Our coastal waters are changing fast. We need to protect them.

Storm Ciarán crossed Dorset on 2 November 2023. The National Trust recorded that it gouged away five years’ worth of beach at Studland across two high tides.

Storms now carry more rain, which climate scientists have linked to a warmer atmosphere. And every storm arrives on a higher sea, so the same wind does more damage than it would have done thirty years ago.

The deeper problem is that the beaches cannot replace themselves. Beaches survive because whatever a storm strips away is replaced by sand and shingle arriving from somewhere else, worn off cliffs along the coast or carried in from the seabed. Along much of the Dorset coast that resupply has largely stopped, so what goes is gone.

Beaches here are getting thinner and steeper, and the water just offshore is getting deeper. Deeper water lets bigger waves reach the shore, which takes more beach again.

The cliffs are moving too: 40 landslides have been recorded along the Purbeck coast since the start of 2012, 17 of them since the start of 2023.

Who is dealing with it: Dorset Council is working with residents on an adaptation plan for the stretch of coast that cannot be defended, through Future Coast North Swanage.

Sea levels around the UK have risen about 20cm since 1901. And the pace is picking up. Two thirds of that rise has happened in the last three decades alone.

Why it matters

Higher water does not just move the tideline. It means storm waves arrive at the sea wall in deeper water, so they arrive with more force.

Who is dealing with it: Dorset Council holds the Shoreline Management Plan, which sets what happens to each stretch of this coast over the next hundred years.

Our stretch of the English Channel has now had three summers running of marine heatwave conditions. The Met Office reports the Channel spent much of 2026 in marine heatwave conditions, and that UK waters were in them for more than three quarters of 2025.

In an interview, the founder of Divers Down, Pete Williams, recalled the sea here reaching about 17°C in summer in the mid 1990s. By the time he retired in 2021 it was over 18°C. In 2026, the sea swimming group is recording temperatures over 20°C.

Why it matters

Warmer water holds less oxygen. It also raises the metabolism of fish and shellfish, so they need more oxygen just when there is less available.

It also changes the ecosystem. Warm-water species are pushing east and north along this coast. Black bream, two-banded sea bream, blackspot bream and comber are all increasing and extending their range.

Who is dealing with it: Nothing, locally. Sea temperature is set globally, so the job here is measuring it rather than managing it. The nearest sea temperature record is a wave buoy in Poole Bay, about fourteen kilometres away. Wessex Water’s new buoy off Peveril Point may change that.

There is concern and anger about sewage in our seas and waterways, and this applies to Swanage Bay too.

The problem is storm overflows. When heavy rain overwhelms the sewers, Wessex Water releases diluted sewage into the sea rather than let it back up into houses. Two outlets matter here. Peveril Point is used most and sits further from the beach. Ocean Bay is used less but discharges much closer in, which is why it gets the most attention.

Putting it in perspective, Swanage has held its Blue Flag for more than twenty years. This reflects the fact that the bathing water quality is usually excellent.

What is being done

Swanage Central is a designated bathing water. The Environment Agency samples it weekly from May to September, publishes a daily pollution risk forecast, and gives the beach a classification every November, from Excellent down to Poor.

Wessex Water has committed money from 2025 to cut the use of both the Ocean Bay and Peveril Point outlets. It is also installing a wave buoy off Peveril Point, testing whether the monitoring used at Bournemouth survives in a rough, high-current spot. If it does, we should all get better information about the water we swim in.

Inland matters too. The Swanage Streams Partnership is reducing pollution reaching Swanage Bay by slowing and filtering runoff before it enters Swan Brook.

Holding the water company to account is the first action in the council’s Motion for the Ocean plan.

Who is dealing with it: The Environment Agency regulates Wessex Water and monitors every spill. Wessex Water is cutting the use of both Swanage outlets.

“There are species that we don’t see now. We don’t see the massive shoals of mackerel that you used to, or the big cod or ling, there are not as many cuttlefish as there used to be. And you also don’t see crab or lobsters of any size.”

Pete Williams, who ran Divers Down on Swanage Pier with Pat Collins for some thirty years, speaking on their retirement

He put most of it down to overfishing well beyond local boats.

The wider record backs him. Across the English Channel, cod, haddock and hake fell from 48% of the catch in 1920 to 4% by 2010. Cod and ling declined most sharply of all, and shellfish steadily replaced the fish that had gone.

Bottom trawling and dredging are the blunt end of it. A towed net takes the fish and flattens the seabed they lived on, so the habitat goes with the catch.

Who is dealing with it: Southern IFCA has closed 477.8 square kilometres of Dorset seabed to bottom-towed gear, and can close more where there is evidence.