The shipping industry says there needs to be more research into new technology before emissions targets set by the International Maritime Organization can be reached.
Pacific Island nations were central to pushing a deal that was struck last week by more than 170 countries at the International Maritime Organization, or IMO, to halve greenhouse gas emissions by 2050 compared to 2008 levels.
World Shipping Council CEO John Butler said that while the industry supports efforts to cut emissions, there is currently no technology that will allow them to reach this target.
"In order to get to these goals it will be necessary to stand up a very substantial research and development exercise or effort to figure out which technologies are most promising and the pursue those technologies to the point where they can be safely and commercially deployed on a vessel."
John Butler says his organisation is calling for the IMO to fund, direct and monitor a research programme into better fuel efficiency in the shipping industry.