The ICS made the statement in response to threats of severe taxation from International Monetary Fund (IMF) managing director Christine Lagarde, who said "charges on international aviation and maritime emissions would raise about a quarter of the US$100 billion needed for climate adaptation and mitigation in developing countries."
But ICS chairman Masamichi Morooka said: "Most shipowners believe, given the severely depressed state of global shipping markets, that now is certainly not the time to impose an additional major cost on international shipping."
Continuing in his letter to Ms Lagarde, he said shipowners are willing to pay their share of costs "provided that such money is used for climate change adaptation or mitigation" and that the same charges apply to all ships regardless of flag.
He noted that two-thirds of the world`s merchant fleet is registered in nations not covered by Annex 1 of the Kyoto climate-change protocol.
"If any carbon charges were only to apply to ships registered in Kyoto Protocol Annex 1 nations, these ships would be at a major competitive disadvantage to the ships registered in non-Annex 1 nations," Mr Morooka said.
"Because of the serious market distortion that would be created, many of these ships would simply change their flag to a jurisdiction where the carbon charge did not apply."
As a carbon tax on shipping will eventually be passed on to shippers, the IMO is currently carrying out an impact assessment analysis of what a carbon tax would do to shippers in third world countries as they could suddenly find themselves at a competitive disadvantage vis-a-vis suppliers nearer to developed country markets.
The IMO hopes to present tangible proposals for a carbon tax at the next UN Conference on Climate Change scheduled to reconvene in Qatar in December 2012.