KEY coastal sites which tell the story of Scotland's ancient past are in danger of being washed away, experts warned yesterday.
Archaeologists said that historic treasures could be lost forever unless action is taken now.
The most endangered sites include Viking and Iron Age remains in Shetland, Orkney and the Hebrides - where rare dry-stone brochs and Viking houses are threatened by global warming, rising sea levels, storms and erosion.
Researchers from the charity SCAPE - Scottish Coastal Archaeology and the Problem of Erosion, based at St Andrews University - expressed concern over the situation.
The charity is working with Historic Scotland to compile a list of significant historical and archaeological landmarks at risk from the waves.
Almost a third of the coastline has been surveyed already, in an audit which names several sites as "perilously close" to disappearing.
They include two prehistoric settlements at Baleshare, North Uist, which contain the remains of a circular stone house and pieces of pottery, bone and metal.
An ancient settlement at Sandwick Bay, Shetland - where a 2,000-year-old skeleton was recently uncovered - is also thought to be at risk.
The village, thought to have been inhabited between 3200BC and 2200BC, was uncovered after a huge storm and high tides in the 1850s.
When inhabited, the village would have been some distance from the sea, but as a result of relentless erosion it now stands right on the shore.
Tom Dawson, project officer at SCAPE, said climate change and an increase in stormy weather in Scotland could see more sites threatened.
He said: "It could take just one period of adverse weather to lose pieces of Scotland's history forever.
"It's been predicted that within 100 years, because of climate change, there will be much more stormy weather in Scotland and as a result, the coast will get battered even more than now.
"We need to build defences or we are just abandoning what is there. Once some of these archaeological sites have fallen in tothe sea they are lost forever.
"We don't know when they will be destroyed, but it could just take one big storm."
About 27 surveys of Scotland's coastline have been carried out since Historic Scotland began sponsoring periodic audits of the coast in 1996. But only now are experts starting to analyse the data.
Mr Dawson said: "In total, about 30 per cent of the coast has been looked at, and about 11,500 archaeological sites have been found within 100 metres of the shoreline.
"Around 3,000 are in need of further assessment.
"The problem is that as there are so many sites we have to prioritise them."