Friday, July 17, 2009

Global Warming: Trapping Carbon Dioxide Or Switching To Nuclear Power Not Enough To Solve Problem

While politicians talk of investing heavily in so-called ‘clean coal’ technologies, building a new generation of fossil fuel power plants, sequestering carbon dioxide and trapping the greenhouse gas deep underground as at the recent G8 Summit at L'Aquila in Italy, two Swedish scientists argue that this will have little effect on global warming.

They argue that attempting to tackle climate change by trapping carbon dioxide or switching to nuclear power will not solve the problem of global warming, according to energy calculations published in the July issue of the International Journal of Global Warming.

Environmental engineers and renewable energy experts Bo Nordell and Bruno Gervet of the Department of Civil and Environmental Engineering at Luleå University of Technology in Sweden have calculated total energy emissions from the late 19th century to the present day, and say that using the increase in average global air temperature as a measure of global warming does not account for observed climate change. We must also take into account the total energy contained in the ground, ice sheets and oceans in order to accurately model climate change.

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.

According to Nordell and Gervet’s calculations, heat energy accumulated in the atmosphere corresponds to only 6.6% of global warming. The rest is stored in the ground (31.5%), melting ice (33.4%) and 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 missing heat is due to the greenhouse effect, natural variations in climate and/or an underestimation of net heat emissions, the researchers say.

Their calculations suggest that most measures to combat global warming - such as the widely reported remarks of former US vice president and author of the much acclaimed book 'An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do About It', Al Gore - of 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.

“Since net heat emissions accounts for most of the global warming there is no or little reason for carbon dioxide sequestration,” Nordell explains, “The increasing carbon dioxide emissions merely show how most net heat is produced.”

The “missing” heat, 26%, is due to the greenhouse effect, natural variations in climate and/or an underestimation of net heat emissions, the researchers say. These calculations are actually rather conservative, the researchers say, and the missing heat may be much less.

The total energy argument also deals a heavy blow to the case for nuclear power. Nuclear fission may not produce carbon dioxide in the same way and at the same level as burning fossil fuels, but according to Nordell it does produce heat emissions equivalent to three times the energy of the electricity it generates and so contributes to global warming significantly, Nordell adds.

However, Nordell’s focus on ‘thermal pollution’ has been subject to some intense criticism in recent years. Its detractors say that the approach contradicts decades of previous research, and even violates basic physical principles. For example, citing the Stefan-Boltzmann law that governs thermal radiation by idealised ‘black bodies’, atmospheric physicists Jörg Gumbel and Henning Rodhe claim that thermal pollution is a hundred times smaller than anthropogenic climate forcing due to greenhouse gases.

Nordell is having none of this, and insists that the net outgoing heat radiated by the planet since 1880 is greater than the geothermal heat flow, which until then had been the major heat source. This, he says, points to heat from the global use of non-renewable energy sources as being the major cause of global warming.

This argument will no doubt continue, and whoever is proved to be right, if anyone, the scholarly row is driving some very useful research on heat emissions in industrialised societies and their effect on the environment. We should expect to see revisions in the figures as models are improved and more data are collected.

(Courtesy: Francis Sedgemore)

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