The carbon tax, the most ambitious measure on the table, would make it more expensive for shipping companies to emit greenhouse gases, encouraging them to curtail emissions.
But some member states, including China and Brazil, are proposing other measures, arguing that the carbon levy would increase the cost of goods and contribute to food insecurity.
The IMO expects to come to an initial agreement by Friday next week on which mechanism to adopt to help reach carbon neutrality in shipping by 2050.
The stakes are high as shipping accounts for nearly three percent of global greenhouse gas emissions, according to the IMO.
“(It is) difficult to say what will happen next week,” Fanny Pointet, sustainable shipping manager at European advocacy group, Transport and Environment, told AFP.
The United States has been notably quiet about the issue, having not commented since President Donald Trump returned to the White House.
The Pacific and Caribbean island states are leading the group pushing for a carbon tax, with support from other countries including the UK.
They argue that funds raised from a levy could be redistributed to nations most vulnerable to climate change to help adapt and mitigate its effects.
“Climate change is a terrifying lived reality for my country,” said Albon Ishoda, the Marshall Islands’ representative to the IMO.
