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SHIPS, SULPHUR AND CLIMATE

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HELSINKI, Sep 7 2010 (IPS) - The year 2010 has, like previous years, produced an impressive array of climate-related news, much probably related to global warming. Numerous global and national heat records have been broken: 37.2 degrees Celsius in Finland, 35 degrees in Yakutia, and 54 degrees in Pakistan. Forest and peat fires have done enormous damage in Russia, and Pakistan has been swept by floods and mudslides. A huge ice floe broke free from the Petermann Glacier in northwest Greenland, and the extent of marine ice in the Arctic Ocean is the second smallest ever recorded, in spite of a cool and cloudy July. Such news becomes even more worrying when viewed in a slightly longer perspective.

In 1994 it was estimated that there was approximately 25,000 cubic kilometres of floating pack ice at the Arctic Ocean. Since then the amount has been reduced by at least 80 percent. Open water has a very low reflectivity. Whereas ice and snow typically reflect between 70 and 90 percent of solar radiation straight back to space, watery surfaces only reflect between 4 and 10 percent. Thus the loss of sea ice could thus greatly accelerate the warming of the polar areas.

In addition, there are enormous natural reserves of organic carbon and methane in the Arctic. The terrestrial permafrost areas alone have been estimated to contain 1.5 trillion tonnes of organic carbon. Much of this could be released into the atmosphere in the form of methane, a very potent greenhouse gas, if the permafrost melts.

About one half of the bottom of the Arctic Ocean is covered by submarine permafrost; there are also methane hydrate fields, mysterious underwater mixtures of ordinary ice and methane gas trapped inside and under the ice. The melting of the submarine permafrost and the hydrate fields could, in theory, release so much methane and carbon dioxide that our own greenhouse gas emissions would seem insignificant in comparison.

There are now signs that something like this is already starting to happen. In August 2009 a team of the University of Southampton discovered around the Arctic archipelago known as Spitzbergen 250 sites at which submarine hydrate fields had started to melt and release methane.

In the present situation, it is of utmost importance to halt the melting before things really get out of hand. However, while there has been little advance in the negotiations to reduce our globe-warming greenhouse gas emissions, the efforts to cut our cooling emissions have proceeded with lightning speed.

The International Maritime Organisation (IMO) decided in October 2008 that the maximum allowable sulphur content in the fuel used by ocean-going ships should be reduced to 0.5 percent by 2020 from the present average of 2.7 percent.

According to the best estimate currently available, ship sulphur emissions now cool the planet with an efficiency of 0.58 watts per square metre. The tiny sulphur droplets assist the formation of low-lying clouds, which have a cooling impact on our planet. In addition, sulphur droplets make clouds whiter and more reflective and increase their life-span. The effect is especially important over the oceans, where there is often a scarcity of tiny particles that can act as condensation nuclei for clouds.

According to a widely-quoted assessment, enforcement of the IMO treaty would reduce the ships’ cooling impact by 0.31 watts per square metre. This may not sound like much but according to measurements conducted by NASA using satellites and other instruments, our planetary heat imbalance –also known as global warming– currently amounts to 0.85 watts per square metre.

In other words the enforcement of the IMO treaty might increase global warming by 36 percent, from 0.85 to 1.16 watts per square metre. This could be dangerous, especially because the impact would not be evenly distributed. It would concentrate over the oceans, especially at the North Atlantic and at the Arctic Ocean.

Sulphur is harmful to human health, so it does make sense to cut maritime emissions close to densely populated areas, like the Baltic and the Mediterranean. But sulphur emitted in the middle of the ocean can hardly be an important health issue.

Is this really the time to invest up to USD 200 billion per year to cut ocean-going ships’ sulphur emissions? The IMO treaty is well-meaning, but it might push us over the edge. (END/COPYRIGHT IPS)

(*) Risto Isomaki is an environmental activist and awarded Finnish writer whose novels have been translated into several languages

 
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