Yorkshire & Humber Climate Change Adaptation

Here you will learn about the impacts expected from climate change by the 2050s on coastal evolution. This primarily relates to coastal erosion, but also considers accretion and other changes in features as a consequence of climate change where appropriate.

Description
The Yorkshire and Humber Region is characterised along its eastern margin by a stretch of coastline which abuts the North Sea. This coastline runs in a general north-west to south-east alignment and predominantly is characterised by sea cliffs with fronting wide sandy beaches or shore platforms with varying amounts of sand, pebbles, cobbles or boulders. At the southern end of the region the coastline is intercepted by the mouth of the Humber estuary, with Spurn Point, a large spit, attached to the northern mouth.

The coastline is strongly influenced by lithology (geological strength and structure) and the presence (or absence) of coastal defences.

Along the open coastline and estuary shore, there are urban conurbations, smaller coastal communities, areas of intensive industrial and port use, active fishing communities and more rural areas where agriculture and/or tourism dominate.

Offshore, the sea bed is relatively deep quite close to shore, meaning that the marine environment is very energetic and tidal currents and wave energy can be strong, particularly during high sea swells and storms.

The Yorkshire and Humber region’s coastline and estuarine shores are vulnerable to erosion due to:

Marine processes, such as wave action and sea level rise;
Sea cliff instability triggered by marine processes or by groundwater pressures; and
Weathering due to freeze-thaw cycles, abrasion, wind stress, and so on.

The rate of erosion of the coastline is governed by the magnitude of the forces generated by the above processes relative to the strength of the underlying sediment type.

With climate change, rising sea levels and changes in tidal surges and wave storminess will all modify coastal processes and, overall, increase marine erosion.

In addition, changes in rainfall and temperature are likely to combine to worsen existing patterns of sea cliff instability (which is usually triggered by intensive rainfall events in softer rock strata, especially clays) and weathering of hard rock sea cliffs and shore platforms.

Impacts
The principal impacts from climate change to the Yorkshire and Humber region’s coastline and estuarine shores by the 2050s will be:

Increased overtopping of coastal defences by waves and storm surges, causing more frequent sea water flooding to promenades and backing assets (houses, industry, recreational facilities, etc.);
Increased rates of erosion on areas of coast which have softer substrates (e.g. soft rock cliffs, sandy beaches, estuarine flats and marshes) caused by higher wave and tidal energy, leading to:

loss of land including valuable Grade 5 agricultural land and important amenity areas;
loss of associated cliff-top assets including the economically-important caravan parks;
loss of habitat, including internationally important inter-tidal habitat in low-lying areas such as the Humber Estuary which will require compensatory habitat to be re-created elsewhere under European legislation.

Increased seasonality in beach level changes, including changes associated with increased winter flows from the rivers that discharge in to the sea at the coastline;
Increased ‘squeezing’ of marine habitats between a rising sea level and a static backstop in the form of coastal or estuarine defences or hard rock cliffs;
Emergence or loss (due to erosion or submergence) of key controlling features, such as areas of harder rock geology forming headlands, or rocky platforms being submerged by rising sea levels, as the coastline generally erodes landwards;
Increased movement of sediments under higher wave energies, leading to beach lowering and inter-tidal habitat change, or areas of unwanted siltation in more quiescent areas (e.g. in harbour mouths, port channels, and marina berths) that would require increased dredging in order to maintain navigation; and
Increased risk of failing EC Bathing Waters standards due to reduced dilution of sewage and surface water outfall discharges to rivers by reduced summer flows and increased bacterial growth within water bodies during warmer summers.

In addition to this, with rising temperatures, there is likely to be increased tourism pressure on the region’s beaches, particularly in destinations such as Scarborough and Whitby. This will bring business opportunities, but also pressures on the fragile coastline from tourism and housing development in coastal locations potentially at risk from erosion or landslips which will need to be carefully managed. It will also placed increased demand on existing water supplies and waste water treatment capacities.

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| North Yorkshire | Humber|

Description
The North Yorkshire sub-region has a large stretch of ‘open’ coastline, the entirety of which is under the jurisdiction of Scarborough Borough Council. It extends from Staithes Harbour to Speeton and largely is composed of sandy beaches backed by sea cliffs. The North Yorkshire coastline can usefully be sub-divided into the following sections:

Staithes Harbour – this frontage comprises the small tidal harbour of Staithes Beck, which is protected at its mouth by two breakwaters. The village of Staithes lies on the eastern side of the harbour, sheltered by the cliffed headland of Cowbar Nab, which is actually located beyond the Yorkshire and Humber region’s boundary within Redcar and Cleveland.

Penny Steel Headland to Cobble Dump, incorporating Port Mulgrave – this is predominantly a cliffed frontage with, in places, a shale beach formed by debris from landslides. There are remains of an old harbour at Port Mulgrave.

Runswick Bay – this frontage is formed between the headlands of Caldron Cliff and Kettle Ness and comprises a deeply-indented sandy bay backed by cliffs and, in places, glacial till slopes. The shoreline is intersected by Runswick Beck and Nettledale Beck.

Kettle Ness to Sandsend Ness – this section has been quite heavily influenced by former mining activities (ironstone, alum and jet), which in areas has resulted in lowering of the rock platform and in some places local subsidence of the foreshore leading to enhanced erosion.

Sandsend Bay – this is a shallow curving bay extending from Sandsend Ness to the rock outcrop at Upgang. It is fronted by a relatively wide sand beach and historically has been heavily modified by mining activities. Parts of the frontage are defended by a concrete seawall.

Whitby Sands – from Upgang Beck a graded coastal slope extends eastwards towards Whitby Harbour, grading into a sea cliff at the eastern-most end. The frontage is protected by a concrete wall and promenade, now upgraded with a fronting rock revetment.

Abbey Cliff – these high, near vertical cliffs extend from Whitby Harbour to Saltwick Nab and are protected at their western end by a rock revetment at the crook of the Whitby Harbour East Pier.

Saltwick Nab to Ness Point – this frontage comprises steep cliffs fronted by a wide rock platform.

Robin Hood’s Bay – this bay has been formed as a result of the differential hardness of the coastal margin. The frontage demonstrates a history of landslides through a series of steep but well vegetated terraces. The cliff face in front of the town has been stabilised through coastal defence works.

Ravenscar to Hundale Point – this frontage starts with a continuation of the complex coastal slope that is subject to landslips and consolidates to a more vertical and ultimately low cliff. The foreshore comprises a narrow rock-strewn beach overlying a rock platform.

Hundale Point to Scalby Ness – this frontage comprises generally steep cliffs overlain by glacial till. Some sections are highly indented, forming very shallow bays.

Scarborough North Bay – this is formed by the cutting back of the high glacial till coastal slopes between the Scalby Ness and Castle Hill headlands. The frontage is heavily defended and is intersected by Scalby Beck in its northern end.

Scarborough South Bay – this covers the main developed coastal resort area of Scarborough and is heavily protected by coastal defences along the urban frontage.

Cornelian Bay and Cayton Bay – these bays are composed of steep glacial till slopes and are controlled by intervening hard rock headlands, such as Osgodby Point. In Cornelian Bay the foreshore comprises high boulder-strewn rock outcrops forming a reef in front of the shoreline. Cayton Bay is characterised by a complex terraced landslip area with a fronting broad sandy foreshore.

Cayton Bay to Filey Brigg – this cliffline is very steep and, in many places, undercut by wave action. It has massive scree slopes down to a narrow sand foreshore behind a wide area of intertidal platform. The cliff reduces in height towards Filey Brigg and is characterised by rock falls.

Filey Bay – this cliffed bay extends between Filey Brigg, an outcrop of hard Jurassic rock overlain by glacial tills, and Flamborough Head, with its chalk cliffs overlain by glacial till. Note that the boundary between the North Yorkshire and Humber sub-regions falls mid-way along this section at Speeton. South of Filey Brigg, but to the northern end of Filey town, the deeply-incised Church Ravine intersects the coastline. Filey town is protected by coastal defences. Further south, towards Flat Cliff, the coastline is punctuated by Primrose Valley ravine. The behaviour of the cliffs changes from simple landslip slumps to terraced landslip complexes at various locations along the frontage.

The North Yorkshire coast is particularly vulnerable to:

Cliff erosion and beach lowering due to wave energy and sea level rise at the cliff toe;
Cliff instability due to increased winter rainfall;
Wave overtopping of coastal defences due to sea level rise;
Landward migration and lowering of beach systems due to rising sea levels;
Development pressures at the coastal margin; and
Increased pressure for tourism and amenity use due to rising temperatures.

Impacts
Although located outside of the Yorkshire and Humber region, the erosion rates over the next 50 years of Cowbar Nab (in Redcar and Cleveland, North East Region) could have implications on the degree of shelter afforded to Staithes Harbour and village. In the absence of coastal defences, the natural tendency would be for Cowbar Nab to erode, although the rate of landward retreat over 50 years is not projected to compromise the headland and therefore the principal change in exposure within the harbour will be from increased wave and tidal energy propagating up Staithes Beck from the North Sea.

At Port Mulgrave increased sea levels and more intense rainfall patterns, especially during winter months, are likely to lead to increased landslips. This will be further exacerbated if the existing old harbour structures become obsolete and cease to retain beach sediment. Similarly, localised mudslides are likely to become more prevalent at Runswick Bay due to similar processes. In both areas the erosion would lead to loss of sections of the Cleveland Way long-distance footpath.

Between Kettle Ness and Sandsend Ness erosion rates will be relatively low, even when considering climate change, due to the lithology of the rock geology.

The coast road at Sandsend could be lost to erosion when considering future recession rates associated with sea level rise. This process would also affect sections of Whitby Golf Course. Defended sections of frontage will experience increased overtopping which could cause public safety issues and ultimately could cause structural damage during severe storms.

Along Whitby Sands the increased wave and tidal energy could lead to enhanced foreshore lowering which would expose the seawall and revetment to undermining and increased overtopping. The recently completed rock armouring at the toe of the wall will, however, reduce these impacts by breaking up the wave energy at the toe.

At Whitby Harbour, increased wave activity and sea levels will lead to increased overtopping of, and damage to, the existing harbour piers. This will have implications for public safety, requiring access to the piers to be restricted during high sea states, and also could enhance structural damage. There is a risk that the piers could breach due to their exposed positions and aged nature, leading to higher wave energy within the harbour which would have consequences in terms of both navigation and erosion. Also, under such a scenario, more beach material would be mobilised from Whitby Sands leading to increased siltation in the harbour and reduced beach levels at the toe of the seawall.

Whilst most properties within Robin Hood’s Bay are unlikely to be affected by ongoing coastal erosion and landsliding, some are likely to be lost to the northern end of the village. Also within Robin Hood’s Bay, the last few miles of the Coast to Coast footpath from Hawsker and further sections of the Cleveland Way would be lost to erosion. The frequency and, possibly, magnitude of single landslide events is set to increase with climate change, particularly during winter months when rainfall is projected to be greater and there is greater likelihood of sea storm surges occurring.

Left unchecked, cliff erosion between Hundale Point and Scalby Ness will lead to losses of further sections of the Cleveland Way and some agricultural land.

Along the Scarborough North Bay and South Bay frontages, there will be increased frequency of wave overtopping of defences due to rising sea levels. This will lead to increased local flood damage and disruption. The greater wave energy along the shore may also cause increased volatility in beach levels, more regularly exposing the toe of defences and reducing their structural integrity.

Within Cornelian Bay and Cayton Bay, increased sea levels and increased winter rainfall conditions are likely to lead to increased cliff instability and erosion, ultimately leading to loss of the Sewage Pump House at the northern end of Cornelian Bay, and loss of properties along the top of Cayton Cliff. Along Gristhorpe Cliff there will be loss of land belonging to the Caravan Park and along North Cliff loss of sections of the Cleveland Way long-distance coastal footpath.

Increased winter rainfall and rising sea levels will contribute to increased potential for reactivation of landslips along the coastline between Filey Brigg and Flamborough Head. The impact of this will be greatest at Flat Cliff, Hunmanby Gap and Reighton Gap where small communities and large tourist centres will be vulnerable and are all likely to be compromised or entirely lost to further slippages within the 50 year timescale being considered here. Also likely to be affected by these losses are a sailing club and land belonging to a golf course.

Whilst it is easy to characterise coastal erosion and increased likelihood of landslip as a series of losses of terrestrial features to the sea, theses natural processes also have a number of critical beneficial effects on the landscape and natural features of the coast. Much of the North Yorkshire coast falls within the North York Moors National Park and is highly valued by both visitors and local people for its dramatic coastal scenery which rely on the processes of coastal erosion and landslip. The Cleveland Way in particular gives walkers impressive views of eroding and slumping cliffs. The North Yorkshire coast is also internationally renowned for its geological sites including exposures of fossil beds, these are maintained in a condition suitable for scientific and educational study by coastal erosion. Instability on cliffs composed of softer rocks results in a unique mosaic of habitats such as woodland, scrub and species rich grassland with areas of exposed rock. These sites tend to be steep and inaccessible which allows wildlife to thrive undisturbed and can be particularly valuable for rare plants and invertebrates.

Further detail on the coastal erosion impacts that are anticipated by coastal managers within North Yorkshire over the next (nominally) 20, 50 and 100 years are presented in the River Tyne to Flamborough Head Shoreline Management Plan 2, which can be obtained from the following website: ‘www.northeastsmp2.org.uk’.

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Description

The Humber sub-region comprises a stretch of ‘open’ coastline between Speeton and Spurn Point at the mouth of the Humber, and also the estuarine shores of the Humber estuary. The frontage can usefully be sub-divided into the following sections:

Filey Bay – this bay extends between Filey Brigg, an outcrop of hard Jurassic rock overlain by glacial tills, and Flamborough Head, with its chalk cliffs overlain by glacial till. Note that the boundary between the Humber and North Yorkshire sub-regions falls mid-way along this section at Speeton. Between Speeton and Flamborough Head the coast is characterised by high vertical chalk cliffs, characteristically with a deposit of chalk boulders at the toe with little foreshore width.

Holderness coastline – this frontage extends from Flamborough Head to Spurn Point and comprises some of the most rapidly eroding cliffs in Europe (around 1.8m per year on average, higher in places locally). It is composed of variable height sedimentary cliffs fronted by mixed sand and shingle beaches.

Humber Estuary – comprising the tidal flats and marshes of the tidal reaches of this major estuary system.

The Humber sub-region’s coast is particularly vulnerable to:

Cliff erosion and beach lowering due to wave energy and sea level rise at the cliff toe;
Cliff instability due to increased winter rainfall;
Erosion of inter-tidal mud flats and salt marshes within the Humber Estuary;
Increased dynamism of Spurn Peninsula;
Wave overtopping of coastal defences due to sea level rise;
Landward migration and lowering of beach systems due to rising sea levels; and
Development pressures at the coastal margin.

Impacts
Between Speeton and Flamborough Head the cliffs will continue to experience erosion due to wave attack at the toe, but this will continue to be at only modest rates of recession due to the nature of the geology. Consequently, other than a narrow strip of cliff-top land, no assets will be lost.

South of Flamborough Head, undefended sections of coast will continue to erode. This is an important process as it provides material from the cliffs which feeds nearby beaches and the finer material is transported in suspension in the water column, much travelling into the Humber Estuary where it can become deposited on the inter-tidal flats and marshes, contributing to their natural response to sea level rise, and much bypassing the estuary and feeding the Lincolnshire beaches.

Along the Holderness coastline, cliff erosion will continue in the undefended areas and lowering of the foreshore platform will continue when uncovered by beach sediments. Increased winter rainfall, leading to slippages, and sea level rise may accelerate erosion rates compared to historic values. Whilst this would result in increased loss of agricultural and amenity land and caravan parks along the Holderness coastline, a positive impact, in terms of the continued release of sediment from the cliffs, would be the continued feed of sediment to existing transport pathways, helping the Humber estuary to respond dynamically to sea level rise.

Along the defended sections of the Holderness coastline, increased lowering of the foreshore platform may occur, exacerbating sea level rise effects and possibly leading to increased maintenance costs.

The greatest concern from this ongoing and accelerated erosion along Holderness, however, will be at Easington, where a principal component of the UK’s gas infrastructure is located on the cliff top. Although the site was protected against coastal erosion in 1999 with a finite-life (in planning terms) coastal defence scheme involving a rock revetment, cliff drainage and cliff re-grading, the exposure conditions (sea level, waves and rainfall) will continue increase over the next 50 years, leading to overtopping of defences and occasional erosion of the backing cliffs. As well as putting the terminal at increased risk from this process, the coastline either side of the defended stretch will continue to erode, leaving the defended section proud of the remainder of the coast and leaving the scheme vulnerable to erosion from outflanking.

At the mouth of the Humber Estuary, Spurn Peninsula will become increasingly dynamic in its behaviour in response to rising sea levels and increasing surge effects. There will be increased risk of temporary loss of the access road to Spurn Point due to localised erosion or temporary breaching but it is considered unlikely that Spurn Peninsula would be breached permanently or lost entirely by the 2050s. This was, however, identified as a potential longer term outcome by the Futurecoast (Future Coastal Evolution around England and Wales) study (Defra, 2002). If Spurn Peninsula were to be breached or lost, there would be major implications at the mouth of the Humber Estuary in terms of wave propagation, sediment transport and tidal flows that would need detailed consideration.

Within the Humber Estuary, sea level rise will generally lead to erosion and redistribution of sediment. This will typically involve landward retreat of the salt marsh edge and deposition of sediment on the upper marsh, thereby moving the inter-tidal zone seaward and upwards with respect to the tidal frame. Where existing defences or rising ground back the marshes, as is the case over the majority of the estuary, this processes would lead to coastal squeeze and loss of inter-tidal habitat area. This has significant implications in terms of the loss of internationally designated habitat which, under the EU Habitats Directive and associated UK Habitats &c. Regulations, would require compensatory habitat to be re-created elsewhere within the Humber Estuary in order to offset the losses.

A positive impact from erosion of the adjacent Holderness coast will be the delivery of sediment into the Humber to enable the inter-tidal areas to keep pace with sea level rise through ongoing vertical accretion, despite the erosion of the landward erosion of the marsh edge described above.

Further detail on the erosion impacts that are anticipated along the open coastline by coastal managers within the Humber sub-region over the next (nominally) 20, 50 and 100 years will be presented in the Flamborough Head to Gilbraltar Point Shoreline Management Plan 2, which will be obtainable from the following website: ‘www.hecag-smp2.co.uk’. This document is expected to be completed by the end of 2009.

In addition, further detail on the erosion impacts that are anticipated along the estuarine shores by flood risk managers within the Humber sub-region over future decades is presented in the Humber Flood Risk Management Strategy (Environment Agency, 2008) which is available from the Environment Agency.

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