The global shipping industry is delivering real CO2 reductions, despite an increase in maritime trade, according to a study by the International Chamber of Shipping (ICS).
The progress has been highlighted ahead of the United Nations Climate Change Conference in December this year.
According to ICS, the current CO2 emissions from international shipping represents 2.2% of the total CO2 emissions across the world, compared to 2.8% in 2007.
ICS secretary general Peter Hinchliffe said: "These are genuine reductions through fuel efficiency, without the need for complex virtual measures such as carbon offsets.
"With bigger ships, better engines and smarter speed management, the industry is confident of a 50% CO2 reduction by 2050 when the entire world fleet will comprise super fuel-efficient ships, many using clean fuels such as LNG."
The UN International Maritime Organization (IMO) has already mandated all ships built from 2025, including those in developing nations, to be 30% more efficient than ships built in the 2000s.
The global shipping industry is already delivering carbon neutral growth having reduced total CO2 emissions by more than 10% since 2007, ICS noted.
Hinchliffe added: "The entire world fleet is about 20% more efficient than in 2005.
"With the support of the shipping industry, IMO has already achieved a great deal and is the only forum that can deliver further significant CO2 reductions from international shipping."
In April this year, the European Parliament approved the draft EU rules that demand ship owners using EU ports to monitor and report CO2 emissions each year.
The new rules, which will come into effect from 2018 for ships of more than 5,000gt, is aimed at an EU-wide system for monitoring, reporting and verification (MRV) of greenhouse gas emissions from shipping.