- Jeremy Levesley - 0116 252 38 97
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- Weitere Informationen finden Sie im WWW:
- http://www.le.ac.uk
- http://arxiv.org/abs/physics/0510042
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- http://www.innovations-report.de
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