Scotland's natural heritage is under serious threat from coastal erosion caused by climate change, it has been warned.

A fifth of Scotland's coastline is in danger, according to scientists, including the 5000-year-old Skara Brae settlement in Orkney.

The Old Course is also at risk, although natural and man-made defences have helped to protect the St Andrews Links.

A new mapping tool could help conservationists identify and protect the areas most under threat.

Speaking at the launch of Dynamic Coast in St Andrews on Friday, environment secretary Roseanna Cunningham said the problem would "probably get worse and faster".

"It's vital that local authorities, transport agencies and other planning bodies investigate how they can work together to manage coastal change before it's too late," she said.

The rate of coastal erosion in Scotland has reportedly doubled since the 1970s and scientists previously estimated that around 10,000 historic sites are in danger.

Professor Robert Furness, chairman of Scottish Natural Heritage's scientific advisory committee, said there is still "a lot of work to be done".

"About £13bn worth of property, roads and other infrastructure is already protected by natural features such as beaches and dunes, with another £5bn worth lying behind engineered defences, so nature itself protects many massively valuable assets," he said.

"However, we must also be aware that £400m worth of property, roads and infrastructure lies along coastlines that could be affected by erosion by 2050.

"Our mission now is to ensure we do all we can to protect these areas."

Dynamic Coast references more than 2000 maps and uses more than one million points of data to make predictions.

It identifies past erosion and growth as far back as the 1890s and projects forward to show potential future damage.