Author(s)

S.G. Tsyro & E. Berge

Abstract

The contribution of sulphur (SO₂) and nitrogen oxides (NO_x) emissions from international shipping in the North Sea and the north-eastern (NE) Atlantic Ocean to acidifying deposition across Europe is evaluated for 1990, 1995 and 2010 with the EMEP (European Monitoring and Evaluation Programme) two-dimensional trajectory model. A new ships emission data set for the North Sea and the NE Atlantic Ocean is implemented based on information from the Lloyd's Register of Shipping. The new emissions of SO₂ and NO_x are a factor of 2.2-2.8 larger then the earlier estimates used. Therefore, the presented calculations give considerably higher ships' contribution to acidification in Europe. Ship emissions from the North Sea and the NE Atlantic Ocean in 1990 exceeded 100-150 mg m^-2 a^-1 and accounted for more than 10-15% of the total acidifying deposition in many coastal areas. That is comparable with the contributions of large industrial countries.

The considerable decrease of the total European emissions of SO₂ and NO_x by 26% and 15% respectively between 1990 and 1995 was mainly due to the reduction of land-based emissions, whilst ship emissions are thought to remain comparatively stable. Consequently, a relative increase of importance of international shipping to acidification is registered. Our estimates also suggest that the importance of ship emissions in the North Sea and the NE Atlantic Ocean will increase in 2010 providing that European countries have reduced their national emissions according to the current reduction plans and no abatement measures with respect to international shipping are taken.

Keywords