The lost East Anglian city of Dunwich is a reminder of the destruction climate change can wreak

Greyfriars Monastery, Dunwich. Image: Claude Lynch.

It’s 2019 and, if there was ever any doubt that the climate emergency wasn’t the existential issue of our times, it’s fading fast. Low-lying island chains are playing hide-and-seek with the sea, people in Iceland are writing eulogies to their favourite glaciers, the Great Barrier Reef has pulled a sickie and on top of all that this year looks to be the hottest on record. What a scorcher, they’ll say in the UK.

It’s as if we think countries like ours are somehow predisposed to not being entirely blown to bits by extreme weather; instead, we get the benefits. To us a warmer climate brings up-and-coming Surrey wine and a good excuse for a balmy stay-at-home holiday, Somerset Levels be damned.

But the UK already has proof of the damage the climate can do – a drowned city lost for good, our own Atlantis, the victim of shifting seas and a dangerous fable for any low-lying town that remains.

They called it Dunwich, Anglo-Saxon for the “town on the hill”. Located on the East Anglian coast, it was recorded in the Domesday Book as one of the largest towns in England, over 3,000 inhabitants compared to just 400 for Brighton. At its 13th century peak, its size would have rivalled that of the medieval City of London. It had almost a dozen churches, distinct quarters, bustling market squares, a town hall and even a vast monastery. But the ruined wall of the latter is the only trace that still stands of the medieval town: Dunwich has been submerged and, for the most part, forgotten.

The local museum attempts to depict what the town once was, though half of the street pattern is the result of “informed speculation”, because the original has been completely washed away by five centuries of erosion. Remarkably, a solitary gravestone remains from the graveyard of the last church to fall away into the sea. This, along with most of the remaining ruins, is predicted to collapse before 2100, removing the final titbits of evidence for the existence of a town that once rivalled London.

So what happened? The town was built on a natural bay, and grew as a hub of trade. Originally, the Dunwich River provided a protected harbour for ships coming in around the East Anglian peninsula, just as Lowestoft or Felixstowe do today.

But after a storm in 1286, the harbour began silting up and the sea encroaching. The natural spit that once sheltered the town wore away until Dunwich lay at the water’s edge in all directions: the coast was eroding by more than a metre a year. A second storm in 1328 saw 375 dwellings in three separate parishes lost in a single night. The population sank from 4500 to just over 1500 in less than 100 years – and that was before the Black Death turned things from bad to worse.


By 1587, records show that most of the street pattern remained, creating a ghost town of under 200 people. That’s roughly how many remain today, but in scattered houses further inland: almost all of the original street pattern lies beyond the sand bank. One of the greatest towns of medieval Britain effectively fell into the sea.

The chalk of the Suffolk coast is still prone to erosion, and even now there’s little incentive to protect it. While Dunwich now lies between the latter-day seaside resorts of Southwold and Aldeburgh, it never became a pied-á-terre for London’s second homeowners. Instead it was slowly abandoned and then demolished altogether, not thanks to fate or even that lovely GCSE Geography topic of “longshore drift”, but simply shifting sands.

Facsimiles of Dunwich exist all along the East Anglian coast: towns that were once of great importance, miniaturised by social and geographical trends. There’s half a dozen churches on this stretch of coast encased in the ruins of far larger ones: the skeleton of a church far larger was abandoned and replaced with a smaller one that was easier to maintain, as populations dwindled.

The onslaught of the North Sea provoked its own medieval migratory flow; it was simply no longer sustainable to keep protecting towns like Dunwich with the rudimentary sea defences of the time, so its people steadily took their leave. Today, with our modern sea defences, it’s not quite the same story. But just imagine if the storm that swept away Dunwich’s dreams came again; it’s hardly out of the question.

Salty seas, patchy records and sheer obscurity mean we didn’t build a story around the destruction of Dunwich the way we have with Pompeii or Chernobyl.  But we can use the story of Dunwich as a stand-in, until the day comes when Ely, Boston or god forbid Margate face the wrath of the cold, frigid sea.

Thousands lost their homes when the sea came to Dunwich because they weren’t ready to push it back. Either we start sympathising and supporting those across the world who face this fate today, or we renounce the sympathy of others when we eventually face the fate that our ancestors knew all too well. We need to learn from the cities we’ve lost; sometimes you have to sink a city to save one.

 
 
 
 

The IPPC report on the melting ice caps makes for terrifying reading

A Greeland iceberg, 2007. Image: Getty.

Earlier this year, the Intergovernmental Panel on Climate Change (IPCC) – the UN body responsible for communicating the science of climate breakdown – released its long-awaited Special Report on the Ocean and Cryosphere in a Changing Climate.

Based on almost 7,000 peer-reviewed research articles, the report is a cutting-edge crash course in how human-caused climate breakdown is changing our ice and oceans and what it means for humanity and the living planet. In a nutshell, the news isn’t good.

Cryosphere in decline

Most of us rarely come into contact with the cryosphere, but it is a critical part of our climate system. The term refers to the frozen parts of our planet – the great ice sheets of Greenland and Antarctica, the icebergs that break off and drift in the oceans, the glaciers on our high mountain ranges, our winter snow, the ice on lakes and the polar oceans, and the frozen ground in much of the Arctic landscape called permafrost.

The cryosphere is shrinking. Snow cover is reducing, glaciers and ice sheets are melting and permafrost is thawing. We’ve known this for most of my 25-year career, but the report highlights that melting is accelerating, with potentially disastrous consequences for humanity and marine and high mountain ecosystems.

At the moment, we’re on track to lose more than half of all the permafrost by the end of the century. Thousands of roads and buildings sit on this frozen soil – and their foundations are slowly transitioning to mud. Permafrost also stores almost twice the amount of carbon as is present in the atmosphere. While increased plant growth may be able to offset some of the release of carbon from newly thawed soils, much will be released to the atmosphere, significantly accelerating the pace of global heating.

Sea ice is declining rapidly, and an ice-free Arctic ocean will become a regular summer occurrence as things stand. Indigenous peoples who live in the Arctic are already having to change how they hunt and travel, and some coastal communities are already planning for relocation. Populations of seals, walruses, polar bears, whales and other mammals and sea birds who depend on the ice may crash if sea ice is regularly absent. And as water in its bright-white solid form is much more effective at reflecting heat from the sun, its rapid loss is also accelerating global heating.

Glaciers are also melting. If emissions continue on their current trajectory, smaller glaciers will shrink by more than 80 per cent by the end of the century. This retreat will place increasing strain on the hundreds of millions of people globally who rely on glaciers for water, agriculture, and power. Dangerous landslides, avalanches, rockfalls and floods will become increasingly normal in mountain areas.


Rising oceans, rising problems

All this melting ice means that sea levels are rising. While seas rose globally by around 15cm during the 20th century, they’re now rising more than twice as fast –- and this rate is accelerating.

Thanks to research from myself and others, we now better understand how Antarctica and Greenland’s ice sheets interact with the oceans. As a result, the latest report has upgraded its long-term estimates for how much sea level is expected to rise. Uncertainties still remain, but we’re headed for a rise of between 60 and 110cm by 2100.

Of course, sea level isn’t static. Intense rainfall and cyclones – themselves exacerbated by climate breakdown – can cause water to surge metres above the normal level. The IPCC’s report is very clear: these extreme storm surges we used to expect once per century will now be expected every year by mid-century. In addition to rapidly curbing emissions, we must invest millions to protect at-risk coastal and low-lying areas from flooding and loss of life.

Ocean ecosystems

Up to now, the ocean has taken up more than 90 per cent of the excess heat in the global climate system. Warming to date has already reduced the mixing between water layers and, as a consequence, has reduced the supply of oxygen and nutrients for marine life. By 2100 the ocean will take up five to seven times more heat than it has done in the past 50 years if we don’t change our emissions trajectory. Marine heatwaves are also projected to be more intense, last longer and occur 50 times more often. To top it off, the ocean is becoming more acidic as it continues to absorb a proportion of the carbon dioxide we emit.

Collectively, these pressures place marine life across the globe under unprecedented threat. Some species may move to new waters, but others less able to adapt will decline or even die out. This could cause major problems for communities that depend on local seafood. As it stands, coral reefs – beautiful ecosystems that support thousands of species – will be nearly totally wiped out by the end of the century.

Between the lines

While the document makes some striking statements, it is actually relatively conservative with its conclusions – perhaps because it had to be approved by the 195 nations that ratify the IPCC’s reports. Right now, I would expect that sea level rise and ice melt will occur faster than the report predicts. Ten years ago, I might have said the opposite. But the latest science is painting an increasingly grave picture for the future of our oceans and cryosphere – particularly if we carry on with “business as usual”.

The difference between 1.5°C and 2°C of heating is especially important for the icy poles, which warm much faster than the global average. At 1.5°C of warming, the probability of an ice-free September in the Arctic ocean is one in 100. But at 2°C, we’d expect to see this happening about one-third of the time. Rising sea levels, ocean warming and acidification, melting glaciers, and permafrost also will also happen faster – and with it, the risks to humanity and the living planet increase. It’s up to us and the leaders we choose to stem the rising tide of climate and ecological breakdown.

Mark Brandon, Professor of Polar Oceanography, The Open University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.