A new theory to explain global warming was revealed at a meeting at the UK University of Leicester. The controversial theory has nothing to do with burning fossil fuels and atmospheric carbon dioxide levels but blames the warming on the Tunguska Event of 1908 that happened in a remote part of Siberia, the Science Blog reported Wednesday.
According to Vladimir Shaidurov of the Russian Academy of Sciences, the global warming of the past 100 years 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 explains that there was a slight decrease in temperature until the early twentieth century, which 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.
The Tunguska Event, sometimes known as the Tungus Meteorite is thought to have resulted from an asteroid or comet entering the earthâ€™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 â€œconsiderable stirring of the high layers of atmosphere and change its structure.â€? Such meteoric disruption was the trigger for the subsequent rise in global temperatures.
Global warming is thought to be caused by the â€œgreenhouse effectâ€?. Energy from the sun reaches the earthâ€™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 earthâ€™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. Attempts to reverse global warming, such as the Kyoto Protocol, have centered on controlling and even reducing CO2 emissions.
However, the most potent greenhouse gas is water, explains Shaidurov. Only small changes in the atmospheric levels of water, in the form of vapor and ice crystals can contribute to significant changes to the temperature of the earthâ€™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 Earthâ€™s surface more then 4 degrees Celsius.
Water vapour levels are even less within human control than CO2 levels. According to Andrew E. Dessler of the Texas A & M University, â€œHuman activities have little direct control over its atmospheric abundance, which is controlled instead by the worldwide balance between evaporation from the oceans and precipitation.â€?
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 â€™silverâ€™, 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 â€” 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.