March 2013Issue 37

Environment

Ecosystem-based Adaptation

Science for Environment Policy

THEMATIC ISSUE:

ContentsEcosystem-based Adaptation - a powerful ally 3Editorial from guest editor Pam Berry

Salt marshes protect shorelines by reducing waves and erosion 5 Salt marshes stabilise shorelines and protect them from incoming waves, finds a recent study.

Coastal wetlands can protect against rising sea levels and increasing storms 6 Coastal wetlands reduce erosion, property damage and human deaths in the face of climate change impacts, research concludes.

‘Building with Nature’ increases resilience to climate change 7 A new coastal protection scheme in the Netherlands reduces ecosystem damage whilst offering resilience against flooding.

New guidelines to help implement ecosystem-based adaptation on islands 8 A new study examines current adaptation measures in tropical Oceania and identifies guidelines for implementing resilient adaptation for vulnerable island nations.

Ecosystem-based adaptation in the Caribbean: strengths and weaknesses 9 The importance of integrating local and external knowledge is highlighted in a new study examining climate change adaptation measures in the Caribbean.

Even small urban green spaces can help tackle the heat island effect 10Green spaces in cities can have a cooling influence which helps reduce the ‘urban heat island effect’, study finds.

A straight forward approach to assessing urban ecosystem services 11 New research trials a streamlined method for assessing ecosystem services in four European cities.

Land use can affect fresh water supplies 12 Supplies of fresh water depend not only on rainfall, but also on the land use in the river catchment.

Forest management for climate change adaptation must fit the context 13 Converting forests from deciduous to pine trees could help water storage in extreme wet conditions, but may be unsuitable in droughts, new study finds.

Ecosystem-based adaptation provides promising approach 14A new analysis highlights the advantages of soft ecosystem-based climate change adaptation over hard infrastructure approaches.

Call for integration of ecosystem-based adaptation into policy 15 There is good evidence for the effectiveness and cost-efficiency of ecosystem-based adaptation and its adoption should be encouraged, concludes a recent review.

Related articles 16A selection of recent articles from the Science for Environment Policy News Alert.

Science for Environment PolicyEcosystem-based Adaptation

This Thematic Issue is written and edited by the Science Communication Unit, University of the West of England (UWE), BristolEmail: sfep.editorial@uwe.ac.uk

The contents and views included in Science for Environment Policy are based on independent research and do not necessarily reflect the position of the European Commission.

Keep up-to-date

Subscribe to Science for Environment Policy’s weekly News Alert by emailing: sfep@uwe.ac.uk

Or sign up online at: http://ec.europa.eu/science-environment-policy

About Science for Environment Policy

Science for Environment Policy is a free news and information service published by the European Commission’s Directorate-General Environment, which provides the latest environmental policy-relevant research findings.

Science for Environment Policy publishes a weekly News Alert which is delivered by email to subscribers and provides accessible summaries of key scientific studies.

Thematic Issues are special editions of the News Alert which focus on a key policy area.

http://ec.europa.eu/science-environment-policy

EdITorIAl

Ecosystem-based Adaptation: a powerful ally

The impacts of climate change, from rising sea levels to increasing storm frequency and devastating droughts, are already affecting millions of people around the world. As a result there is an urgent need for robust and effective strategies which allow society and ecosystems to adapt to a changing world. Ecosystem-based adaptation (EbA), by employing ecosystem-based approaches and making use of green infrastructure, harnesses the adaptive forces of nature and provides one of the most widely applicable, economically viable and effective tools to combat the impacts of climate change. The low-cost, flexible approaches of EbA can also provide multiple other benefits, such as poverty alleviation and sustainable development.

There is growing recognition of the role ecosystems can play in helping people adapt to climate change. The concepts of EbA, working with nature, building with nature and green infrastructure1, while having different scopes, follow the same rationale: healthy ecosystems and the multiple services they provide are part of our life insurance and are essential in any strategy for avoiding dangerous climate change. Natura 20002, which ensures a carefully planned network of biodiversity-rich areas, is an essential pillar of green infrastructure that can also enhance resilience to natural disasters, such as floods, landslides or storm surges. This natural capital is now becoming even more valuable in the face of challenges that climate change presents.

This Thematic Issue from Science for Environment Policy brings together the latest research on EbA, providing evidence for the effectiveness of this approach and highlighting successful case studies.

Coastal areas are particularly at risk from climate change’s impacts. Over a third of the global population live in coastal settlements and the rising sea levels and increased storm frequencies already observed threaten not only property and jobs, but also human lives. Past strategies to alleviate the risks of flooding and storm damage have focused on ‘hard’ engineering approaches, such as dams or storm barriers. However, there is growing evidence that EbA will provide more flexible alternative options, vital to providing resilience under changing conditions.

The articles ‘Salt marshes protect shorelines by reducing waves and erosion’ and ‘Coastal wetlands can protect against rising sea levels and increasing storms’ both combine the results of multiple studies

revealing that coastal ecosystems, such as mangroves and marshes, are highly effective in protecting the coast against the impacts of climate change. Together they demonstrate that coastal vegetation can be used for adaptation to rising sea levels and increased storms via multiple positive effects, such as sediment trapping and reduction in erosion, storm surge, and wave height. A case study in India suggests that these beneficial effects are likely to have reduced the number of human deaths caused by cyclone impacts.

The benefits of ‘soft’, ecosystem-based approaches to reducing coastal erosion due to climate change are also highlighted by the article ‘‘Building with Nature’ increases resilience to climate change’, which focuses on an innovative approach taken in the Netherlands, the ‘Delfland Sand Engine’. For this project, many millions of tonnes of sand were deposited on the Dutch coastline and wind and tides are now being allowed to redistribute the sand naturally. The long life-cycle of this project suggests it will be resilient to slow, long-term changes, and will provide the added benefit of undisturbed habitat for wildlife.

Threats from sea-level rise and increased storm severity are of particular concern for island populations where many settlements are coastal, and local livelihoods may depend on ecosystems, such as reefs or fisheries. Furthermore, small island nations are often unable to afford extensive hard infrastructure for defence against flooding or severe storms and therefore low-cost adaptation methods, such as EbA, are very useful. The articles ‘New guidelines to help implement ecosystem-based adaptation on islands’ and ‘Ecosystem-based adaptation in the Caribbean: strengths and weaknesses’ highlight the

3

4

potential value of EbA to island nations in both tropical Oceania and the Caribbean. However, they also find that integration of local and external knowledge, a key factor for effective implementation of EbA, is often neglected. Both studies strongly recommend the full involvement of local communities in planning adaptation measures.

EbA is not restricted to the protection and use of ‘pristine’ or ‘natural’ ecosystems, and it is important to recognise that green infrastructure in urban areas can also provide important services which help adaptation to climate change. ‘Even small urban green spaces can help tackle the urban heat island effect’ examines a case study in Portugal and shows how a small neighbourhood garden can provide significant cooling to the surrounding area, helping offset the effects of the increased frequency and severity of urban heat waves expected under climate change.

‘A straightforward approach to assessing urban ecosystem services’ also focuses on the value of urban green spaces, and provides a tool to help city planners enhance ecosystem services and aid development of effective adaptation strategies.

Ecosystem services, such as supplies of clean water, are becoming increasingly important under climate change and EbA strategies can contribute to their protection and maintenance. The articles ‘Land use can affect fresh water supplies’ and ‘Forest management for climate change adaptation must fit the context’ both explore how the negative effects of climate change can be counteracted through land management. These studies

both demonstrate how various land uses store different amounts of water which can affect local water supplies.

The final articles in this issue ‘Ecosystem-based adaptation is promising’ and ‘Call for integration of ecosystem-based adaptation into policy’ provide overviews of the effectiveness and cost-efficiency of EbA. Along with the articles highlighted above, these reviews show that evidence is building to show that EbA is a very useful, cost-effective tool in facing the challenges of climate change. Both reviews examine the economics of EbA implementation and stress that although EbA does require investment, its financial benefits can outweigh the costs many times over.

A particular strength of EbA, evident in many of the articles in this issue, is its multiple benefits over and above adaptation to the immediate effects of climate change. For example, it can also benefit biodiversity protection, sustainable development, poverty alleviation and carbon storage. EbA through restoration and conservation of coastal wetlands and mangroves, for instance, not only reduces erosion, but can also store carbon, enhance biodiversity and replenish fish stocks, which in turn may safeguard local livelihoods based on industries such as wildlife tourism and fisheries.

The integration of EbA into policy is gaining increasing momentum and cross-sector co-operation, promotion of good practice and stakeholder involvement will ensure its effective implementation. Policymakers now have the valuable opportunity to act to ensure that this powerful approach is used to its full potential.

Dr Pam Berry Environmental Change Institute, University of Oxford

1 http://ec.europa.eu/environment/nature/ecosystems/index_en.htm2 http://ec.europa.eu/environment/nature/natura2000/index_en.htm

5

Salt marshes protect shorelines by reducing waves and erosion

Conserving salt marshes helps protect our coasts, according to research which shows that they stabilise shorelines and protect them from damage by incoming waves. Their benefits are particularly significant in light of the destruction caused by storms and flooding, which are likely to increase under climate change.

Despite their protective benefits, salt marshes are frequently destroyed and replaced by manmade coastal defences, such as sea walls. After Hurricane Katrina hit the US in 2005, it was suggested that conserving salt marshes could have helped reduce the widespread damage that occurred. In the face of increasing concerns about storms, flooding and sea level rise under climate change, it has become important to fully understand the protective role of salt marshes.

In 2011, researchers carried out a review of studies on marshes and coastal protection, focusing their search on the shore-stabilising and wave and flood-reducing effects of marshes. By collating and collectively analysing the results of these studies, the authors found that marshes were consistently and significantly effective in reducing waves and erosion, and in stabilising and growing shorelines.

From 33 shore stabilisation studies that compared the effects of vegetated and unvegetated areas, the majority (58%) found that vegetated marshlands had positive effects. The degree of protection offered depended on the types, density and heights of plants present in marshland. Plants seemed to protect coastal areas by capturing sediment above ground and growing roots below ground to raise the level of the stable surface.

From 14 studies on wave impacts, the researchers identified several factors that were important, for example, marsh width, and vegetation density and height were key to reducing waves’ impacts. In particular, four studies found that wider marshes had significant positive effects in protecting shorelines from waves. The results were drawn from a range of settings, covering Europe, North America and China, and small to moderate waves.

The researchers also identified 121 studies related to flood protection, but none of these provided quantitative data on the amount of floodwater stored in coastal marshes or the peak level of flood reduction. This gap in scientific understanding needs to be urgently addressed, as most of the deaths caused by hurricanes and storms are related to flooding. However, the studies did reveal a general trend for natural marshland to drain more quickly than altered marshland.

According to the researchers, their review provides support for comprehensive approaches to coastal protection and climate change adaptation that incorporate natural features, such as marshes. There are already ongoing projects in the Netherlands and UK to realign coastal defences to allow for areas of marshland. More computer modelling and field studies to quantify the risk reduction benefits of marshes will allow a better understanding of when and where salt marshes can be incorporated into coastal protection planning, the researchers say.

Contact: mcshepard@tnc.orgTheme(s): Natural hazards, Marine ecosystems, Climate change and energy

“In the face of increasing concerns about storms, flooding and sea level rise under climate change, it has become important to fully understand the protective role of salt marshes.”

E C O S y S T E M - b A S E D A D A P T A T I O N

Source: Shepard, C.C., Crain, C.M. & Beck, M.W. (2011). The protective role of coastal marshes: a systematic review and meta-analysis. PloS One, 6(11): e27374. DOI: 10.1371/journal.pone.0027374. This study is free to view at: www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0027374

6

Coastal wetlands can protect against rising sea levels and increasing storms

Coastal wetlands can substantially reduce erosion, property damage and human deaths in the face of rising sea levels and severe storms, recent research concludes. Understanding whether wetlands can provide effective coastal protection is essential to developing effective climate change adaptation strategies.

Over a third of the global population live in coastal areas, and the number of people at risk of flooding is predicted to increase by a factor of five in this century. Although wetland vegetation has been widely assumed to provide coastal protection, some small-scale studies have suggested that other coastal features, such as the structure of the shoreline’s landscape, are more important protective factors, not the ecosystems themselves.

The researchers gathered information from a range of previous studies to gain a better understanding of wetland vegetation’s protective role. Together, the results demonstrate that wetland vegetation is able to protect against coastal erosion both directly, as plants slow water speed and reduce turbulence, and indirectly, by trapping sediment and enriching soil with organic material.

For example, an experiment using a wave tank showed that erosion rates were between 33 and 82% lower for sediments with vegetation, versus those without. A much larger scale study, using satellite images of Thailand between 1967 and 1998, found that areas with mangrove forests had substantially lower erosion rates than those without. Importantly, this study also demonstrated that coasts where mangroves had been removed through deforestation eroded just as quickly as those where they had never been present. This suggests that it is the vegetation itself, not merely associated shoreline structure as suggested, that provides protection.

There is also evidence that coastal wetland ecosystems are able to protect, to some degree, against the rise in water levels associated with a storm. Observations of storm surges have shown reductions in water height of between 4.4 and 15.8 centimetres per kilometre of wetland covered. Research has also found that vegetation can substantially reduce the strength of waves as they hit the land.

Results from a study in India indicate that, without mangroves, a cyclone that struck in 1999 would have caused an additional 1.72 deaths per coastal village. The prevention of economic damage is also significant; the loss of 1 square kilometre of mangrove forest in Thailand was estimated to cost an average of US$187,898 (€140,924) per square kilometre in subsequent storm damage.

Finally, the researchers discuss whether coastal ecosystems can continue to provide such ecosystem services in the future. Predictions of sea level rise, which could exceed 9 millimetres per year in this century, are worrying. However, coastal ecosystem resilience may be higher than expected due to increased trapping of sediment as water levels rise, and the boosted growth rates of underwater plants. The researchers also suggest that manmade infrastructure, such as artificial reefs, could also be used to help improve conditions for wetland ecosystems and ensure they can continue to protect the world’s coasts.

Contact: kgedan@umd.eduTheme(s): Climate change and energy, Marine ecosystems, Natural hazards

“Results from a study in India indicate that, without mangroves, a cyclone that struck in 1999 would have caused an additional 1.72 deaths per coastal village.”

Source: Gedan, K. B., Kirwan, M. L., Wolanski, E. et al. (2011). The present and future role of coastal wetland vegetation in protecting shorelines: answering recent challenges to the paradigm. Climatic Change. 106: 7–29. DOI: 10.1007/s10584-010-0003-7.

E C O S y S T E M - b A S E D A D A P T A T I O N

7

‘building with Nature’ increases resilience to climate change

Rising sea levels and increased storms as a result of climate change are threatening coastal settlements across the globe. The risk of flooding in coastal areas has generally been met with ‘hard’ engineering approaches, such as dams or storm barriers. However, the wisdom of such approaches is being increasingly challenged; critics highlight that hard engineering solutions often disrupt natural water and sediment flows and do not adapt easily to changing conditions.

In this study, researchers examined a case study in Holland, a densely populated region of the Netherlands with around 8 million inhabitants living in areas of high flood risk, often below sea level. These settlements are protected from flooding by coastal dunes and beaches, which also provide other vital ecosystem services, such as filtering drinking water and providing habitats for wildlife.

Coastal protection strategies in the area have changed over time. Initially, hard engineering techniques, such as reinforcements and dams, were used. However, in 1990, policy shifted and adding volumes of sand to eroded coastal regions became the main form of defence. This ‘soft’ engineering approach has less impact on sediment flow, but the need to add more sand every year buries organisms on the seabed and destroys some habitats.

In 2011, a new pilot project, the Delfland Sand Engine, was completed. Under this strategy, much larger amounts of sand are added (20 million m3 rather than 1 million m3, as previously), extending 2 km along the coast. This large mound of sand is not maintained or added to, ensuring an undisturbed environment for wildlife and the natural redistribution of sand along the coast by tides and wind.

The researchers evaluated this coastal protection strategy using a conceptual framework called ‘Building with Nature’ that consists of three main elements: resilience of a system and its ability to withstand disturbance; social learning by taking into account different stakeholder views; and ecosystem services provided, such as coastal defence and drinking water filtration. This approach also explicitly includes humans as part of the natural system.

The researchers conclude that, although it is too early to present a final assessment, the Delfland Sand Engine represents an important shift in climate change adaptation. The site has a cycle of 20 years or more before the sand will be naturally depleted, suggesting it will be more resilient to slow, long-term changes. Input from many different stakeholders, not only coastal engineers, has been considered, enhancing public acceptance. Finally, allowing the system to develop naturally has meant that habitats for wildlife are undisturbed.

Contact: erik.vanslobbe@wur.nl Theme(s): Climate change and energy, Marine ecosystems, Natural hazards

“The risk of flooding in coastal areas has generally been met with ‘hard’ engineering approaches, such as dams or storm barriers. However, the wisdom of such approaches is being increasingly challenged.”

Source: van Slobbe, E., de Vriend, H. J., Aarninkhof, S., et al. (2013). Building with Nature: in search of resilient storm surge protection strategies. Natural Hazards. 65:947–966. DOI: 10.1007/s11069-012-0342-y. This study is free to view at: www.springerlink.com/content/j7082p815n577622/?MUD=MP

E C O S y S T E M - b A S E D A D A P T A T I O N

New ecosystem-based solutions which provide flexible resilience to coastal flooding, rather than rigid defences, are needed in the face of global environmental change. A recent study examines a new coastal protection scheme in the Netherlands which reduces ecosystem damage whilst offering resilient defence against flooding. Using this case study, the researchers present a framework for evaluating climate change adaptation measures called ‘Building with Nature’.

8

New guidelines to help implement ecosystem-based adaptation on islands

Climate change is a particular threat to island nations and effective adaptation is vital. A new analysis examines current adaptation measures in tropical Oceania and identifies guidelines for implementing resilient, ecosystem-based adaptation (EbA). Among its recommendations, local communities should be fully involved in planning adaptation measures.

EbA, the protection and restoration of ecosystems for provision of key ecosystem services, will be especially valuable in helping island populations face the challenges of climate change. Small islands are particularly at risk as sea level rise may flood coastal communities and ecosystems damaged by flooding can deplete local resources and affect livelihoods. The majority of the world’s small island nations are found in tropical Oceania, which includes Melanesia, Polynesia and Micronesia. Rural poverty is high across the region and many people are dependent on coastal ecosystems for their livelihoods and food security.

This research demonstrates that many of the current responses to climate change could be improved by moving towards EbA. For example, droughts have already led to water shortages in some areas. Current measures to cope with such situations include water rationing and bathing in streams, which may result in poor hygiene and lead to health problems. A sustainable alternative would be to restore and protect vegetation surrounding water catchments to prevent evaporation and loss of water.

Another example is the flooding of coastal settlements following storm surges, which has resulted in new buildings being constructed inland. This is an unsustainable solution because there is a shortage of resources and available land. An ecosystem-based approach to this problem may include restoring mangrove wetlands which help protect against coastal erosion and sea level rise. Having identified some changes that could help island nations adapt to climate change, the researchers developed guidelines for their implementation. They strongly recommend that the local community must be fully involved for any adaptation measures to be effective. Initial steps should include raising community awareness and ensuring stakeholder participation. A successful example of this is workshops to build three dimensional models of the local region, which has been used in Fiji, Papua New Guinea and the Solomon Islands. The local community build the models themselves, overlaying them with maps of resources or human pressures. This process has been found to facilitate group discussion and help provide a sense of ‘ownership’ of adaptation measures.

Involving the local people in this way also aids community-based management, another important aspect to effective adaptation. For example, across Oceania and particularly within the Locally Managed Marine Area Network, local communities have formed natural resource management committees to design and implement management strategies that best fit their local context. As global climate change affects local ecosystems and resources, the committees are able to quickly respond by adapting management practices to maintain important ecosystem services.

The researchers conclude that ecosystem-based approaches are an important tool in adapting to climate change and will require careful integration of national policy and planning, local communities, and the conservation and natural resource management sectors.

Contact: kgedan@umd.eduTheme(s): Climate change and energy, Environmental information services, Natural hazards

“Small islands are particularly at risk as sea level rise may flood coastal communities and ecosystems damaged by flooding can deplete local resources and affect livelihoods.”

Source: Grantham, H. S., Mcleod, E., Brooks, A., Jupiter, S. D. et al. (2011). Ecosystem based adaptation in marine ecosystems of tropical Oceania in response to climate change. Pacific Conservation Biology. 17(3): 241–258.

E C O S y S T E M - b A S E D A D A P T A T I O N

9

Ecosystem-based adaptation in the Caribbean: strengths and weaknesses

Many small island states in the Caribbean rely on the services ecosystems provide. For example, the value of coral reefs in the region has been estimated at between US$3.1 and 4.6 billion (€2.3-3.4 billion) for services such as fisheries, tourism and coastal protection. Preserving such ecosystems to help adapt to climate change is of particular importance for islands where local livelihoods may be threatened.

In this study, researchers show that at the regional level, although there is some coordination of ecosystem-based adaptation (EbA) between countries, there are not yet any coherent strategies or policies that have translated into ecosystem-based management on the ground. They also find that most attention at this scale is focused on coastal management, neglecting other ecosystems important to climate change adaptation, such as forested water catchments.

At the national level, the situation is improved, partly with support from other countries. For example, the EU has been working with the Planning Institute of Jamaica to help implement more ecosystem-focused approaches to watershed rehabilitation and coastal management. However, such projects do not specifically mention EbA and do not seek to incorporate local communities and knowledge.

Finally, at small, local scales some measures taken do show progress towards realised, ecosystem-based approaches, with acknowledgement of the need to include local knowledge. For example, local partners in Haiti and the charity BirdLife International have worked together to restore and area of degraded forest, stabilising slopes against landslides and ensuring water supply to local communities.

The researchers conclude that although some progress has been made in the Caribbean, improvements are needed. In particular, local knowledge has been largely ignored in projects and planning processes at the national and regional scales. This is an important omission because, as well as providing useful insight, incorporating local viewpoints can facilitate community-based management of adaptation measures, which has been shown to improve their success. Although the researchers acknowledge that local, traditional approaches must not be ‘romanticised’, they stress that their value should not be discounted.

Researchers recommend identifying ‘local champions’ which could help raise awareness and enthusiasm in local communities. They also caution that although the term ‘ecosystem-based adaptation’ is relatively new, there is a wealth of past research and data, especially within the conservation sector, which should be used in its implementation. Finally, they highlight the need for continued monitoring and evaluation.

Contact: tiina.kurvits@grida.noTheme(s): Climate change and energy, Environmental information services, Natural hazards

“… as well as providing useful insight, incorporating local viewpoints can facilitate community-based management of adaptation measures, which has been shown to improve their success.”

Source: Mercer, J., Kelman, I., Alfthan, B. et al. (2012). Ecosystem-Based Adaptation to Climate Change in Caribbean Small Island Developing States: Integrating Local and External Knowledge. Sustainability. 4: 1908-1932. DOI: 10.3390/su4081908. This study is free to view at: www.mdpi.com/2071-1050/4/8/1908

E C O S y S T E M - b A S E D A D A P T A T I O N

Protecting ecosystems and the services they provide is increasingly thought to be a sustainable and effective approach to help society adapt to climate change. Islands states, at risk from a variety of different threats, including sea level rise, changes in rainfall patterns and ocean acidification, have been among the first to trial this approach. A new study examines measures taken in the Caribbean and highlights the importance of integrating local and external knowledge.

10

Even small urban green spaces can help tackle the heat island effect

Green spaces in cities can have a cooling influence which helps reduce the ‘urban heat island effect’. New research from Portugal has demonstrated that even a small community garden can provide a significant cooling impact that can help efforts to adapt to climate change.

Climate change is expected to cause hotter and drier summers in many locations, increasing the ‘urban heat island effect’ where built-up areas become hotter than their rural surroundings. Studies of urban green spaces of a few hectares or more frequently demonstrate cooling effects. This study set out to explore whether smaller green spaces might also provide notable cooling benefits. A case study was undertaken of a neighbourhood garden in Lisbon of only 0.24 hectares.

Garden Teofilo de Braga is situated in central Lisbon, a densely populated area. The garden is mainly used by the elderly and young, age groups that are particularly vulnerable to heat stress. The park is most used during the afternoon when the sun is high. In summer, a variety of trees provide canopy coverage of 96.5%.

Data were recorded both within and beyond the garden over six hot summer days, three of which saw temperatures exceed 32oC, the threshold above which mortalities have been observed to increase. Both maximum and average temperatures were recorded, and an index assessing the impact of temperature on human biology, the ‘Physiologically Equivalent Temperature’, which takes into account the biological effect of air temperature, long and short wave radiation, humidity, wind speed, and even people’s clothing.

Temperatures within the garden were often significantly cooler than nearby locations. The cooling effect was most marked on the hottest day, in which the garden’s highest temperature was a 6.9oC cooler than surrounding locations. Mean temperatures and the impact on human physiology were also significantly lower within and close to the garden.

The study demonstrated that small green spaces in cities can have a valuable cooling effect that may extend for some distance beyond the park – 200 metres in this study, and several hundred metres in another study of a 3 hectare garden in Japan.

However, factors other than vegetation shading were recognised as important. The dry Mediterranean climate of Lisbon was thought to cause more cooling from evaporation than comparable studies of gardens in more humid climates. Buildings and design of the surrounding areas, the amount of shade and wind speeds, for example, can also affect temperatures both within and beyond green spaces.

In this study, a street with north-south orientation (and therefore receiving minimal sunshine) and high shading by buildings and trees showed similar temperatures to those within the garden. Such findings illustrate the value of using local data to better appreciate the potential cooling impacts in a given climate and urban form, and the factors which might encourage cooling.

Contact: sisoliveira@hotmail.comTheme(s): Climate change and energy, Urban environment

“The cooling effect was most marked on the hottest day, on which the garden’s highest temperature was a 6.9°C cooler than surrounding locations.”

Source: Oliveira, S., Andrade, H., and Vaz, T. (2011). The cooling effect of green spaces as a contribution to the mitigation of urban heat: a case study in Lisbon. Building and Environment. 46: 2186-2194. DOI: 10.1016/j.buildenv.2011.04.034..

E C O S y S T E M - b A S E D A D A P T A T I O N

11

A straightforward approach to assessing urban ecosystem services

In an increasingly human-dominated and urban world, there is a need to understand how cities can maintain and restore the ecosystem services on which people depend, especially in the face of climate change. This study, conducted by members of the EU BiodivERsA network1, sought to develop a practical method for quantifying the ecosystem services of urban locations that would be of use to city planners.

It first examined a range of previous studies to identify sources of data which might simplify ecosystem service assessment. For example, the area of ‘impervious’ land, which cannot absorb water, such as concrete or road surface, was used as a basic indicator for all ecosystem services. In addition, ‘regulatory’ ecosystem services were represented by factors which helped cool the city, such as rivers, or provide carbon sequestration, such parks and gardens. The study also considered ‘recreational’ ecosystem services by assessing areas of forest and lakes.

Four major EU cities were assessed using this method: Berlin, Salzburg, Stockholm, and the Helsinki Metropolitan Area. Data were collected within the urban centres and at regular intervals up to 30km into the outskirts of the cities.

Each city showed a different pattern of ecosystem service provision, making it difficult to show a direct link between urban design and services provided, for example, some city centres were more impervious to water than the outer areas, but in others, this was reversed. Some city centres performed highly – central Salzburg and Helsinki showed good water permeability and climate regulation due to abundant green spaces. However, the study concluded that it was difficult to locate ‘optimal sites’ in which all indicators scored highly, although forested areas were identified as ecosystem service ‘hotspots’ due to their ability to sequester carbon and cool the surrounding air.

The researchers say their work helps planners simplify the complexity of monitoring ecosystem services through the use of manageable data. A deliberately limited subset of ecosystem services is considered (for instance, excluding biodiversity), however, they suggest that other data could be added to enhance their approach, for example, climate cooling information could be combined with data on the number of deaths as a result of high temperatures.

The approach provides planners with a way to quantify the potentially complex field of ecosystem services across urban areas. The data can help planners in a variety of ways, by providing information to assess development proposals, helping develop policies to reduce environmental inequalities, and strengthening integration of local and regional planning.

Contact: dagmar.haase@ufz.deTheme(s): Climate change and energy, Sustainable development and policy assessment, Urban environment

“The approach provides planners with a way to quantify the potentially complex field of ecosystem services across urban areas.”

Source: Larondelle, N. & Haase, D. (2013). Urban ecosystem services assessment along a rural–urban gradient: A cross-analysis of European cities. Ecological Indicators. 29: 179–190. DOI: 10.1016/j.ecolind.2012.12.

E C O S y S T E M - b A S E D A D A P T A T I O N

Ecosystem-based adaptation to climate change relies on the services provided by nature; new research has now demonstrated the wide potential of urban ecosystem services to aid local adaptation efforts. This study developed and trialled a streamlined method for assessing ecosystem services, such as temperature reduction and carbon sequestration, in four European cities, providing a valuable tool to help city planners enhance ecosystem services.

1. BiodivERsA is supported by the European Commission under the Seventh Framework Programme. See: www.biodiversa.org. This study was conducted under URBES (Urban Biodiversity and Ecosystem Services) project of BiodivERsA. See: www.biodiversa.org/121

12

Land use can affect fresh water supplies

New research has shown that supplies of fresh water provided by rivers depend not only on rainfall, but also on the land use within the river catchment. In the Spanish Basque Country, grasslands were found to supply the greatest amount of river water, followed by native woodlands, with exotic woodland plantations providing the least. The researchers also call for more comprehensive analyses of ecosystem services, including carbon sequestration and biodiversity, to inform land use policy.

Ecosystems can provide vital services, such as fresh drinking water supply, which help humans adapt to climate change. Experiences in the Basque Country illustrate the need to better understand how land use decisions can influence water supply, since this is a highly populated and industrialised area with an increasing demand for water, vulnerable to increasing droughts under climate change.

This study aimed to explore how land use decisions affect the volumes of fresh water provided by rivers and streams in the Basque Country. Fifteen catchments were studied, with similar geology, topography (shape of the land’s surface) and climate. Over two years, rainfall was analysed and related to river flow levels in areas with the following land uses: grassland pastures, native woodland, and exotic (mainly pine) tree plantations.

The researchers defined the fresh water supplied by different land uses as ‘water productivity’, the monthly discharge of water by rivers, divided by the total rainfall received within the catchment. Therefore water productivity was higher when a greater proportion of rainfall reached rivers and streams. The study focused on this simple ratio of water provision, instead of considering how water productivity might relate to soil erosion rates or the steadiness of water supply over seasons. Exotic pine plantations were shown to yield the smallest flows of freshwater. This is likely to be because exotic trees, such as pines and eucalypts, have high water requirements, leading to the drying of soils and less rainfall reaching rivers. Native woodlands were also of low water productivity, though most of the native woods studied were recovering from previous usage as plantations and were therefore in the early, immature stages of woodland development. Traditional grazing pastures were the most water productive of the land uses.

The researchers criticise plantations as a land use, since they yield 50% less water than pastures over the course of a year. In addition to their low water yields, the researchers also drew attention to plantations’ limited biodiversity and declining economic value, and other studies which have shown decreased water quality resulting from clear-felling of plantations.

The study also draws attention to the value of quantifying water provision from local land usages when establishing water ‘Payment for Ecosystem Services’ schemes. Finally, it concludes that, in addition to measuring water productivity, land use policy should be informed by a comprehensive analysis of ecosystem services, including factors such as carbon sequestration and biodiversity.

Contact: eneko.garmendia@ehu.esTheme(s): Climate change and energy, Forests, Land use, Water

“Exotic pine plantations were shown to yield the smallest flows of freshwater.”

Source: Garmendia, E., Mariel, P., Tamayo, I. et al. (2012). Assessing the effect of alternative land uses in the provision of water resources: Evidence and policy implications from southern Europe. Land Use Policy. 29: 761-770. DOI: 10.1016/j.landusepol.2011.12.001.

E C O S y S T E M - b A S E D A D A P T A T I O N

13

Forest management for climate change adaptation must fit the context

Forests are valuable providers of ecosystem services related to water supply for humans and wildlife. However, climate change can directly alter the amount, type and timing of precipitation, such as rain and snow. It can also have indirect effects via changes in temperature and CO2 levels that can increase water use by plants and decrease the water flow into streams and rivers.

Some of the negative impacts of climate change can be counteracted through forest management. Changing tree species can change the amount of water released to the air from leaves (‘evapotranspiration’) and the amount of water trees catch from precipitation (‘interception’). Both these processes affect the amount of water stored in trees and therefore the amount that reaches waterways via the trees’ roots.

The study aimed to quantify the interaction between climate, forest management and stream flow by analysing 75 years of data from six watersheds in the US with changing management strategies. On two watersheds there had been a conversion from deciduous forest to evergreen plantation, whilst two other watersheds experienced continuous clearcutting where all or most trees were removed. Another watershed had experienced clearcutting and the growth of wood from stumps and roots (coppice), whilst on the final watershed woody vegetation had been removed and allowed to grow back naturally (old-field succession).

In the year following the management change, all watersheds experienced a significant increase in the level of stream flow, ranging from a 19% increase under old-field succession to 70% under clearcut and coppice.

In the majority of the watersheds, there was a noticeable impact of management. For example, under old-field succession and clear cutting strategies there was a shift to trees with high evapotranspiration rates that use more water in wet years and provide the soil with a greater water storage capacity, reducing stream flow. For old-field succession, the age of the returning forest could also be a factor, as fully-developed trees are likely to use more water. In the two cases where evergreen trees were planted, stream flow was reduced in both wet and dry years, which may be due to the greater interception of precipitation by these trees.

The results indicate that forest management can be used to help adapt to climate change, but potential trade-offs must be considered. For example, converting to dense pine forests could mitigate high flows and flood risk in wet years, but in the drier years this could exacerbate drought. As such, it is critical to assess the context to make the most appropriate choice of management and vegetation.

Contact: crford@usgcrp.govTheme(s): Climate change and energy, Forests, Water

“… forest management can be used to help adapt to climate change, but potential trade-offs must be considered.”

Source: Ford, C.R., Laseter, S.H., Swank, W.T. & Vose, J.M. (2011) Can forest management be used to sustain water-based ecosystem services in the face of climate change? Ecological Applications. 21(6): 2049-2067.

E C O S y S T E M - b A S E D A D A P T A T I O N

Forest management could help adaptation to climate change through its effects on water supply. A long-term US-based study has analysed the impact of forested land use changes on water flow into streams and rivers. It indicated that converting forests from deciduous to pine trees could help water storage in extreme wet conditions, but may be unsuitable in droughts. As such, it recommends tailoring management decisions to the context.

14

Ecosystem-based adaptation provides promising approach

The advantages of soft ecosystem-based climate change adaptation over hard infrastructure-based approaches are becoming increasingly recognised. A new analysis highlights these advantages and calls for more effort to improve our understanding of ecosystem-based adaptation’s (EbA) effectiveness.

The importance of adapting to climate change is an internationally recognised issue and this is reflected in the funds committed to it. However, although financial recognition is a huge step forwards, it is important to ensure the money is spent effectively and sustainably.

Adaptation to climate change can be categorised into two approaches. ‘Soft’ approaches focus on capacity building and information, such as early warning systems and educating at-risk communities. ‘Hard’ approaches use specific technologies and actions, such as sea walls or levees. EbA shares features from both and involves management, conservation and restoration activities to protect and enhance ecosystem services, for example, flood protection by wetlands.

The study outlines three ways in which EbA may complement or improve hard approaches. Firstly, it can increase overall capacity to cope with climate change. For example, on the Yangtze River in China, hard infrastructure of dams and dykes have been integrated with a seasonal opening of sluice gates to restore connections between the natural features of river, lakes and wetlands. This increases floodwater retention, water purification and agricultural opportunities.

Secondly, EbA may be more cost-effective than hard interventions. For example, in the Maldives, building sea walls costs about US$1.6-2.7 billion (€1.2-2.1 billion) compared to preservation of the natural reef, which has an initial set up cost of US$34 million (€26 million) and maintenance costs of US$47 million (€36 million) per year.

Lastly, in some cases, EbA may be the only possible option. For instance, in many small island states it is not possible to combat death of coral reefs with hard measures, so responses in the form of marine protected areas are the only foreseeable solution.

EbA has advantages over hard approaches in that it tends to provide multiple benefits in addition to climate change adaptation. For example, it may help conserve biodiversity, improve health and recreation, and provide economic opportunities in terms of tourism. In contrast, few hard interventions provide benefits beyond the specific adaptation function for which they were designed.

Compared to hard approaches, EbA also tends to be more flexible, which is valuable in the face of an uncertain climate in the future. For instance, levees protect coasts from a limited sea-level rise, but protective wetlands can migrate inland as sea levels increase, adapting to the new conditions. Furthermore, hard engineering interventions may need frequent and costly maintenance, whereas EbA is more likely to be self-managing or require low maintenance.

There appear to be several advantages of EbA, however, the researchers call for a firmer evidence-base to support and encourage its use. There is a need for better quantification of EbA’s benefits, the effects of climate change on ecosystems’ capacities and more detailed comparisons between EbA and other adaptation strategies. With more knowledge, these approaches can be better applied to provide smart solutions.

Contact: hpjones@ucsc.eduTheme(s): Climate change and energy, Biodiversity, Sustainable development and policy assessment

“EbA has advantages over hard approaches in that it tends to provide multiple benefits in addition to climate change adaptation.”

Source: Jones, H.P., Hole, D.G. & Zavaleta, E.S. (2012) Harnessing nature to help people adapt to climate change. Nature Climate Change. 2:504-509. DOI: 10.1038/NCLIMATE1463.

E C O S y S T E M - b A S E D A D A P T A T I O N

15

Call for integration of ecosystem-based adaptation into policy

Adaptation is needed to deal with rising sea levels, droughts and floods brought by climate change. However, there have been increasing calls to move away from adaptation measures based on manmade infrastructure, such as sea walls, to approaches that involve more natural solutions.

Preserving ecosystems can help meet adaptation needs, such as disaster risk reduction, food security, sustainable water management and livelihood diversification. This new analysis highlights examples including healthy mangrove forests and coastal marshes that can reduce the impacts of storm surges, and connecting grasslands and forests that can enable wildlife to move to new habitats under a changing climate. EbA can also generate other benefits, such as carbon sequestration and social benefits, improved access to green spaces or better air quality.

The study also assesses the economic benefits of EbA. The Economics of Ecosystems and Biodiversity1 studies indicate that an annual global investment of US$45 billion (€33.8 billion) into ecosystem protection could deliver an estimated US$5 trillion (€3.8 trillion) a year in benefits. At a more specific level, it is estimated that a US$20 billion (€15 billion) investment in reducing deforestation could reduce greenhouse gas emissions by 10% while securing livelihoods and reducing poverty in tropical countries.

In the Maldives, where around 80% of the islands are only one metre above sea level, the use of marine protected areas to conserve reefs would help protect against the impact of tropical storms. It is estimated that this would cost US$34 million (€25.6 million) initially and US$47 million (€35.3 million) to maintain, but would generate US$10 billion (€7.5 billion) per year in benefits from protecting the islands and their valuable tourism and fishery industries. This means the benefits outweigh maintenance costs more than 200 times. For EbA to be fully effective, it must be integrated into decision-making. The United Nations Environment Programme (UNEP) addresses climate change, among other issues, through its EbA programme, which has three main components. Firstly, it supports countries to assess impact and vulnerability. This involves analysing ecosystem services for adaptation potential and economic value to allow decision-makers to design and implement EbA policies. Secondly, it provides support for implementing EbA through technological development and pilot projects, especially in developing countries.

Lastly, UNEP’s programme helps integrate EbA into national adaptation plans that establish organisations to mobilise stakeholders. An example of such an organisation at the national level is the US Task Force for Climate Change Adaptation that supports locally-focused, participatory, ecosystem-based approaches to planning and decision-making.

However, despite the evidence in favour of EbA, and increasing references to it in policy documents, it has not been used to its full potential. The researchers recommend more co-ordinated integration of this powerful approach into policy at local, national and international levels.

Contact: richard.munang@unep.orgTheme(s): Climate change and energy, Sustainable development and policy assessment

“For EbA to be fully effective, it must be integrated into decision-making.”

Source: Munang, R., Thiaw, I., Alverson, K., Mumba, M. et al. (2013) Climate change and Ecosystem-based Adaptation: a new pragmatic approach to buffering climate change impacts. Current Opinion in Environmental Sustainability 5:1-5. DOI: 10.1016/j.cosust.2012.12.001.

E C O S y S T E M - b A S E D A D A P T A T I O N

A new review of ecosystem-based approaches to climate change adaptation has described the multi-functional benefits of integrating such measures into policy. It concludes that there is good evidence for the effectiveness and cost-efficiency of ecosystem-based adaptation (EbA), and that its adoption by policymakers and stakeholders should be encouraged.

1. See: www.teebweb.org

A selection of articles relevant to Ecosystem-based Adaptation from Science for Environment Policy’s News Alert. Informing climate change adaptation in forestry management (26 July 2012)Adapting to climate change is essential to the sustainable management of forestry but it needs to be grounded in current scientific knowledge. A recent US study has brought together scientific experts and forestry managers to ascertain some general adaptation strategies for the future.

Promoting Natural Water Retention - An Ecosystem Approach (May 2012)By a combination of human activities, the European environment has been progressively dehydrated through overexploitation of its water resources. Climate change is likely to place even greater pressures on these resources, which provide essential ecosystem services to communities throughout Europe, and also lead to an increased risk of extreme events, such as droughts and flooding.

Building urban resilience to climate change (2 August 2012)Long-term urban planning is needed to adapt the urban environment and make it more resilient to climate change, according to a new European Environment Agency report that aims to support urban policy development and decision making.

Plant biodiversity boosts ecosystem services in drylands (15 March 2012) Plant biodiversity is crucial to the functioning of natural ecosystems in drylands across the world, according to recent research. Preserving plant diversity will be particularly important for maintaining the quantity and quality of services provided by ecosystems found in drylands that are vulnerable to the adverse effects of climate change and desertification

A new approach to studying climate change adaptation (21 October 2010) Researchers have applied a new approach to investigate the possible options for governmental intervention to support adaptation to climate change. Using this approach they identified three fields of adaptation policy with future potential: generation and spreading of knowledge, developmental assistance and insurance of loss.

You may also be interested in the following In-depth Report:

The Multifunctionality of Green Infrastructure (March 2012)Green Infrastructure (GI) stands to improve quality of life in many ways, through its environmental, social and economic credentials, based on the multifunctional use of natural capital. Potentially a very valuable policy tool, GI’s multifunctionality could contribute to the achievement of a number of policy aims and fulfil the needs of a variety of stakeholder groups.

To view any of these in full, please visit: http://ec.europa/science-environment-policy, and search according to publication date.

To receive articles like this in a free weekly News Alert, please e-mail your subscription request to sfep@uwe.ac.uk