Global warming could lead to an increase in the storminess that disrupts the ferry services that are critical to Scottish island communities, says Tyndall research that has assessed changes in wave height with fluctuations in winter weather patterns.
The North Atlantic Oscillation (NAO) is one of the oldest recognised weather patterns and it determines whether

winters in Northern Europe will be wet and warm, or cold and dry. It's influence on winter weather has increased in recent decades, although it is not clear whether this is specifically linked with global warming.
Tyndall researcher John Coll at the Environmental Research Institute of the University of the Highlands and Islands said "the lifeline ferry services to the islands are already heavily subsidised - one possibility might be the need for bigger and more expensive boats".
The findings result from the application of a new methodology for local scenarios of climate change, sea level and wave heights, analysed along with data on weather-related disruptions of ferry crossings. The methodology has been developed by Mikis Tsimplis and David Woolf from Southampton Oceanography Centre as a component part of a large-scale Tyndall assessment of the vulnerability of the UK coast to climate change.
"Moving away from regional case-studies, the overall influence of the NAO's impact on sea levels around the UK coast is likely to be small. Nevertheless, wave heights at the North East atlantic will continue to increase further," says Mikis. His recently completed research shows that sea level, wave heights and extreme surges along the north European coast are positively correlated with the winter behaviour of the NAO, and southern Europe's coastal weather is negatively correlated with the NAO. The UK is located between these positive and negative influences and so the overall impact is smaller than for other European coastlines.

for further information:
John.Coll@thurso.uhi.ac.uk