Sunday, August 30, 2009
Researchers find out a different perspective of Global Warming
Most of us tend to think of global warming in terms of the greenhouse effect produced by CO2 emissions. While it may be partly true that CO2 emissions interfere with the radiation of the heat from sunlight back into space and thus warm up the atmosphere, the main culprit could be the amount of energy we produce and use; and the heat energy that is let out into the atmosphere in this process. Anyone familiar with thermal power plants would know that the efficiencies (ratio of electrical energy output to fuel energy input) are on average around 35%, with the cooling water taking away the bulk of the heat when steam is condensed into water. Even the useful energy that is produced is ultimately lost in space in the form of heat produced in various processes in which this energy is used.
Researchers Bo Nordell and Bruno Gervet of the Department of Civil and Environmental Engineering at Lulea University of Technology in Sweden have calculated the total energy emissions from the start of the industrial revolution in the 1880s to the modern day. They have worked out that using the increase in average global air temperature as a measure of global warming is an inadequate measure of climate change. They suggest that scientists must also take into account the total energy of the ground, ice masses and the seas if they are to model climate change accurately.
The researchers have calculated that the heat energy accumulated in the atmosphere corresponds to a mere 6.6% of global warming, while the remaining heat is stored in the ground (31.5%), melting ice (33.4%) and in sea water (28.5%). They point out that net heat emissions between the industrial revolution circa 1880 and the modern era at 2000 correspond to almost three quarters of the accumulated heat, i.e., global warming, during that period.
The researchers also point out a flaw in the nuclear energy argument. Although nuclear power does not produce carbon dioxide emissions in the same way as burning fossil fuels, it does produce heat emissions equivalent to three times the energy of the electricity it generates (using the thermal cycle of steam turbine) and so contributes to global warming significantly.
Their calculations suggest that most measures to combat global warming, such as reducing our reliance on burning fossil fuels and switching to renewables like wind power and solar energy, will ultimately help in preventing catastrophic climate change in the long term. But the same calculations also show that trapping carbon dioxide, so-called carbon dioxide sequestration, and storing it deep underground or on the sea floor will have very little effect on global warming.
Posted by Arunava ---- Saviour of Forests at 8/30/2009 11:43:00 PM