The coastline of Holderness consists of unprotected
boulder clay cliffs which have been subjected to heavy erosion from the sea. Detailed analysis shows that much of the material lost from Holderness is swept down the coast to be deposited on
Spurn Head. It is estimated that since
Roman times, at least 30 settlements have been washed away by the action of the sea, with the boulder clay of the Holderness Coast being particularly susceptible to erosion. Coastal erosion on the Yorkshire coast has long been acknowledged; the town of
Ravenser Odd, located south and east of the present Spurn Head, was washed away by several high tides and sea swells in the 14th century, the lighthouse at
Withernsea, built in 1892, was located some inland due to the land at the coast being sand dunes and constantly eroded, and a book published in 1912,
The Lost Towns of the Yorkshire Coast, estimated that the coast had been eroding at a rate of a year. However, detailed study of mapping has indicated that between 1852 and 1952, the rate was at a lesser loss of on average each year. The harder rocks of the North Yorkshire coastline (assessed between the mouth of the
Tees and
Ravenscar), retreated at a loss rate of during the same period. Settlements along the North Yorkshire coast have been partially lost to the sea; the main road into the seaside village of
Robin Hood's Bay was lost in 1780, and most of the village of
Kettleness was lost in December 1829. Throughout the early part of the 20th century, houses were still being lost to the sea at Robin Hood's Bay; one story from 1946 tells of a woman sitting down to tea in her front room (facing westwards towards the landward side), and parts of the back of her house sliding into the sea. Further losses prompted the county council to build a seawall which is long, and high, costing £578,000 (). However, the loss at Kettleness was in part owing to alum quarrying on the shore below the clifftop village.
Whitby has historically suffered from coastal erosion, most notably on the cliff edge by
St Mary's Church, which has meant that some of the graves in the churchyard have been lost to the sea. A 2002 study suggested that the sea-level rise at the Yorkshire coast could be anywhere between and by 2080. However, a process known as
isostatic adjustment, means that when the ice sheets melt, the top half of the United Kingdom will raise up, and the southern tilt down. As a result, there will be fewer areas at risk in far north of North Yorkshire than in the East Riding of Yorkshire. The line of demarcation between the stable lands and those rising is said to run along the Tees Valley. A year–on–year average of a rising sea level has been the norm with isostatic adjustment, but coupled with
rising sea levels due to global warming, this year–on–year average is expected to be around the mark. In 2022, the chief executive of the
Environment Agency, Sir James Bevan, suggested that for coastal communities, such as those living on the East Riding coast (Holderness), moving away would be the only option compared to inland locations at the risk of rainfall flooding, where some preventative measures can be taken. The policy for coastal erosion is to allow all natural processes to continue as they are, and only focus anti-flooding measures such as sea walls and beach defences, on existing towns such as
Bridlington,
Hornsea and Withernsea. The Holderness coast is said to be being eroded at a rate of per century due to its glacial drift geology, whereas the North Yorkshire coast between Whitby and Redcar is estimated to be retreating at a rate of per century. == Areas affected ==