A new research has indicated that when the world's shipping lines will radically cut sulphur emissions from ships, they will ironically increase global warming.

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.

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.

According to a report in New Scientist, 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.

As well as providing a direct shading effect, sulphate particles also act as nuclei around which water droplets form, making skies cloudier.

Direct SO2 shading from today's shipping is estimated to cool the planet by 31 milliwatts per square metre.

Though hard to model precisely, the influence on cloud formation is likely to be three times that.

But the SO2 only stays in the air for a few days.

If it were not constantly replaced, the warming effect of the ships' CO2 emissions would quickly dominate.

This lasts for centuries.

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, one from CO2 and one from the reduction of SO2", said Jan Fuglestvedt of the Centre for International Climate and nvironmental Research in Oslo, Norway. (ANI)