SCOTLAND’S natural coastline must be realigned and extended to combat rising sea levels which pose a threat to communities and the naval base which houses the UK’s Trident submarines, academics warn.

A study by Scottish Natural Heritage (SNH) said sea levels could rise by almost half a metre in just over five decades.

This would see coastal communities living in areas such as Greenock, Gourock, Campbeltown, Lochgilphead, Dunoon, Faslane, Inverkip, Largs, Stevenston, Irvine, Troon, Prestwick, Ayr, Girvan and  Rothesay all severely affected by the rising waters.

But according to the report, natural defences such as saltmarsh, sand dunes and beaches could be artificially extended or new new ones built to combat the rising seas.

Rivers should also be rerouted to less flood prone areas while under threat roads, bridges and building would be moved to avoid the most at risk areas.

The actions is required now as by 2080 sea levels in the Firth of Clyde could be 47cm - nearly one foot seven inches - higher than they were in 2008.

This will present “widespread challenges” in terms of managing potential effects on certain low-lying coastal areas of the Clyde.

As a result, the report warned: “This is, therefore, a widespread issue affecting the low-lying land around the Firth of Clyde.”

Infrastructure in these area could be affected, including a number of  main roads, railway lines and the rail station at Prestwick International Airport, as well as parts of the Faslane naval base, where the UK’s nuclear deterrent is based.

Mudflats and areas of saltmarsh which are currently used by birds for nesting and feeding in a protected area of the inner Clyde be at risk as well.

SNH says birds use the fragile habitats for feeding and nesting and the risk of losing it is higher because of climate change.

But others could be grown in different areas along with sand dunes, mudflats and beaches which offer a natural defence and recover quicker after being battered by the sea better than manmade objects.  

SNH chair Mike Cantlay said: “As part of our role protecting all of nature for all of Scotland, we conduct regular research into the long-term future of Scotland’s natural environment.

“We have identified more than 100 locations in the west of Scotland that may be at greater flood risk due to rising tides over the next fifty years.

“Having this advance notice allows partners to work together to address potential issues and plan ahead for ways to mitigate these risks.”

The report says three sites in the Firth of Clyde have potential for phased “managed realignment” -- Erskine South, Newshot Island, and Holy Loch.

“Managed realignment” is a technique in which river, estuary and or coastal water is deliberately allowed to extend beyond current flood defences. 

The procedure has already been followed in Scotland at Nigg in the Cromarty Firth.

It involves moving existing defences or assets landwards to create a coastal frontage more able to cope with rising sea levels. 

But some land has to be sacrificed to the inevitable when the sea levels rise.

Professor Des Thompson, of SNH, said: “There are risks, for sure, but there are opportunities to allow nature to help us cope with climate change.

“One such solution is through managed realignment of the coast. This allows natural features such as saltmarsh to act as coastal defence.

“We know that rising sea levels and changing rainfall patterns and intensities are likely to increasingly affect nature and society.

“This work forewarns us and helps us plan for these possible changes.

Clearly, sea-level rise and its potential impacts represent a widespread issue which will affect low-lying land around the Firth of Clyde.

“These types of investigations allow us to plan together and ensure the planning system supports the right development in the right place.”

Production of the report was managed by the Clyde Marine Planning Partnership which has a membership of more than 20 organisations. 

Lady Isabel Glasgow, chair of the Clyde Marine Planning Partnership, said: “Regional Marine Plans must consider potential climate change impacts and seek to adapt. In some cases natural coastal protection can provide a solution.

“It is important that land and marine planners work together on these issues to ensure that coastal and marine development is in the right place.”

The chairman of the Scottish Government-backed “Climate Ready Clyde” initiative, James Curran,  described the SNH report as “a significant step forward in understanding the impacts of sea-level rise”. 

He said: “It makes it clear that we must urgently increase efforts to reduce carbon emissions, whilst also making the challenging choices needed to adapt.”

“This research sits alongside other collaborative work with the Scottish Government, SEPA, Historic Environment Scotland, and local councils which appraises changing risks and opportunities in the light of climate change.