Nearly 200,000 homes are at risk of being abandoned by the 2050s - and East Devon is on the list of affected areas, according to new research.

The district - which includes Sidmouth, Exmouth, Lyme Regis and Seaton - features in the top 20 places which would be hardest hit should water levels rise by around 35cm in the next 28 years, as forecasts warn.

According to new research published in the peer-reviewed journal Oceans and Coastal Management, sea level rises caused by climate change are putting nearly 200,000 English properties at risk of being abandoned by the 2050s.

The study was led by Paul Sayers, an expert on flood and coastal risks who works with the Tyndall Centre at University of East Anglia and advises the Climate Change Committee (CCC).

It concluded mean sea levels around England will be around 35cm higher by 2050 than their historical level and will continue to rise as increasing global temperatures, due to greenhouse gas emissions, melts glaciers and ice caps and causes ocean waters to expand as they warm.

In addition, foreshores are at risk of being eroded, which can further deepen the water at the coast leading to larger waves reaching the shore.

The combination of sea-level rise and larger waves will greatly increase the number of properties at risk of flooding.

Investment in improved sea walls and other defences will protect many of the properties at risk, but this will not be affordable or possible everywhere.

For the first time, the new study calculates how many English properties will be threatened with coastal flooding but where the costs of improving defences may be too high or technically impossible for the government to continue to protect communities, given current funding regimes.

The researchers found that, by the 2050s, 120,000-160,000 properties along the English coast are at risk of relocation due to sea level rise, in addition to 30-35,000 properties that had already been identified as at risk from sea level rise.

This means the number of properties at risk is five times higher than suggested within current shoreline planning documents, and many communities that face an uncertain future haven’t yet been identified.

In 2018, the CCC identified 100,000 properties that would be at risk from sliding into the sea due to coastal erosion - meaning around 300,000 properties are at risk from sea level rise and coastal erosion.

This analysis found that around 30% of local authority assessments, known as Shoreline Management Plans, which recommend ‘Hold-the-Line’ in the longer term - implying that sea defences will be built and maintained along the shoreline - may be unrealistic as sea levels rise due to cost or feasibility constraints, covering 1,700km of the English coast.

When will homes start to be lost?

In March 2020, 41% of mortgages had terms longer than 25 years and the median first-time buyer mortgage now lasts for 30 years.

Many people may be buying houses or paying off mortgages on properties which will not be habitable or will be within a few years of being abandoned by the end of the mortgage term.

Most people who are likely to be in this situation will be unaware of it and there is currently no government scheme to help them.

Which local authorities have the most properties at risk?

A total of 20 local authorities have 2,000 or more (some with tens of thousands) at risk of being lost to sea level rise including (ranked in order from most numbers of properties to fewest):
1. North Somerset
2. Sedgemoor
3. Eastbourne
4. Wyre
5. North East Lincolnshire
6. Warrington
7. Swale
8. Dover
9. Portsmouth
10. Tendring
11. Ipswich
12. Gloucester
13. Bristol City
14. Maldon
15. Adur
16. Cornwall
17. East Devon
18. East Lindsey
19. East Suffolk
20. West Lancashire

Sidmouth Herald: The map of potentially affected areas in the UKThe map of potentially affected areas in the UK (Image: Global Strategic Communications Council (GSCC))

Decisions on precisely which, and how many, of these properties and communities will have to move will depend on government policy, the research concluded.

Since sea level rise responds relatively slowly to changes in global temperatures these risks in the 2050s are now almost inevitable, even if emissions are now cut rapidly, it said.

But faster emission cuts will greatly reduce the amount of sea level rise later this century and beyond.

Lead author Mr Sayers said: "Significant sea level rise is now inevitable. For many of our larger cities at the coast protection will continue to be provided, but for some coastal communities this may not be possible.

"We need a serious national debate about the scale of the threat to these communities and what represents a fair and sustainable response, including how to help people to relocate."

How can we transition to stop this?

The study argues that England faces “a transformational challenge” but that there is a “lack of clarity as to how this transition will be made, particularly when it would impact communities”.

A new round of updates to local authority plans, which is happening now, is an opportunity to promote a more open discourse including where it is necessary to discuss relocation, according to the study.
It warns that postponing hard choices has consequences including “further (inappropriate) development [on flood plains]” or unfairly propagating “the belief that protection will continue in the long term”.

The study assessed a number of factors to determine the likely pressure for relocation including the type of settlement and landscape, the existing local authority plan, the economic case for continuing to protect properties, and shoreline vulnerability.

Large towns and cities are assumed to warrant Hold-the-Line protection while small communities are more vulnerable.

The economic case was assessed on a cost-benefit analysis using a lower cost-benefit ratio than is usually used to calculate whether projects should attract central government support, meaning the study potentially underestimates the number of properties at risk.

The combination of sea level rise and seabed erosion means that it will not be technically feasible to defend some areas, regardless of the question of cost, the report adds.

The types of areas most at risk from sea level rise

They include:

Single communities: For example, Fairbourne in Wales, which is already due to be abandoned to sea level rise.

These communities contain a large number of properties (Fairbourne has a population of 700 people) but the complexity of the shoreline and floodplain means that the cost of maintaining defences is so large that it can’t be justified.

Communities containing dispersed clusters of properties on a long floodplain: For example, the Somerset Levels, East coast and North West.

A narrow floodplain, with properties on, constrained between the shoreline and raising ground, e.g. Dawlish (Dawlish is being protected but other places like this may not be so lucky) - often roads and railways run along these areas

Small quay and coastal harbours communities: For example, quays across Cornwall - low lying properties squeezed between a rising ground and harbour quay walls

Professor Jim Hall, Professor of Climate and Environmental Risks and former Director of the Environmental Change Institute at the University of Oxford, said: "We need to have honest conversations with coastal communities that it will simply not be possible to protect every house and business from sea level rise.

"These changes are coming sooner than we might think and we need to plan now for how we can adjust, including a nationwide strategic approach to deciding how to manage the coast sustainably in the future."