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I’ve just walked more than 180 miles across land that will, almost certainly, soon be lost to the oceans. How soon is soon? The terrifying answer is we simply don’t know.
On the Norfolk coast, I walked for four days past low-lying villages and farmland protected from high tides and storm waters only by sand dunes, shingle ridges, and raised embankments. In the east of the county, I walked three further days along Europe’s most rapidly eroding coastline. There, in front of villages like Happisburgh and Hemsby, the beaches were strewn with fragments of piping, cables, roads, and homes that had fallen down the cliff.
But sea level rise isn’t just a coastal problem, for large parts of inland England are already at or below sea level and are highly vulnerable too – through the Cambridgeshire Fens and the Norfolk Broads, I walked another seven days across landscapes so low-lying that they’re already below the level of the rivers passing through them, and only kept dry by complex systems of drainage and defences.
As we continue to worsen climate change by burning fossil fuels, all these places will become harder and more expensive to defend – until the day they can’t be defended any more.
Flooding and erosion are not new threats to the Norfolk coast.
At King’s Lynn Minster, in Blakeney and elsewhere, commemorative stones mark the height of the deadly floods of 31 January 1953 (when 531 people died on land and at sea in the UK), 1978, and 2013. After each flood, defences have been built up and alert systems improved, but residents of these areas live under constant threat.
Just this month, as I was walking there, a surge following storm Agnes added to very high tides which breached the harbour wall at Wells-next-the-Sea and left hotel guests in Blakeney trapped in their rooms.
With climate change the threat is becoming more severe, but predicting the precise timing of future impacts is essentially impossible. That’s because the future of these areas isn’t simply dependent on rising sea levels, but also the changing severity and frequency of storm surges and the continuation (or otherwise) of investments in coastal defences. Forecasts of each are racked with uncertainty and imprecision.
Increases in sea levels are driven primarily by burning fossil fuels, which is heating the planet and causing the thermal expansion of seawater, while adding to it by melting glaciers and icesheets. The rate of sea level rise has been increasing, from 1.3 mm a year prior to 1971 to 3.7 mm a year in 2006-2018, but future sea levels depend to a large extent on the rapidity with which we decarbonise and stop adding heat energy into our planetary system – and there remains huge uncertainty over how quickly the nations of the world will do so.
Moreover, the precise relationship between planetary heating and sea level rise is so complex and poorly understood that it is difficult to forecast future increases even if we could foretell the success of decarbonisation efforts.
While the Intergovernmental Panel on Climate Change predicts between 50 cm and one metre of sea level rise by the end of the century (i.e. within the lifetimes of people already born), depending on our global level of emissions, it cannot rule out the possibility of “low-probability, high impact” scenarios caused by the destabilisation of icesheets, which could add an additional metre within the same timeframe.
Higher sea levels, of course, lead to higher tides, but it is not simply the highest tides that cause most flooding and erosion – rather, this happens when high tides are accompanied by extreme weather events such as storm surges. These too are difficult to predict because they are naturally highly variable and their infrequent nature means we don’t have much data, but in Britain and northern Europe extreme surges are now twice as likely to occur as they were in 1960, and are expected to become more extreme with worsening climate change.
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Complicating the picture further, the future of many areas depends not only on sea level rise and the increasing severity of storm surges, but also our continued capacity to defend against them. The costs of maintaining defences will of course increase as impacts worsen, but continuing to do so indefinitely is not an option for most places, and difficult decisions are already having to be made.
At Heacham in West Norfolk, coastal communities are protected by a five-mile shingle ridge at the back of the beach, but the area’s shoreline management plan states that “continuing the current approach of using the shingle ridge as a frontline defence will be difficult beyond the short-term”. The plan’s ‘hold the frontline’ policy remains in place until 2025 but will be reviewed next year: if maintaining defences is found not to be feasible or cost-effective, the policy will be replaced with one of ‘managed realignment’, homes and caravan parks will be moved inland, and the sea will be allowed in.
Yet residents of Heacham may see themselves as comparatively lucky – across much of eastern Norfolk the Environment Agency has a policy of ‘no active intervention’ away from the largest towns, and there’s no investment going into defences whatsoever. As a result, the land is in rapid retreat and coastal residents live in perpetual fear that the next bit winter storm may bring the end of their homes.
Though there’s great uncertainty over precisely when different parts of lowland England will be lost to the seas, it is absolutely certain that it will happen if we continue to burn fossil fuels and supercharge our atmosphere and oceans with heat energy.
To have any hope of saving our precious coastal places and low-lying inland areas, we need to get off fossil fuels as soon as possible. That makes this Government’s recent decision to greenlight exploitation of the Rosebank oilfield, as well as backtracking on decarbonisation policy commitments, more than just a slap in the face for residents in vulnerable places. As many I spoke to on my walk made clear, they feel like they’ve been forgotten and abandoned.
Charlie Gardner is Associate Senior Lecturer at the Durrell Institute of Conservation and Ecology, University of Kent