LONDON-Coastal communities face “serious questions” about their long-term safety from rising seas, a senior Environment Agency official has warned.

People have become used to a ‘myth of protection’, according to John Curtin, head of floods and coastal management.

“We are in a cycle of thinking we can protect everywhere always”, he told BBC News. His warning follows research suggesting polar melting is accelerating and raising the height of the oceans. And a major UN study last year said extremes of coastal flooding are set to become far more frequent.

What’s this warning all about?

Mr Curtin is taking a long view about how climate change is set to increase the level of the sea and alter the coastline.

As a leading specialist in flood defence in England, he wants to trigger a public debate about how to respond.

He believes that since the 1960s, when huge concrete embankments were built along many stretches of shore, several generations have grown up taking coastal protection for granted. Now, he says, there’s an urgent need for ‘difficult conversations’ about how to respond to the prospect of much higher seas. In some locations that will mean bigger, stronger defences but in others the conclusion may be that it’s better for people to move inland.

“If the seas rise by another metre, they get more stormy, there are some places that are really vulnerable.

“We might need to look at where people live eventually.”

What does he have in mind?

Mr Curtin was speaking as he guided me around a new flood scheme in Boston in Lincolnshire, a town repeatedly hit by North Sea storm surges in recent decades. Each surge was higher than the last - in 1953, in 1978 and in 2013 - and every time the response was to improve coastal defences by raising embankments. The most recent flood hit 500 homes and 300 businesses and caused £1m worth of damage to Boston’s famous St Botolph’s church, known locally as the Stump. It led to a massive project to defend the town with a tidal barrier, now under construction at a cost of more than £100m. A smaller version of the Thames Barrier which protects London, the scheme involves a steel wall that can be raised into position to hold back the sea if a storm surge is forecast.

Doesn’t that fix the problem?

Yes, for several decades at least. Mr Curtin describes the Boston barrier as “brilliant” - and one of many new schemes around the country.

But he is concerned about the long-term future even for somewhere that’s well-defended.

The new barrier is designed with sea level rise in mind - about 1.5m higher than the last 2013 surge - but there is a risk that climate change will prove more rapid than expected.

“What if sea level rise happens faster? What do we do beyond the next Boston scheme…” This isn’t just a question of cost, although the sums involved are huge. It’s also a practical issue, of whether gigantic engineering is the best answer.