Waves have far more energy to strip sand from bays, undermine cliffs and threaten coastal defences than they did 30 years ago. Many resorts have already been badly damaged. Those being studied by Southampton's scientists include Christchurch in Dorset, where the local authority is having to spend millions of pounds to protect what is left. Two newly established research centres, at the universities of Cork and Galway, are investigating the effects of environmental change, including global warming and storms on Irish coasts. A survey conducted by Coastwatch Europe last year found that wave erosion is still the main threat to Ireland's coastline.
Scientists link the bigger waves to changes in the Atlantic weather systems.
In the northernmost Atlantic, weather is dominated by a zone of low pressure near Iceland which is responsible for much of Europe's bad weather. The tropics are dominated by the Azores, with a zone of high pressure and better weather. Challenor and his Southampton colleagues believe the pressure difference between the two zones has increased, causing the winds between the two areas to become stronger and more persistent. Waves are generated by these winds pushing on sea water. Alan Davies of Bangor University, an expert on the interaction of waves, currents and tides in coastal waters, said even small increases in wave height could devastate coastal defences.