Abstract
International shipping and its contribution to climate change: More than 80% of the global trade is conducted via the oceans and seas. Presently, shipping is one of the fastest growing emission sectors. Key compounds emitted are the greenhouse gas (GHG) carbon dioxide, nitrogen oxides, sulphur dioxide, carbon monoxide, black carbon, and particulate matter. International shipping is estimated to
have contributed about 2.7% to the global emissions of carbon dioxide in 2007. Emissions of nitrogen oxides lead to the formation of the GHG ozone and reduce the GHG methane. Ship emissions of sulphur dioxide cause cooling by the formation of sulphate aerosols and effects on marine boundary layer clouds.
Currently, the global mean radiative forcing from shipping is negative and implies cooling. In the longer term, emissions from shipping will result in a warming response as the long atmospheric life time of carbon dioxide will overwhelm any shorter-term cooling effects.
