Wave climate changes in the North Atlantic and North Sea

This article presents a review of all available data describing long-term trends in the wave climate of the North Atlantic and North Sea, using both visual estimates and instrumental measurements of wave height. Long series of measurements from Seven Stones Light Vessel (1962–1986), sited off the south-west tip of England, and Ocean Weather Station Lima (1975–1988), at 57°N,20°W, are both examined for evidence of trends in mean wave height; the former data set is also examined for evidence of trends in annual maximum wave height and extreme (50-year return value) wave height. All available data show an increase in mean wave height over the whole of the North Atlantic in recent years, possibly since 1950, of about 2 per cent per year. There are insufficient data to say with confidence whether maxima or extremes have also risen.