More rain is falling on Scotland. Since 1961 rainfall in winter months in northern and western Scotland has increased by an average of almost 60%. In contrast, in the summer months some parts of North West Scotland have become up to 45% drier.
Climate scientists predict that Scotland’s winters will continue to grow wetter, with less snow and fewer days of frost.
In August 2007 landslides caused by heavy rain brought hundreds of tonnes of mud into the small coastal village of Pennan in Aberdeenshire. Police and fire services had to help residents escape the severe mudslides. In 2007 Scotland experienced its wettest June since 1938.
Fifty-seven people had to be rescued in August 2004 when thousands of tonnes of debris and mud were brought down onto the A85 road near Lochearnhead by massive landslides. Emergency services, the RAF and the Royal Navy had to airlift stranded motorists to safety. In August 2004 parts of Scotland experienced more than three times the average expected rainfall.
In summer 2007 England was hit by intense rainfall and the worst floods for 60 years. In some places more than a month’s average rain fell in just 24 hours. Tens of thousands of homes were left without power and hundreds of thousands of people had no drinking water. Bottled water and water tankers were brought in to distribute safe drinking water to people hit by the floods. The Association of British Insurers predicted that the floods caused more than £2 billion worth of damage.
In November 2009 there were major floods in Cumbria, causing extensive damage. A policeman was drowned as he directed traffic from a bridge which collapsed under the force of flood water in the River Derwent.
Climate researchers have presented evidence that greenhouse gas emissions are a cause of increased rainfall. Rainfall increased by 62 mm per century between 1925 and 1999 in the region between 40 and 70 degrees North. This region includes northern Europe, Canada, and Russia. Human activity is thought to be responsible for between 50 and 85% of this increase.
'Major floods that have only happened before say, every 100 years on average, may now start to happen every 10 or 20 years. The flood season may become longer and there will be flooding in places where there has never been any before.'
Environment Agency Sustainable Development Unit
More people are seeing and experiencing the effects of flooding. The Association of British Insurers has a Geographic Information System (GIS) map that shows flood-prone housing areas throughout the UK.
More houses are being affected by more floods. More families have to cope with losing their possessions and surviving for periods without electricity and drinking water. Increasing numbers of houses are being built on flat flood plains, which means that more and more homes are at risk of flooding in the future. The Environment Agency estimates that 5 million people live in flood risk areas in England and Wales.
While it is not possible to link specific instances of intense rainfall to global warming, researchers have shown that climate change has increased the amount of rain that falls in Northern Europe and predict that warming will lead to more days of heavy rain in future.
By 2080 rainfall events will, on average, be unaffected in north-west Scotland, 25-75% more intense in east Scotland, up to 100% more intense in west Scotland and more than 150% more intense in parts of south-west Scotland.
Unlike changes in average temperature and rainfall, changes in rainfall intensity will be more dramatic in Scotland and England, increasing the likelihood of flash flooding of Scottish rivers.
Scotland and Northern Ireland Forum for Environmental Research (SNIFFER)