Recent bad weather conditions have caused huge cracks to open up at the top of cliffs in East Sussex.
The National Trust says Britain's winter has caused the chalk cliffs at Birling Gap, near Eastbourne, to suffer around seven years of erosion in just two months and warned walkers to keep away from the cliff edge.
Jane Cecil, National Trust general manager for the South Downs, said of the cracks: "We are likely to see more emerging."
The Trust has warned that hard defences, such as sea walls, are unlikely to be the best solution to coping with the forces of nature on our coasts.
More long-term planning is needed to minimise the impact of the changing climate, it advised.