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Transcript of a talk by Sarah Morris, Head of Conservation & Maintenance, Historic Scotland

HEACS Conference on Climate Change, 25 September 2007

Introduction

This talk aims to highlight some of the issues which Historic Scotland faces, along with its partners, in preparing for the forecast impacts of Climate Change, both direct and indirect.

There is still some uncertainty, and perhaps even scepticism among the public, of the likely impacts of climate change, both on the historic environment and on our lives generally. It is of course not a new concept, our climate has seen many changes over the centuries, but the considered view is that we are facing a period of increased change and that in general things are not going to change for the better.

The medium to long term impacts are still difficult to predict and ongoing research across a number of areas will inform our actions for the future. The shorter term impacts are already with us with violent storms and localised flooding becoming a familiar sight on news reports. The impacts of these events are being seen in previously unaffected areas, and the intensity of the impacts appears to be increasing.

Historic Scotland of course has involvement across the historic environment as a whole. Our work as a government agency covers regulation, audit, advice, research and champion of all aspects of the historic environment. As Head of Conservation & maintenance for the Properties in Care, this talk covers our responsibilities as managers of the Estate, held in Historic Scotland's care on behalf of Scottish Ministers.

The Properties in Care

So I'm sure you will be familiar with at least some of the Properties in Care. There are 345 sites across Scotland covering a wide range of geographic locations and types of properties, and in reality covering many more than 345 individual structures or elements - Edinburgh Castle for example is a single property in care but consists of some 70 buildings or features. The properties in care are in a variety of states of preservation, ranging from roofed buildings, through roofless ruins to features buried underground.

Because of this wide variety of location, form and survival they can provide a useful barometer of some of the issues which climate change will raise. The main consequences of rising sea levels, increased storm intensity and flooding, have already had impacts on some of our sites over the centuries and seen their adaptation to change. We don't have all the answers, but we have experience of some of the issues which are emerging for the wider historic environment, and are actively engaging with partners to move forward on this important issue.

Coastal Erosion

One of the biggest impacts for Scotland is likely to be from rising sea levels and increased storm activity leading to an increase in coastal erosion. We have a very long and intricate coast and a long history of building settlements along it. Of course coastal erosion is part of a natural process which has been occurring since coasts were formed, constantly moving material by eroding one area and depositing in another, and we have an uphill struggle in trying to battle with the elements along our coast. Two of our higher profile sites which you will no doubt be familiar with are Skara Brae in Skaill Bay, Orkney and Fort George on a peninsula at Ardesier on the Moray Firth Built at very different times they are both vulnerable to tides and storms.

Skara Brae was of course discovered following a storm in the 1920s when the coastline was torn open, and we have been defending it ever since. A sea wall built in the 1930's and subsequently extended and altered several times, has been effective to date but requires frequent maintenance to ensure it remains effective. We have been closely monitoring the erosion of the dunes around the wall and modelling storm action on the site, but there is a limit to how much we can do for the longer term. We have completed a full recording exercise of Skara Brae as a backstop should a catastrophic event impact on the site.

Fort George sits on its peninsula in a prime location for its defensive purposes; and on a sunny day with the dolphins basking it is hard to believe there is any real problem, but the weather and tides have dramatic impacts in attacking the sea walls and moving large quantities of beach materials around. A recently uncovered stone-lined drain is protected by a simple, localised defence of timber posts driven into the beach to dissipate the wave energy. We have been experimenting with these as a solution to protect other small areas and have a long term programme of repairs to the masonry of the sea walls, but the tides can change their point of attack regularly so again we monitor closely and map the issues to inform and prioritise our defensive works, here and at our other sites.

Local defences can be effective in the short term, but often just move the problem further along the coast, and somewhere like Orkney moving the risk along the coast is likely to affect another important and fragile site. Coastal erosion represents the biggest environmental threat to archaeology at present, and sea level changes are the risk we are going to find most difficult to defend against.

We will be hearing later about the study which has so far mapped and investigated around 30% of Scotland's coast, to identify features and areas at risk. This will allow the prioritisation of resources to protect where it is viable, or to record details before they are lost. Larger coastal defence projects installed to address these aspects of climate change will be controversial. They will have major visual impacts and high costs which need to be balanced against the levels of risk. Rising sea levels are likely to increase the debate around the installation of these larger scale defences.

Flooding

The response to all types of flood risk requires the preparation of risk assessments to balance the likely impact on the environment with the likelihood of it happening. Though perhaps seen as a less significant threat, the increased and more concentrated rainfall predicted, together with river level rises and localised flooding are likely to have a wider impact on the historic environment, particularly the built environment.

For the Properties in Care Estate many of our sites were built beside rivers using them as a defence or a resource. Some are then on higher ground and are less likely to be directly affected, but here we can see Threave, on its low lying island in the River Dee and subject to man-made water level changes through a local hydro electric scheme. It copes with the current level changes, and the original moat and harbour are refilled by the rising levels without adverse impact, though there are times when our boat to take visitors to the island is not able to negotiate the fast flowing swollen river. The need for wellingtons at some sites when paths are flooded is a lesser hazard than perhaps those faced by the wider historic buildings stock, particularly in urban settings, where hard surfacing concentrates run off and allows fast moving overflows to affect wide areas.

Good maintenance is important in reducing problems but outdates infrastructure, and more rainfall means existing gutters, downpipes and underground drains are often not able to cope, and water can find its way into the fabric leading to water damage and rot. We've all seen the levels of damage from recent floods where combined drains discharged sewage as well as water into homes. Requirements to develop flood risk assessments, in response to the recent EU Floods Directive and the proposed Flooding Bill, recognise a range of adverse impacts on different factors, including the cultural heritage. Where identified flood risks can be addressed to divert floodwater these are now looking to sustainable flood management, using flood plains to dissipate water wherever possible.

Historic Scotland anticipates working closely with partners in further developing existing flood mapping using a range of datasets to assess likely levels of flooding, and to prepare the risk assessments to model outcomes and inform decision making and future flood management strategies. Historic town centres built along the banks of rivers are a challenge in this context.

Drought

The focus of much of the Climate Change story is on increases in the effects of water, whether by increased rainfall, flooding, or sea level changes.

Although we are likely to have increasing levels of rainfall it is possible they will be focussed at particular times of the year. The widespread forecast that this would be another long hot summer proved sadly wrong for Scotland, but last year showed us the effects of long spells of dry weather which are more widely predicted to affect the south of the UK. Extremely dry ground conditions can increase erosion, whether by footfall or by desiccation of buried material, and some materials are more prone to decay when they become over-dried, particularly if this is part of a cycle of wetting and drying which is likely to become more exaggerated. For many of the Properties in Care vegetation is a key part of the management of the sites, whether it be turf toppings to protect open wallheads or planting over archaeologically sensitive areas, and long dry periods can adversely impact the native species used.

Not an easy issue to illustrate here so I have chosen an illustration to show that dry spells can also have some advantages. Here at Dirleton Castle the 1865 garden layout is clearly visible in the 1920s lawn.

We are already facing an extended growing season which means we are maintaining grassed areas earlier and later each season, and we have drought impact on some native planting. New pests and diseases are also noted as thriving in the changing conditions and are likely to impact on historic fabric. Masonry bees, wood boring insects and textile eating moths all enjoy raised temperatures and changing humidity and are likely to become more widespread in Scotland.

Getting the work done - Working practices/materials

The working season for maintaining and repairing much of the historic environment is significantly affected by the weather. Simply put, digging, pointing masonry, repairing roofs and painting all require relatively calm weather, and preferably little or no rain.

The changes we seem to be seeing to the seasons are affecting our own work already, with high winds, heavy rain and fluctuating temperatures changing the timing of our work programmes and some of our working practices. I've already mentioned the extended growing season that makes our grasscutting more frequent. Summer storms have displaced our normally busy site time, but the reduced number of frosty days and the mild winter weather we have seen, have allowed us to continue lime pointing later in the year. At the moment the biggest issue for us is the less predictable nature of the seasons. Where once we knew what to expect in summer or winter we are now seeing sudden and unfamiliar changes which we have to accommodate. Using rope access for a quick hit maintenance solution based on daily conditions is proving more practical in some cases than a large scaffolding that might not be safe to be used for long periods due to high winds. Large work programmes are certainly becoming more challenging. These will all be issues that impact on the wider repair and maintenance sectors.

We are also having to consider how materials and methods might perform in these changed and changing conditions. For the properties in care we perhaps have a longer term view than some. We are often looking after structures which are not complete and are already challenged, but regular maintenance and monitoring ensure we keep on top of our responsibilities. We are monitoring levels of maintenance at our own sites and anticipate that some materials, such as building stone, slates and pointing may decay more rapidly in a changed climate. By how much is not easy to model but, as an Agency we have been involved in partnering recent studies to forecast the levels of repair to historic structures and the consequent demand for both materials and skills.

"Food miles" are now a familiar concept, "material miles" may also become a consideration in relation to tackling climate change.

Challenging solutions

For the properties in care we have always had to look at imaginative solutions some of which can inform other projects to prepare for the impacts of climate change. We already use turf as a weathering surface for open walltops and have very recently installed a "green" roof of sedum over part of Skara Brae. At Smailholm Tower we have an experimental roof comparing various vegetation surfaces in reducing water penetration and absorbing runoff.

Conservation is described as the "management of change" and as well as the challenges in dealing with the practical management of change for the wider impacts of climate change, it is the more immediate response to reducing carbon emissions where Historic Scotland has an important role.

Air conditioning, energy efficient replacement windows, local micro generators, wind farms and the replacement of older buildings with new, are among the issues where pressures on the historic environment are already most noticeable. They are also seen as the solution to reduce carbon footprints by a wide cross-section of society, principally concerned with reducing fuel consumption and showered with information about new technologies.

A better understanding of the wider picture which balances the issues of carbon footprints with sustainability and the historic environment, is needed to change public perceptions, and to see a more harmonious balance of new and old technologies.

Demonstrating the benefits of traditional technologies such as:

• "breathable" construction and natural ventilation,
• the benefits of embodied energy of traditional buildings vs demolition and replacement,
• their energy performance in comparison to new technologies,
• and the sustainability of much of the work around conservation of historic structures

all need wider dissemination and Historic Scotland is working with partners across a number of fronts to get these messages more widely understood, preparing monitoring information, research case studies, policy and guidance.

The historic environment can offer help in answering some of the issues raised by climate change, it has been around a long time and in some cases has already faced and survived several climate changes.

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