Millions face long-term coastal flooding risk in UK without climate action, scientists warn

Coastal erosion in Withernsea, East Yorkshire. Lincolnshire and the Humber estuary are the areas most in danger. Photograph: Christopher Furlong/Getty Images View image in fullscreen Coastal erosion in Withernsea, East Yorkshire. Lincolnshire and the Humber estuary are the areas most in danger. Photograph: Christopher Furlong/Getty Images Millions face long-term coastal flooding risk in UK without climate action, scientists warn A ‘reasonable worst-case scenario’ suggests need for large-scale movement of populations away from reshaped coast Up to 13 million people in the UK face the long-term risk of coastal flooding due to the climate crisis, scientists have warned, with a “reasonable worst-case scenario” suggesting the need for the large-scale movement of populations away from a dramatically reshaped coast. Even if today’s global pledges to cut carbon pollution are met, about 1.4 million more people will be exposed to coastal floods in 2200 and 1.7 million in 2300 due to the sea level rise driven by melting ice caps and warming oceans. While this is far in the future, action today to cut emissions and plan future settlements and flood defences could prevent such leaps in flood risk becoming inevitable, the experts said. Keeping within the Paris agreement targets would cut the number of people exposed in 2300 by 1 million, they said. Sea level has risen by about 20cm around the UK in the last century and is accelerating. A further 40cm to 60cm by 2100 is already baked in, meaning about half a million more people will be at risk of their homes being flooded, on top of the 2.5 million already in danger near the coasts. Lincolnshire and the Humber estuary are most in danger. ‘Severe’ stress on oceans as rate of sea level rise doubles in 10 years, UN warns Read more However, scientists are concerned that the gradual rise in sea levels seen so far could change rapidly if ice sheets start a runaway collapse into the oceans, instead of just melting slowly in place. In this scenario, the UK could suffer 15 metres of sea level rise by 2300, swamping large parts of London and many other places, the researchers found. “[Planners] who only consider changes over the coming century may have a false impression of the true risk landscape given the potential for post-2100 acceleration of sea level rise,” the researchers concluded in their study published in the journal Nature Communications . “It is inevitable that a combination of additional or enhanced flood defences and managed retreat will be necessary to mitigate against post-2100 flood risk.” Map of flood risk scenarios around the UK coast Prof Matt Palmer at the University of Bristol, who led the research, said: “The oceans and ice-covered parts of the world respond very slowly to global warming, which makes sea level rise the ‘sleeping giant’ of climate change. The result is that sea-level rise is locked-in for centuries to come.” Dr Rob Larter, at the British Antarctic Survey and not involved in the stu