Atmospheric pollution
The shipping industry is a small contributor to the total volume of atmospheric emissions compared to road vehicles and air transport (see graphic below) as well as public utilities such as power stations, and atmospheric pollution from ships has reduced in the last decade. There have been significant improvements in engine efficiency and hull design, and the use of ships with larger cargo carrying capacities have led to a reduction in emissions and an increase in fuel efficiency.
However, there is worldwide concern about atmospheric pollution and global warming and the shipping industry has been playing its part in high level discussions at the International Maritime Organization (IMO) on reducing ships' emissions.
Comparison of CO2 emissions by different transport modes
Source: NTM (Swedish Network for Transport and the Environment)
In terms of CO2 emissions per tonne of cargo transported one mile, shipping is recognised as the most efficient form of commercial transport. However, the enormous scale of the industry means that it is nevertheless a significant contributor to the world's total greenhouse gas emissions (around 3% of total global CO2 emissions).
The industry is therefore closely involved in global discussions on ships' CO2 emissions now being firmly led by IMO, and has worked to develop proposals for maritime transport in advance of the UNFCCC conference on climate change in Copenhagen in December, which will develop further the post Kyoto regime. More information about what the shipping industry and IMO are doing to deliver a significant reduction in shipping's CO2 emissions can be found at www.shippingandco2.org.
Comparative exhaust gas emissions
Source: NTM (Swedish Network for Transport and the Environment)
Another major task for the future is to improve the quality of fuel oil supplied to ships by the oil companies, the sulphur content of which is relatively high. In October 2008, IMO adopted a number of important amendments to Annex VI of the IMO MARPOL Convention (which regulates air emissions), which introduced more stringent controls on NOx and undertook to gradually reduce the global limit for SOx emissions from 4.5% to 0.5% sulphur content in fuel by 2020 (subject to a feasibility review).
Meanwhile, improvements in hull design are expected to lead to further reductions in fuel oil consumption with consequent reductions in air pollution. The latest marine engines give a 30%-40% reduction in discharges of nitrogen oxide, with reductions of 60% likely in the future. The industry has also been exploring other possible solutions, such as the use of alternative fuels, although for the foreseeable future fossil fuels will probably continue to be the predominant source of power for the majority of the industry.