Amid concern that rising sea levels threaten the future of their countries, the Pacific nations of the Marshall Islands and Solomon Islands are calling on the IMO to introduce a $100 per tonne levy on greenhouse gas emissions.
This is seen as ambitious by some and it's not clear what shape a carbon tax on the shipping industry will take.
It would also have a bigger impact on smaller shipping companies who are likely to struggle more with the costs of new, cleaner technology.
Mr Platten said: "It's complex, it needs to be a global solution, and not regional solutions, as has been mooted by various places around the world. So that's why we're calling for this discussion to start now."
Discussions could begin at an IMO meeting in June.
Professor Alan McKinnon of Germany's Kuehne Logistics University says these long-debated market-based measures are needed to cut shipping emissions.
"They would certainly give all the maritime stakeholders a much stronger financial incentive to decarbonise the sector," he said.