Alongside scientists, lawmakers and businessmen, officials from more than 50 ports in 35 countries started a three-day meeting in the home of Europe's largest harbour to talk about regulatory and technological ways of shrinking their contribution to global warming.

But the setting of measurable common targets appeared to be a long way off as speakers differed on such basics as the maritime transport industry's contribution to global greenhouse gas emission -- put at anything from 1.4 per cent to 4.5 per cent.

Delegates did agree, though, that the shipping sector would grow by leaps and bounds, and that alternatives had to be found in a bid to save the planet.

"The climate is changing every minute, even as we sit here," said Ogunlade Davidson, co-chairman of the United Nations' Inter-governmental Panel on Climate Change.

"Human beings have to solve it (global warming), because we created it. The marine environment has to take its own responsibility, as do all of us."

Davidson told the gathering that technical alterations, including the use of hydrodymamics in propellers, could reduce CO2 emissions by up to 30 per cent on new ships and 20 per cent on older ones.

Speed reduction and fleet maintenance also had a role to play. The potential existed to reduce the global fleet's CO2 emissions by 17.6 per cent by 2010 and 28.2 per cent by 2020, "but this will not be enough to offset the projected fleet growth," he said.

Efthimios Mitropoulos, secretary-general of the International Maritime Organisation, told delegates his organisation was working hard on setting greenhouse gas emission targets for the shipping industry.

But this could never work if developing countries were excluded from obligation, he argued, saying the developed world accounted for only 25 per cent of the world's merchant fleet.

"In my view, if reductions in CO2 emissions from ships are to benefit the environment as a whole, they must apply globally to all ships in the world fleet, regardless of their flag."