A group of ship owners have announced plans for a $5bn (£3.8bn) fund to design zero-emissions vessels. They says $2 (£1.50) should be levied on every tonne of ships' fuel - to support research into clean engines.
Shipping creates about 3% of the emissions that are over-heating the climate - equivalent to all of Germany's CO2.
Environmentalists welcomed the proposal but also described it as too little, too late. They say it's outrageous that international shipping pays no fuel taxes, unlike lorry owners.
Green groups argue that if ships were taxed at the same level as lorries, 70 times more cash for developing clean engines would be raised in Europe alone.
Around 250m tonnes of fuel a year are burned by ships. The International Chamber of Shipping (ICS) says that 90% of owners globally are behind the $2 levy on fuel.