A large fraction of ship emissions occurs within 400 km of coastlines, causing air quality problems in coastal areas and harbours with heavy traffic. Pollution from marine shipping causes numerous premature cardiopulmonary and lung cancer deaths around the world each year, according to a report led by scientists of the University of Delaware and Rochester Institute of Technology (USA) published recently in Environmental Science and Technology, with impacts concentrated in coastal regions along major trade routes. CO2 and sulphur dioxide (SO2) from ships also contribute to acidification of the ocean, which poses a potential threat to marine biota. In addition, CO2 remains in the atmosphere for a long period of time and will therefore continue to have a warming effect long after its emission. In contrast, sulphate has an atmospheric residence time of typically only a few days, and the climate response from sulphate is of the order decades while that of CO2 is on the order of centuries. Thus, shipping with sulphur rich fuel should not be considered as an option to face global warming caused by continuous emissions of greenhouse gases.
We conclude that while the control of NOx, SO2 and particle emissions from ships will have beneficial impacts on air quality and acidification, CO2 reductions from all sources, including ships and other freight modes, are urgently required to reduce global warming.
The research was supported by the German Helmholtz-Gemeinschaft Deutscher Forschungszentren and the German Aerospace Center (DLR) within the Young Investigators Group SeaKLIM and by the Oak Foundation.
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Corbett, J., J. Winebrake, E. Green, P. Kasibhatla, V. Eyring, and A. Lauer: Mortality from Ship Emissions: A Global Assessment, Environ. Sci. Technol., in press, 2007.