(Excerpt of article from New Scientist.com 03/17/10:)
In July this year, the world's shipping lines will begin to apply pollution-cutting rules that will save tens of thousands of lives a year.
Yet these very measures - which will radically cut sulphur emissions from ships - have a downside: they will also increase global warming.
When it meets next week, the Marine Environment Protection Committee of the International Maritime Organization (IMO), the UN body that regulates world shipping, will not even be discussing setting limits on regulating the carbon emissions of shipping.
Yet it will confirm plans to slash the permitted sulphur content of fuel oil burned by most of the world's ships.
Sulphur dioxide (SO2) emissions will diminish by as much as 90 per cent, and with them the resulting haze of sulphate particles.
That's where the problem lies. By shading the planet, the haze partially masks the warming effects of greenhouse gases such as carbon dioxide also produced by the world's fleet of 100,000 ships.
Almost a billion tonnes of CO2 are emitted annually by shipping, some 3 per cent of the global total, and it was originally planned that measures to reduce these emissions would also be introduced at next week's meeting.
Those plans are now on hold. As a result, the world is set to suffer a double warming effect from shipping, says Jan Fuglestvedt of the Centre for International Climate and Environmental Research in Oslo, Norway: "one from CO2 and one from the reduction of SO2" (Environmental Science & Technology, vol 43, p 9057).
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