̽��ֱ�� of Cambridge - Tom Spencer

Building a more sustainable world

skbf2 — Thu, 19 Sep 2024 10:21:27 +0000

This longstanding partnership between Cambridge, Arup and the Ove Arup Foundation has made our world safer and more sustainable and changed the way professionals are taught.

Sea change for Hull

lw355 — Fri, 16 Dec 2022 08:55:44 +0000

With a changing climate and rising sea levels putting cities at risk of flooding, it’s crucial for planners to increase their cities’ resilience. A new tool has been developed to help them – and it started with the throwing of a thousand virtual hexagons over Hull.

Sea Change

sc604 — Fri, 22 Mar 2019 09:13:26 +0000

̽��ֱ��coast is an intrinsic part of British identity – and perhaps nowhere is it more at risk than in the East of England. Cambridge researchers are working with communities and organisations across the region to manage the coast for the future, by working with nature rather than against it.

Britain from the Air: 1945-2009

sjr81 — Thu, 21 Feb 2019 17:25:21 +0000

Aerial photographs of Britain from the 1940s to 2009 – dubbed the ‘historical Google Earth’ – have been made freely available online.

Opinion: Methods for protecting England’s coastal communities ‘not fit for purpose’

Anonymous — Wed, 07 Nov 2018 16:42:50 +0000

In October 2018, a stark report suggested that current methods being used to protect England’s coastal communities are ‘not fit for purpose’.

̽��ֱ��Committee on Climate Change’s Managing the coast in a changing climate report showed that between 2005 and 2014, over 15,000 new buildings were built in coastal areas at significant risk of coastal flooding and/or erosion.

However, if the government meets its ambitious housing targets, up to 90,000 homes built in the next five years might be in areas of significant annual flood risk from all sources of flooding, including coastal flooding.

Practically every winter we are reminded of how dynamic our coastline is. And many of us see at very close quarters how vulnerable many communities in the UK are to coastal flooding and erosion.

But by the time summer arrives, the need for a wide and deep debate as to how we deal with rising sea levels and potential future increases in maritime storminess around the UK coastline evaporates.

Our approach to coastal management issues is to react to failures of coastal defences, either natural or man-made, rather than proactively working towards future-proofing our coastline.

Much of the UK coastline is already eroding, as testified by the dominance of coastal cliff scenery. But coastal erosion and flooding, and consequent damage to infrastructure, disruption of services and modifications to the coastal landscape will become more common over the next century due to climate change.

Specifically, rising sea levels will increase the probability of extreme coastal water levels and this could be exacerbated by potentially larger and more frequent extreme waves due to changes to the wave climate.

At the same time, our coastal zone is far from natural, with numerous clifftop properties and extensive development at the back of beaches, on top of dunes and in low-lying coastal valleys. It is obvious that coastal communities are facing significant future challenges.

Much existing coastal development took place when our understanding of coastal dynamics was limited and when climate change, and its consequences for the coast, was not yet a reality.

That development is already under threat, and the scale of the threat will only increase. Dealing with this issue requires a balanced consideration of the various adaptation strategies, ranging from ‘hard’ coastal protection such as sea walls to more sustainable solutions such as supplementing the amount of sand and gravel on our beaches, and managed realignment.

There will always be locations where only hard coastal defences will do.

But if we wish to avoid piling ever-increasing costs – in both financial and environmental terms – on future generations, we need a more sophisticated, integrated discussion of zoning (to avoid building in high-risk zones).

It may be stating the obvious, but a relatively easy win is to avoid more development in the dynamic coastal zone unless it is absolutely essential.

̽��ֱ��concept of Coastal Change Management Areas (CCMAs) can play a key role here.

̽��ֱ��National Planning Policy Framework (NPPF) requires councils to identify CCMAs where rates of shoreline change are expected to be significant over the next 100 years, taking account of climate change.

̽��ֱ��first local plan to make use of CCMAs to inform coastal planning is in Cornwall, where the Newquay Neighbourhood Plan (NNP) is currently under consultation.

̽��ֱ��NNP recommends that proposals for development in CCMAs should only be supported where they are for “small, temporary structures that will not add to the erosion risk”, and rules out residential development.

Proposals for redevelopment, enlargement or extension of existing buildings that fall within the exclusion zone, and proposals to change the use of existing buildings into residential usage, will not be supported either.

In the NNP, the landward limit of CCMAs represents the estimated 100-year erosion line with an additional buffer of 10 metres. Another 2m buffer zone is added if the coastal path is located within the CCMA.

Continued investment into the coastal zone will reduce the natural capability of the coast to respond to hazards, while at the same time passing the financial burden of protecting such coastal development onto future generations.

In order to future-proof our dynamic coast, we need to implement an appropriate buffer zone to inform coastal planning decisions, and these buffer zones will need to be site-specific and science-based.

They would also require regular updating in light of new data, understanding and predictions of climate change and its consequences.

̽��ֱ��Committee on Climate Change’s report has demonstrated the scale of future potential problems, and our own research heavily supports their findings.

By implementing a CCMA-informed policy that is consistent on a national scale, potentially with the policy outlined in the NNP as a blueprint, we can better protect our coastlines now and for future generations.

A bold response to the world’s greatest challenge
̽��ֱ�� ̽��ֱ�� of Cambridge is building on its existing research and launching an ambitious new environment and climate change initiative. Cambridge Zero is not just about developing greener technologies. It will harness the full power of the ̽��ֱ��’s research and policy expertise, developing solutions that work for our lives, our society and our biosphere.

Professor Tom Spencer from Cambridge’s Department of Geography and Professor Gerd Masselink from the ̽��ֱ�� of Plymouth say evidence suggests there should be far stricter controls on coastal developments.

Christopher Martin

Teignmouth seafront

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Up to four-fifths of wetlands worldwide could be at risk from sea level rise

sc604 — Wed, 24 Feb 2016 08:38:49 +0000

Using a new model to measure the possible effects on wetlands on a global scale, the researchers, from the UK and Germany, modelled the impacts of different scenarios for sea level rise to the end of this century.

They found that even in the event of ‘low’ global sea level rise (around 30 centimetres), much of the world’s wetlands, particularly on ‘micro-tidal’ coasts, are vulnerable. Around 70 percent of the world’s wetlands are found on micro-tidal coasts, where the range between high spring tide and low spring tide is less than two metres, such as in the Mediterranean and the Gulf of Mexico. ̽��ֱ��results are reported in the journal Global and Planetary Change.

Across the globe, wetlands cover more than 750,000 square kilometres, an area more than three times the size of the UK. Coastal wetlands, which include salt marshes, mangrove forests and mud flats, protect against erosion and flooding, provide habitat and food for wildlife, improve water quality, support commercial fisheries, and can store large amounts of carbon.

“Wetlands are particularly sensitive to environmental change, and are being lost worldwide due to human activity, such as conversion to agriculture, and through the effects of climate change, including rising sea levels,” said Dr Tom Spencer of the ̽��ֱ�� of Cambridge’s Department of Geography, the paper’s lead author.

According to the Intergovernmental Panel on Climate Change (IPCC), it is very likely that sea levels will rise during the 21^st century, but by how much depends on a variety of factors, including thermal expansion caused by ocean warming, loss of ice in glaciers and ice sheets, and the reduction of liquid water storage on land.

̽��ֱ��Wetland Global Extent Index, published in 2014, estimates that between 1970 and 2008, natural coastal wetlands declined by nearly 50 percent. A main reason for the high vulnerability of coastal wetlands to sea level rise is coastal ‘squeeze’, a consequence of long-term coastal protection strategies, such as dikes. While dikes provide flood defence to coastal populations and infrastructure, they prevent wetlands from moving landwards and upwards: dikes leave them with nowhere to go.

Wetlands such as salt marshes are made up of grasses and shrubs and are sensitive to environmental change, whereas wetlands such as mangrove forests, since they are trees, are far more resilient, at least in the short term.

Previous attempts to quantify the risk to wetlands posed by rising sea levels have focused on small areas, or have only looked at wetlands being lost through ‘drowning’ of the plants and shrubs, and not at how wetlands will ‘migrate’ inland.

̽��ֱ��model that Spencer and his collaborators from the ̽��ֱ�� of Southampton and Middlesex ̽��ֱ�� in the UK, and the Geographisches Institut and the Global Climate Forum in Germany, have developed assesses biophysical and socio-economic consequences of sea level rise and socio-economic development, taking into account coastal erosion, coastal flooding, wetland change and salinity intrusion.

̽��ֱ��researchers used their model to look at three different sea level rise scenarios (low, medium and high), combined with different scenarios for dike construction (no dikes, widespread dikes and maximum dikes), and assessed what the effect on coastal wetlands would be for each.

They found that if global sea levels rise by 100 centimetres combined with maximum dike construction, global wetland losses may reach 78 percent. For a rise of 50 centimetres, between 46 and 59 percent of coastal wetlands could be lost. For sea level rise around 30 centimetres, wetlands in micro-tidal regions are the most vulnerable.

“What our model does is provide better-informed projections about what might happen to wetlands over the coming century on a global scale,” said Spencer.

One of the issues which the researchers looked at was the use of dikes, seawalls, levees and other forms of coastal protection, and finding the balance between protecting cities and infrastructure from flooding, and protecting the wetlands which also play a key role in flood defences.

“One of the key things this project shows is that we need integrated management of wetlands and coastal protections on a national and international scale,” said Spencer. “Because if you don’t, in many cases if you protect one section of the coast, all you’re doing is moving the problem somewhere else.”

Countering these potential wetland losses will require both global responses such as climate mitigation to minimise sea level rise, and regional responses such as the maximisation of accommodation space and sediment supply on low-lying coasts.

̽��ֱ��researchers have already begun working on the next version of their model, which will also consider the effect that storms have on wetlands.

̽��ֱ��research was supported in part by the European Union.

Reference:
Thomas Spencer et. al. ‘Global coastal wetland change under sea-level rise and related stresses: ̽��ֱ��DIVA Wetland Change Model.’ Global and Planetary Change (2016). DOI: 10.1016/j.gloplacha.2015.12.018

Researchers have modelled how wetlands might respond to rising sea levels, and found that as much as four-fifths of wetlands worldwide could be lost by the end of the century if sea levels continue to rise.

We need integrated management of wetlands and coastal protections on a national and international scale.

Tom Spencer

By Anthony Bley, U.S. Army Corps of Engineers [Public domain], via Wikimedia Commons

Wetlands in Cape May, New Jersey, USA

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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‘Unprecedented’ storms and floods are more common than we think

lw355 — Wed, 09 Dec 2015 10:48:44 +0000

A team of experts from the Universities of Aberystwyth, Cambridge and Glasgow have drawn on historic records to build a clearer picture of the flooding.

They conclude that 21st-century flood events such as Storm Desmond are not exceptional or unprecedented in terms of their frequency or magnitude, and that flood frequency and flood risk forecasts would be improved by including data from flood deposits dating back hundreds of years.

Dr Tom Spencer from the ̽��ֱ�� of Cambridge said: “In the House of Commons on Monday (December 7), the Environment Secretary called the flooding in north-west England ‘unprecedented’ and ‘consistent with climate change trends’. But is this actually true?

“Conventional methods of analysing river flow gauge records cannot answer these questions because upland catchments usually have no or very short records of water levels of around 30 or 40 years. In fact, recent careful scientific analysis of palaeoflood deposits (flood deposits dating back hundreds of years) in the UK uplands shows that 21st-century floods are not unprecedented in terms of both their frequency (they were more frequent before 1960) and magnitude (the biggest events occurred during the 17th–19th centuries).”

Professor Mark Macklin, an expert in river flooding and climate change impacts at Aberystwyth ̽��ֱ��, said: “UK documentary records and old flood deposits dating back hundreds of years indicate that these floods are not unprecedented, which means we are grossly underestimating flood risk and endangering peoples’ lives.

“In some areas, recent floods have either equalled or exceeded the largest recorded events and these incidences can be ascribed to climate variability in Atlantic margin weather systems.

“It is of concern that historical data suggests there is far more capacity in the North Atlantic climate system to produce wetter and more prolonged flood-rich periods than hitherto experienced in the 21st century. Looking forward, an increased likelihood of weather extremes due to climate change means that extending our flood record using geomorphology science must be placed at the centre of flood risk assessment in the UK.”

Professor Macklin suggests that new approaches to flood risk analysis be adopted to include instrumental, documentary and most importantly palaeoflood records.

He added: “Current approaches using flood frequency analysis and flood risk assessment based on 40-50 year long flow records are far shorter than the design life of most engineering structures and strategic flood risk planning approaches. They are not fit for purpose now, let alone in a changing climate.”

Professor John Lewin from the ̽��ֱ�� of Aberystwyth said: “What is needed, is far more resilience for already-developed floodplains, and much more serious insistence that future floodplain development should be virtually curtailed. Somewhere along the line floodplain development has been allowed by local authorities and the UK government to continue regardless.”

Dr Larissa Naylor from the ̽��ֱ�� of Glasgow said: “These floods and the 2013/14 storms have shown us that our landscape is dynamic rather than static – where rivers reshape floodplains and erosion remodels our coastline – with large economic and social costs. We need to urgently consider how we plan our cities and towns, and rebuild in the wake of large flood and storm events, to live safely in our changing landscape.”

Spencer, Lewin, Macklin and Naylor are members of the British Society for Geomorphology’s Working Group on Stormy Geomorphology, who are currently finalising a global state-of-the-art analysis of the role geomorphology science can play in an age of extremes in the Wiley journal Earth Surface Processes and Landforms.

̽��ֱ��recent ‘unprecedented’ flooding in north-west England might be more common than currently believed, a group of scientists has warned.

Analysis shows that 21st-century floods are not unprecedented in terms of both their frequency and magnitude."

Tom Spencer

Gavin Lynn via Flickr

Flooded lakehouse, Keswick, Cumbria, UK

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Cambridge researchers learn lessons from recent storm surge

jfp40 — Thu, 16 Jan 2014 12:20:31 +0000

̽��ֱ��wet and windy weather that has battered Britain’s coasts this winter has brought misery to many, but for researchers at the ̽��ֱ�� at Cambridge the storm damage is providing vital data that could help improve future flood warnings and emergency planning.

On 5 December 2013, coastal communities along the North Norfolk coast were threatened by a significant storm surge – the result of low atmospheric pressure (which causes sea level to rise) combined with high winds pushing up the sea surface as they blow water towards the coast.

According to Dr Tom Spencer of the Department of Geography’s Cambridge Coastal Research Unit: “ ̽��ֱ��southern North Sea is very vulnerable to storm surges because of its shallow water, and winds blowing from north to south funnel the sea into the narrowing basin near the Straits of Dover.”

Predicting the impact of storm surges on coastal areas like North Norfolk, which is lined with barrier islands and gravel spits – and cut by tidal inlets bordered by mudflats and saltmarshes, is challenging. To find out how these features affected the water levels and waves that hit the area’s coastal settlements during the storm, the team from Cambridge and Birkbeck, ̽��ֱ�� of London took to the road.

Immediately after the surge, they travelled the 45km between Holme-next-the-Sea and Salthouse measuring maximum water levels with a satellite-based survey system able to resolve positions and heights to an accuracy of less than 50mm and often less than 20mm. “We looked for debris lines, erosion marks on earthen banks and floodlines on buildings – or in some cases car windscreens,” Dr Spencer explained.

They found that maximum surge heights here differed by almost 2m, depending on whether the site was exposed or sheltered, differences much larger than previously thought. “At some sites this was the critical difference between a business or a home being flooded or not,” said Dr Spencer. If these results can be incorporated into surge models and flood forecasts, they could help improve early warning systems and evacuation planning.”

̽��ֱ��December 2013 event that Dr Spencer studied came almost exactly 60 years after the disastrous storm that hit the region in 1953, claiming more than 2,000 lives around the southern North Sea – the largest death toll from flooding in Europe for 100 years.

“Looking at the atmospheric pressure charts, the 2013 and the 1953 events look similar: both were characterised by a deep low pressure system that came down the long axis of the North Sea. But while the 2013 storm was short-lived, producing waves of around 3.8m offshore from North Norfolk, in 1953 gale force winds blew for several days ahead of the surge, producing waves probably close to 8m high off eastern England,” he says.

Like the 2013 event, the 1953 storm arrived under cover of darkness. But unlike 2013, it hit over the weekend, with devastating results.

“Most people in the UK and ̽��ֱ��Netherlands were asleep in bed when floodwaters broke into their houses, many of which were single storey chalets and bungalows. Some people managed to get onto their roofs but, with the storm still raging, they died from exposure or slid into the sea,” he said. “In ̽��ֱ��Netherlands, where over 1,800 lives were lost, the radio ceased transmitting at midnight on the Saturday and although warnings were issued by telegram, these arrived at offices that were shut over the weekend.”

Much was learned from the 1953 storm: coastal defences were heightened and strengthened, and there have been major advances in storm surge forecasting and emergency planning. But, as Dr Spencer’s results show, there are still lessons to be learned from today’s floods that could help prevent tomorrow’s victims.

̽��ֱ��team’s initial assessment is published in Nature.

For researchers at the ̽��ֱ�� at Cambridge, recent storm damage is providing vital data that could help improve future flood warnings and emergency planning

These results could help improve early warning systems and evacuation planning

Tom Spencer

I Moeller

Stranded boat at Blakeney after storm surge

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