Challenges for Environmental Studies in a changing world

Professor Sue Brooks reflects on the current challenges faced by geographers and environmental managers as we see continual changes to our environment.

Environmental Change

Our constantly changing environment presents many challenges and opportunities for research and education in the Higher Education sector. Climate change is rarely out of the news, issues of environmental pollution and food security have never been more prescient than during the current COVID-19 pandemic, and our collective impact on wildlife will surely be highlighted by an ongoing unprecedented crash in visitor numbers to Areas of Outstanding National Beauty, Sites of Special Scientific Interest and Special Areas of Conservation. One area presenting particular challenges to Geographers and Environmental Managers is that of understanding rates and mechanisms of coastal change under accelerating sea level rise and changing storminess, whether that be through changing storm intensity, magnitude or direction of travel with respect to coastal orientation.

Retreating Cliffs

Understanding coastal and environmental change is something our undergraduates at Birkbeck, studying for BSc degrees in GeographyEnvironment & Sustainability, are encouraged to engage with throughout their programme. The first question we address is the extent to which our environment is changing. Taking the coast as an example, we can use aerial and ground-based Earth Observation data to develop feature layers for successive periods of time which can be compared and overlaid to assess and quantify change. Take the retreating cliffs of Suffolk shown in Figure 1, where the changing feature is the clifftop edge.

Figure 1: The retreating cliffs at Covehithe Suffolk (7 May 2018) showing evidence of rapid retreat and high process energetics

Figure 1: The retreating cliffs at Covehithe Suffolk (7 May 2018) showing evidence of rapid retreat and high process energetics

These cliffs at Covehithe, Suffolk are retreating very quickly as evidenced through the close proximity of the path to the edge, the clean face of the near-vertical cliffs and

A historical map/aerial photograph

Figure 2: Quantifying shoreline retreat rates over historic and contemporary timescales, using historical maps and aerial photographs. Shorelines are digitized from maps and aerial photos and superimposed on a reproduced 1948 map (shoreline dates from 1947). Red dot indicates the area of figure 1, and solid black line indicates region of detailed shoreline change analysis.

the clifftop edge vegetation indicating instability and the presence of cracks. But how fastare these cliffs retreating? We can address this question by looking at Ordnance Survey historical maps, in this example dating from the 1880s and 1940s. But we can also overlay aerial photos from more recent years, here we use 1993, 2000 and 2010. Expressed in meters of retreat per year (ma-1), the average retreat from 1883 to 1947 was 2-2.5 ma-1 for the cliffline emphasised in bold in figure 2. Ongoing research as part of the BLUEcoast NERC-funded project has quantified a total retreat of 94m between 1993 and 2018 (25 years), at an average annual rate of 3.76 ma-1. The impact of recent high magnitude storms, such as “Beast from the East” and the 2013 North Sea surge reveals as much as 10-12 m of retreat can happen in single events.

Coastal Barriers

Retreating cliffs cannot return to their original locations. They provide a vital source of sediment that is pumped into the nearshore zone during episodes of high retreat and then is recirculated to create mobile barriers elsewhere. This highlights their importance to coastal management and the need to have sound process understanding for future planning. Behind the shoreline barriers diverse habitats thrive, routeways can be maintained and coastal communities are protected. A good example of a shoreline barrier is Blakeney spit, North Norfolk, shown in figure 3.

The Blakeney shoreline barrier

Figure 3: The Blakeney shoreline barrier, North Norfolk showing extensive areas of protected low-lying land behind the barrier. Also shown is an extensive washover feature that resulted from the surge on 5 December 2013 (maximum recorded water levels of 6.30 m ODN (Ordnance Datum Newlyn = approximately mean sea level). Retreating cliffs at Weybourne can be seen in the far distance. (photo: 23 July 2019).

Given sufficient sediment, barriers can grow with sea level rise to be able to withstand to an extent future challenges from storms. However, the largest, intense storms create barrier washover, rollover and breaching. These processes set the shoreline back and can lead to extensive flooding of the back-barrier. The coast exists in a finely balanced state between sediment sources (cliffs) and sinks (barriers), and the processes that connect them. Going forward we need to understand these sources and sinks, their changing locations and their interplay with habitats and communities. Management of coasts requires us to consider the processes that generate and deposit sediment and move it from place to place. At Birkbeck, our Programmes in Geography, Environment & Sustainability include modules that will enhance understanding and skills to address these issues. Consider applying if you want to learn more about our fascinating environment, the way in which it is changing and how to plan for future change.

Sue Brooks is a Professor of Coastal Geoscience in the Department of Geography.

She convenes 3 modules on the BSc Programmes in Geography, Environment & Sustainability:

  1. Introducing Natural Environments (level 4), 2. Environmental Processes (level 5) and, 3. Storms Seas and Rivers: Hydrology in the field (level 5).

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Responses to storm damage: research evidence for early warning and evacuation planning

This post was contributed by Dr Sue Brooks, Senior Lecturer in Physical Geography in Birkbeck’s Department of Geography, Environment and Development Studies.

Few people can have failed to notice the high flood incidence over the past few weeks across the UK. One particularly newsworthy event was the storm on 5-6 December 2013 that brought widespread coastal flooding into the southern North Sea and spread destruction across Europe.

Flooding on the North Norfolk Coast following the storm of 5-6 December, 2013 (photos courtesy of Mike Page)

Flooding on the North Norfolk Coast following the storm of 5-6 December, 2013 (photos courtesy of Mike Page)

Photo courtesy of Mike Page

Photo courtesy of Mike Page

The worst in 60 years?

The 5-6 December storm forced evacuation of over 10,000 homes in Norfolk and Suffolk, flooded over 1, 400 properties and caused houses to collapse into the sea. It appears to have been the most serious storm for 60 years, following the notorious storm surge of 1953 when over 2000 people lost their lives. But it could happen again next week, next month or next year – so we need to heed the lessons from both events.

Lessons from 1953

So how do these two storm events compare, why did the earlier event lead to such greater human cost and what can new research on the 2013 event tell us?

The 2013 and the 1953 storms arose in similar ways involving deep low pressure systems tracking down the North Sea. But the 1953 event, with eight metre waves, also had devastating consequences because it struck over a weekend. Early warning and evacuation planning were piecemeal, with the radio warning ceasing to transmit from midnight on the Saturday and the offices set to receive telegrams being shut for the weekend. People had very little warning. In 2013, in view of lessons from 1953, the sea encountered strengthened and heightened flood defenses, better early warning and better co-ordinated evacuation planning.

How our research is providing new lessons for early warning and evacuation planning

Following the 5-6 December storm we wasted no time recording its coastal impact. A team of researchers from Birkbeck and the University of Cambridge documented water levels around the coast of East Anglia. We used debris drift lines (we had to be quick as the tidy up was swift), erosional notches in banks and cliffs (these are preserved for longer), water marks on buildings and anecdotal evidence from local residents to position the water levels.

Drift lines and water lines on buildings in the immediate aftermath of the storm recording water elevations at Burnham Overy Staithe, Norfolk (photo taken on 6th December, 2013 by T Spencer)

Drift lines and water lines on buildings in the immediate aftermath of the storm recording water elevations at Burnham Overy Staithe, Norfolk (photo taken on 6th December, 2013 by T Spencer)

Water line evidence on public toilet block at Brancaster Beach, Norfolk following 5-6 December storm surge (photos taken on 6th December, 2013 by T Spencer)

Water line evidence on public toilet block at Brancaster Beach, Norfolk following 5-6 December storm surge (photos taken on 6th December, 2013 by T Spencer)

Brancaster Beach Sign

We used a Global Navigation Satellite System (GNSS) accurate to 20mm to determine the precise water elevations. We found 2013 water levels very similar to those of 1953, and in places 1953 levels were exceeded. More exciting was to find considerable variation in the water level around the coast, about two metres difference in North Norfolk.

Why was the water level so variable?

Water levels recorded in tide gauges in sheltered locations show how the surge level became progressively higher and occurred later as the storm moved southward (see diagram). Surge models can predict this effect and can thereby generate early warning and evacuation procedures against imminent flooding. However, they can only operate at this broad regional scale.

Recorded and predicted water level at locations along the east coast of UK, 5th-6th December 2013 (based upon data from the National Tidal and Sea Level Facility, provided by the British Oceanographic Data Centre and funded by the Environment Agency)

Recorded and predicted water level at locations along the east coast of UK, 5th-6th December 2013 (based upon data from the National Tidal and Sea Level Facility, provided by the British Oceanographic Data Centre and funded by the Environment Agency)

Strong, persistent winds generate high waves, also a factor in coastal damage. Waves were four metres at the Blakeney overfalls wave rider buoy (10 km offshore). Waves are considerably modified by the coastal setting. Along the North Norfolk Coast they were able to add significant force on top of already elevated water levels.

The collapsing cliffs at Covehithe, Suffolk (research will quantify the land loss in the 5-6 December, 2013 storm surge) (photo taken on 11th December, 2013 by SM Brooks)

The collapsing cliffs at Covehithe, Suffolk (research will quantify the land loss in the 5-6 December, 2013 storm surge) (photo taken on 11th December, 2013 by SM Brooks)

Further around the coast in Suffolk we found evidence for cliff erosion, arising from wave action at the cliff base (Brooks et al., 2012). Our initial findings suggest that water levels and wave action reached almost four metres ODN (Ordnance Data Newlyn, which approximates to mean sea level), producing notching and cliff collapse. Loss of land and homes through cliff retreat is irreversible and cliff retreat can continue long after the surge event has happened.

What lessons can we take forward from 2013?

  • Water elevation differences affect a property’s flood risk.
  • Homes and businesses need to have information on their specific vulnerability.
  • Models provide general predictions of timing of surges and open sea water levels.
  • We don’t currently consider how surges interface with the coastal setting encountered.

From 2013 we have now learnt that in coastal settings such as North Norfolk and Suffolk, the barrier islands, dunes and gravel spits, interspersed with tidal inlets with marshes and mudflats and separated by eroding cliffs make for huge variability in the potential for the sea to ingress and flood land, as well as to cause cliff retreat through wave action.

Our results show there are still lessons to be learned that could help prevent future societal and environmental damage that accompanies storm surges.

The team’s initial assessment is published in Nature and further information is available here.

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