What is UKCP18?
The UK Climate Projections 2018 (UKCP18) are state-of-the-art projections that provide insights into future changes in temperature, precipitation and sea level (amongst other things) across the UK. This is the first revision for nearly a decade.
What does it mean for our coasts?
For centuries, sea level has been relatively static. Towns and cities have expanded along our shorelines, placing homes and infrastructure as close as possible to the sea. Problems have arisen but, on the whole, these have been met through ‘hard’ engineering; the construction of seawalls and revetments to prevent the sea flowing onto the land, and to stop cliffs and beaches being washed away.
The new projections show us that regardless of how the nations of the world respond to climate change, the sea will rise at greater rates than any seen throughout human history. This rise is forecast to be greater than previously thought, and will continue for a long time; at least the next three hundred years, and probably much longer.
In London, for example, under the upper limit of the high emissions scenario, sea levels are projected to rise by more than 1.1m over the next 80 years (around a quarter of a metre higher than was previously thought). By 2300, this rise will exceed 4m, and (as the science is still in development) greater rises have not been ruled out.
To people outside the world of coastal management this may not seem particularly problematic, at least over the coming century. Engineers can build bigger walls, and the economic value of land and assets in London (and other major cities) will surely justify the associated expense.
The situation is very different in less economically active coastal towns and cities where flooding and erosion, though dangerous and disruptive would not be of the scale that would, in themselves, justify investment in defences under our current assessment protocols.
In addition, such economic arguments around hard defences represent rather narrow thinking about the problem and potential solutions to it.
The social and environmental impact of installing extended concrete structures between coastal communities and their shoreline may be unpalatable. Sea views will be lost, residents and visitors will feel less connected to the coast, and many town beaches would ultimately be submerged leaving settings akin to exposed quaysides, with waves breaking on steep concrete walls rather than spilling gently across beaches.
Is there a solution?
In fact, an alternative strategy, of ‘No Active Intervention’, necessitating some form of adaptation, will soon become the recommended policy along around 500 km of our coastline.. Current planning and funding rules actually steer decision-making in this direction and, for some areas at risk, it would require significant changes to assessment protocols to change this direction. To let coastal processes run their course and thus to relocate communities as shorelines retreat may be the only truly sustainable approach in some areas. However, this would be hugely challenging both politically and economically.
The next steps…
We need to debate this issue. The scale and timeframe of the sea level rise projected by UKCP18 shows us that these challenges will be unavoidable in some areas. What is the right thing to do? Where do society’s obligations to potential coastal refugees lie? To what extent are they to be supported financially or socially? We need to have this conversation now to plan for the future, to inform existing policies and to develop new ones. Facilitating active relocation and preventing the overdevelopment of high-risk areas will give us a greater chance of coping with rising sea levels, as we learn to live with the changing coast rather than work against it.