How do bottom-up climate adaptive initiatives contribute to a healthy environment in the city? A research into the possibilities of using a bottom-up strategy to achieve a healthy city

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How do bottom-up climate adaptive

initiatives contribute to a healthy

environment in the city?

A research into the possibilities of using a bottom-up strategy to

achieve a healthy city

Wilco van Varik

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June 2018

Bachelor Geography, Spatial Planning and Environment

Author: Wilco van Varik (s4608720)

Radboud University

Word Count: 59536

Supervised by:

Professor Peter Ache

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Preface

Last 3 months I had the opportunity to specialize myself in a specific theme of interest through writing my thesis for my Bachelor Geography, Spatial Planning and Environment (Geografie, Planologie en Milieu). My main topic of interest is the connection between cities and nature. The earth is one big system where everything is connected to each other. Even in cities, where the connection is not directly visible, the physical environment is very important for the complete ecosystem. My personal dream is to create cities full of vegetation, where the link between man and nature is not broken but continued. Cities where residents live in a healthy physical environment and make healthy decisions, without any potential physical health risk such as a high concentration of fine dust in the air, or psychological risks such as social isolation. Cities with green gardens, parks, green roofs, green balconies, green walls and all the other innovative designs that will be presented in the future. Cities where you see birds flying around, and not only the dominant blackbird (merel), sparrow (mus) or pigeon (duif), but also owls (uilen), hawks (haviken) or kingfishers (ijsvogels). Cities where nature gets a chance of developing itself through different kind of vegetation. Not only planted flowers, but also wild flowers such as poppies (klaprozen), cornflowers (korenbloemen) or wild orchids (wilde orchideeën). A city full of different kind of insects such as butterflies (vlinders), dragonflies (libellen), ladybugs (lieveheersbeestjes) and grasshoppers (sprinkhanen). Cities where different kind of animals get a chance such as squirrels, weasels, hedgehogs and bats. Cities where there are small lakes to increase the evaporation and cooling in the city and to look after amphibians such as frogs, salamanders, turtles or even snakes.

To achieve the connection between nature and cities, is through thinking local. The environmental and sustainability movements already made a nice catchphrase for it: ‘Think global, act local’ (Schwarz, 2014). My main topic of interest to achieve ‘green cities’ are bottom-up climate adaptive initiatives, started by local citizens, companies or organisations. It requires knowledge of the local situation to see different opportunities, as well as different solutions for problems. All the bottom-up projects are different, which provides chances to integrate different aspects where it is needed and the most efficient. The bottom-up initiatives have the ability to integrate different aspects, exactly because all the bottom-up projects differ enormously (such as the geographical scale, resources available and actors involved). Exactly this difference, stimulates the creativity and flexibility necessary to integrate different aspects into the city. All projects have a different development and result, which brings in the power of diversity. There is no one correct solution such as only green roofs, neighbourhood gardens or vertical gardens, all projects have different strengths and need to be used in combination. Together the projects have the ability to create a ‘green city’. Whereas the power of setting up a

neighbourhood garden is strengthening the social cohesion and biodiversity of the neighbourhood, the social cohesion strengthened through building a green roof is limited. The power of the green roof in turn is to adapt the buildings to a changing climate on places where a neighbourhood garden is not possible. The projects need each other and build on each other. If we truly want to achieve green cities, multiple different solutions need to be found and integrated. Not only on a city level, such as the combination of different kind of bottom-up projects to integrate nature into the city (such as the neighbourhood garden and the green roof mentioned above), but also on an even smaller level: the integration of different green aspects into individual buildings.

An example of the integration of different aspects is the apartment complex below (figure 1). The apartment building has a green roof, trees on the ground (and on the second floor of the building!)

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5 and green façades.

The integrated character of the apartment building will make the building a perfect place for biodiversity to develop and flourish. Whereas only one green roof or one creeper might have a limited effect on improving biodiversity, all the different aspects integrated could make the apartment building a likely place to encounter different kind of insects and birds. A city full of buildings with vegetation integrated in combination with different kind of bottom-up projects such as parks, neighbourhood gardens, vertical walls, vegetated roofs or bins with vegetation, could create the green city I have in mind. If done on a large scale, the integrated character of all the different vegetated buildings and initiatives make the city a place where both humans and nature have a chance to develop.

Because of my interest in local bottom-up projects, I first started to focus on 2 bottom-up cases, which were carefully selected. When I had the interviews with the 2 cases I realised something: Not 1 or 2 bottom-up projects make the difference to the climate adaptability of the city, but all the projects together, the quantity of the projects. The projects differ enormously, which I recognized as the main strength of bottom-up planning initiatives. Whereas some projects focus primarily on biodiversity through creating areas with wild flowers, other people focus on improving a desolated piece of land to enjoy or to strengthen the social cohesion by working on it together. All projects focus on a different theme and together they have the ability to create a healthy physical environment, because they all focus on different aspects of a healthy physical environment. When the realization hit me, I decided to enlarge my thesis to other projects as well because of all the enthusiasm and inspiration I encountered in the projects. I quickly learned the value of having a network, because all the different initiators of the projects knew each other. The projects clearly had the ‘snowball-effect’, most of the time I immediately got new contact details for other projects as well. The projects inspired me on all the possible ways to integrate nature into the city with measures previously unknown for me, or at least the scale of some measures. Whereas I always thought that creepers (klimplanten) could provide a solution to greening the city, I underestimated the scale which creepers could take. An example of a

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6 source of inspiration is the Koningstraat in Arnhem, where no room is left for vegetation on the ground. Now the research is finished, I see more possibilities to green the city through integration of different aspects. In addition to the apartment building in figure 1, the creepers such as from the Koningstraat (figure 2) could also provide a valuable option to further integrate vegetation into the building.

In addition to bringing more vegetation into the city, the bottom-up initiatives also have other

beneficial effects. The projects are not only important for climate adaption, but also to strengthen the social cohesion in neighbourhoods: New friendships are forged through working together. Residents create something with the neighbours, which bundles all the energies of the people involved. The project binds people and creates a tighter street or neighbourhood. The vegetation also has a psychological effect, the city is experienced as a more pleasant place to live if more vegetation is added to the physical environment. The same happened to me, after the research I saw the city of Arnhem in a completely different light. Almost each street has its own traits and character, with different possibilities of integrating nature. The streets are already full of small projects, which were previous unnoticed for me. Now I know the story behind different projects, I will definitely pass by more often to see how the projects develop.

I also learned that a sole focus on the result, is not going to help you any further. Whereas some projects do not have the greatest results for making the city climate adaptive or green, the projects are important for other aspects. All solutions are different, but all projects bundle the energy of the people involved and contribute to the creation of a ‘green’ city in their own way. Because of the inspiration and enthusiasm I encountered in the different projects, the number of cases investigated multiplied by five. To clearly demarcate the cases, I only investigated cases which were directly connected to the platform ‘Arnhem Klimaatbestendig’ (Arnhem Climate Resilient’) which has the goal of linking the climate projects and educating about the effects of a changing climate on the city. I still have a lot more contact details for other projects as well, which unfortunately I couldn’t investigate because of the amount of time. Now, at the end of the thesis, I also strongly feel part of the network. The people behind the projects are not just the initiators of cases I investigated, but people I feel

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7 connected with and probably will see in the future more often. You could always contact me for questions or ideas, see the telephone number below.

I want to thank all the people involved in my thesis, who helped me with valuable information, contact details or even further invitations. In special, I want to thank my thesis mentor Peter Ache. Not only for his expertise, but also for his personal interest and belief in me and my thesis.

Wilco van Varik (+31624451052) Nijmegen, June 2018

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Summary

Cities are the future. Whereas only 39% of the people lived in cities, in 1980 (Da Silva, Kenaghan & Luque, 2012, p.125) the number rose to 52% in 2011 (Da Silva, Kenaghan & Luque, 2012, p.125) and is expected to rise to 70% in 2050 (Da Silva, Kenaghan & Luque, 2012, p.125). The increasing number of people in cities also require more energy. Already 60-80% of the energy in the world in consumed by cities (UNEP, 2015, p.2), which is expected to rise because developing countries are quickly catching up with developed countries (Hoornweg, 2010). Cities are valuable because of the economic wealth that is stocked here, as well as the influence of the city on influencing so many lives (Dulal, 2017). The city has a direct influence on the wellbeing of the residents (Dulal, 2017). The urban is already a complex system, because changes in one part could induce changes in other parts of the city as well (Da Silva, Kenaghan & Luque, 2012). At the same time, a changing climate is also posing new threats on cities (C40cities, 2012). With the even more important role of cities in the future, climate adaptive measures could provide a solution to reduce the negative effects of a changing climate on the city. Different models have been devised to address climate change, with the top-down approach quickly falling out of favour according to various actors (Diringer, 2011; Prins & Rayner, 2007; Tollefson, 2011; Victor, 2009). The imposed vulnerabilities of climate change differ strongly between different parts of the city, with a lot of insecurities

(Rovers, Bosch, Albers & Spit, 2014). Different parts of the city have different risks, which makes small and local measures the most efficient

(Rovers, Bosch, Albers & Spit, 2014). This is exactly what is promoted by the government of The Netherlands through introducing the new Environment and Planning Act. One of the biggest legislative operations in the history of The Netherlands. Several different planning methods have passed, with the current planning method trying to facilitate and empower local actors to start initiatives (mijnOmgevingsvisie, 2013). The new planning method is called ‘uitnodigingsplanologie’ and is strongly tied to the new Environment and Planning Act. The process of beginning a project for local actors is strongly facilitated (Rooy, 2011), the attitude is changing when local actors want to start an initiative from ‘no, unless…’ to ‘yes, but…’ (mijnOmgevingsvisie, 2013). Whereas the process of beginning a project or initiative could be very tardy and exhausting in the past with different contradicting rules and permits, local actors now only need to ask for one permit, digitally

(mijnOmgevingsvisie, 2013). Important in this regard is the local area. Every local context is different, with different desires and needs. A bottom-up provides exactly the flexibility to make little local differences for a climate resilient city. The research provides 10 different cases, roughly divided over 5 citizen projects and 5 professional projects in the city of Arnhem. The research shows that the projects differ enormously, which makes generalisations almost impossible. But instead of seeing the

difference of bottom-up projects as a weakness of the planning strategy, the differences are the strength of bottom-up. With more and more people living in cities, the life that citizens experience in the city is getting more and more important. The Rijksinstituut voor Volksgezondheid en Milieu (RIVM) made a list of 10 categories which are important to achieve a healthy physical environment for people to live in (2011). The research shows that all projects focus on different categories and all together create the real ‘healthy’ physical environment from the RIVM. All projects have specific strengths, such as the goal of a neighbourhood garden for people to meet each other, or the strength of a vertical garden to improve climate resiliency. But all projects also have small weaknesses. Whereas a green roof could be important in climate adaptation and mitigation, the stimulation for people to meet each other could be limited. If local actors would set up a neighbourhood garden, new

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9 connections between people could be made, which intercepts the weakness of the green roof as a low stimulator for forging new connections between people. Important is to specify what the area needs and to think local: If room is available and social cohesion is a problem in the neighbourhood, a neighbourhood garden could be a good solution. But if social cohesion is not problem in the

neighbourhood, but there is simply no space for any vegetation, perhaps bins with vegetation, green roofs or vertical walls could be a solution. The bottom-up projects empower each other through focussing on different categories and intercepting the small weaknesses of other projects. Thus, the difference of the bottom-up projects is not a weakness of the bottom-up approach, but a strength. Important is to increase the number of bottom-up projects and to create as much different projects as possible to create the healthy physical environment from the RIVM through fulfilling all the different categories. Focus on the local desires and needs of the area and on local actors such as residents, organisations or companies because these actors know the qualities of the area the best. An important aspect of the research was climate adaptation and mitigation measures, and specifically what could be done to increase the number of projects to create cities full of vegetation and a healthy climate for people to live in. Important is to see the projects not individual, but together. Perhaps one green roof is not going to stop the Urban Heat Island (UHI) effect, but what about 100 green roofs? Together the roofs could be a valuable measure to achieve a climate resilient city. Important is to increase the number of bottom-up initiatives to create the biggest effect. As mentioned before, not only the amount of project is important, but also the difference of the projects. To create a natural ecosystem with a healthy environment for people to live in, does not require only green roofs, but also neighbourhood gardens, vertical roofs, vegetation on balconies, vegetation in mobile bins, creepers along the walls or though creating a small park. Projects don’t have to be big, small adjustments such as removing the tiles out of the garden could already make a real difference if it done on a large scale. A city full of vegetation could be created, but only together.

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Reading guide

The thesis is divided into 9 chapters. Below is an outline of all the chapters with the most important content.

Chapter 1 is the introduction which sketches the project framework, the background through which the research is conducted. The first chapter is divided into 7 parts, the first 3 parts are an introduction into the thesis. The first chapter is about climate change, especially the consequences of a changing climate for cities. The next chapter is about the role of vegetation in mitigating the effects of a changing climate on cities. The third part is about the measures taken in the city of Arnhem: A bottom-up approach. The platform ‘Arnhem Klimaatbestendig is stimulating and empowering local actors to take action so together a climate adaptive and green city could be created. The remaining chapters are subsequently the research objective, research questions, research relevancy and the research design.

Chapter 2 is the context of the research, which could better be understood as the motive of the research. The Dutch planning culture is changing from a top-down approach to a bottom-up approach. The introduction of the Environment and Planning Act in 2021 further promotes a bottom-up

approach through inviting and local actors to start initiatives through facilitating the process. Therefore, a bottom-up strategy (just as investigated for Arnhem) could become even more important.

Chapter 3 is the theoretical framework which leads to important concepts, such as climate change governance, civic environmentalism, localism, vital coalitions and a healthy environment. Throughout the chapter, different parts of the eventual conceptual model are introduced to keep the information clear. The chapter is ended with the complete conceptual model, where all the different parts of the conceptual model come together.

Chapter 4 is about the methods used. The research has chosen to do 10 case studies. The information is gathered through analysing documents, qualitative interviews and a questionnaire.

Chapter 5 describes the 10 case studies chosen. The cases are numbered from 1 till 10 and have the same layout. Each case is introduced through visualizing the results in pictures, followed by a short introduction of the executed project (1) and the actor network (2). Subsequently, the development of the project from idea to executed project is researched (3.1), the motives behind the project (3.2), the relevant themes (3.3), the role of entrepreneurs (3.4), the role of leadership (3.5) and the role of the government (3.6). Each case is ended with a research into the results of the project on a healthy physical environment.

Chapter 6 lists the results of the research. The research takes all the results of the cases from chapter 5 and analyses the differences and similarities.

Chapter 7: Lists the most important conclusions of the research, which could be best described as the use of bottom-up projects and the very essence of a bottom-up approach.

Chapter 8 is the last chapter, which covers the reflection, which provides pitfalls of the research, as well as confronted problems

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1. Research framework

What is the content of this chapter?

The chapter introduces the reader to the topic of climate change through a combination of literature study and physical geography. The chapter discusses why cities are especially important to focus on and discusses the specific threats specifically for cities imposed by climate change. A special section is

added for the role of vegetation in adapting the city to reduce the threats. The research then narrows down to the city of Arnhem, where the specific threats imposed by climate change are visualized. The city of Arnhem is already making an effort to adapt the city to a changing climate through increasing the amount of vegetation. The individual (bottom-up) projects are united in the platform ‘Arnhem Klimaatbestendig’. In the last sections of this chapter, the research objective, the research questions, the relevance of the research and the research model will be discussed. The goals of the chapter are to introduce the topic of climate change and the negative effects on cities,

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1.1 Climate change

1.1.1 The history of climate change

28 of March 2018, Trujillo (Peru) - Archaeologist have found the immemorial skeletons of 140 children aged between 5 and 14 years old with the diaphragm cut open and the hearts taken out (National Geographic, 2018). The children are probably offered by the Chimú, the precursors of the Inca’s, together with 200 lamas. People only offer the most valuable things they have, which only could imply a big crisis in the Chimú society (National Geographic, 2018). Excavations in the soil found different layers of soil with heavy rain and inundations. What the Chimú experience, was a changing climate: Instead of a dry area, the Chimú experienced heavy rain and inundations (National Geographic, 2018). Unable to cope with the insecurities, the only way out seemed to please the Gods, through the offering of the most valuable they had: The children (Verano, 2018).

The short introductory story shows that climate change is not a new problem. The climate has changed many times in the past, differing greatly in magnitude (Marsh & Kaufman, 2013). One thing is for sure: Climate change is not the exception, but the norm for life on earth (Marsh & Kaufman, 2013, p. 172). Some changes of the climate have been massive in the past, changing the entire

biogeographical character on the entire earth, whereas other changes of the climate had only limited effects on the biogeographical character. In the past, the temperature on earth have risen multiple times, because of the difference between glacials and interglacials. The interglacials were the warm intervals between the cold glacials. Figure 3 and 4 show the variation in temperature, starting 24.000 years ago. The peak of the last glacial ended 18.000 years ago, where 12.000-14.000 years ago global temperatures suddenly started to rise again, cooled, and rose again 10.000 years ago (Marsh & Kaufman, 2013, p. 177). Temperatures have been rising ever since, with oscillations of 2 °C degrees every 2000 years or so. Earth is still in an ice age but is now in an interglacial interval interrupted by short cold spells (Marsh & Kaufman, 2013, p. 177). Around 2000 years ago (AD 500), temperatures started to rise further again, which made agriculture possible in Europe. The period from 1400 till 1850 is known as the ‘little ice age’ with temperatures falling again. Forests were quickly cut for fuel and building material. Take for example Great Britain who already had no forest left by 1700 (Marsh & Kaufman, 2013, p. 177). From 1850 temperature started to rise again steadily through ups and downs, together with the amount of population and land use. The Industrial Revolution caused the population to grow sevenfold from 1 billion to 7 billion, spread over the entire world (Marsh & Kaufman, 2013, p. 179). Around 12% of the forest and grassland is converted to cropland for food production, combined with massive city centres, industry and 800 million automobiles (Marsh & Kaufman, 2013, p. 179). All contribute to the contamination of the atmosphere through emitting carbon dioxide and aerosols from the urban centres, cars and industry.

Figure 4: Climate change in the past (24000 years in the past). Source: Marsh & Kaufman, 2013

Figure 3: Climate change zoomed in from 500 AD to the year 1900. Source: Marsh & Kaufman, 2013

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15 It is important to understand that these data are not a wide estimation. Climate change has happened (and is happening!), which is clearly measurable. There are clear environmental and historical

indicators of climate change, called proxies. Different proxies for measuring past climates are used, which help to determine climate change in the past. Proxies for temperature are for example shells of ocean organisms found in ice sheets to measure the amount of the two isotypes oxygen-16 (16_{O) and}

oxygen-18 (18_{O) (Marsh & Kaufman, 2013). Antarctica and Greenland form a perfect place to drill for}

old ice sheets and compare the amount of 16_{O and}18_{O. The deeper the ice, the older the ice is. Also,}

the fossil remains of certain organisms, for example reptiles or flowering plants, could help to determine the temperature in the past to relate them to a particular temperature level. Bones of reptiles could be compared with living conditions in areas, for example bones found in particular places indicate a certain temperature because the reptile could live here. Plants are also important indicators, because the leaves indicate the air temperature (Marsh & Kaufman, 2013, p.173). Whereas smooth margins of leaves are related to tropical conditions, the small jagged margins are related to colder climates (Marsh & Kaufman, 2013, p.173). The fossils of the leaves could be used to measure dates up to 100.000 years ago or more (Marsh & Kaufman, 2013, p.173). The pollen of the plant is also important, because pollen found on a distant place far from the normal area could indicate a changing climate as well. Also, when organisms suddenly disappear, there is a strong indication of a change in the thermal climate (Marsh & Kaufman, 2013, p.173). In addition, another good measure is tree rings. Large rings indicate a good year with favourable climatic conditions so the tree could grow rapidly, the small rings indicate unfavourable climatic conditions with less growth. Tree rings are helpful in indicating heat and moisture changes in the climate, the periods dated could go back as far as 10.000 years ago (Marsh & Kaufman, 2013, p. 174). Finally, historical records and archaeological remains are valuable to estimate climates in the past, because the records could date back to 6000-7000 years (Marsh & Kaufman, 2013, p.174).

1.1.2 Climate change today

Humanity is facing one of the biggest environmental challenges now: The climate is changing, which in turn will affect everything on earth. Because of huge amounts of fossil fuels, livestock and the cutting down of forests, the earth is crying out for help because of the increasing level of carbon dioxide (Simon-Lewis, 2018). The climate is changing because of increasing amounts of greenhouse gases in the atmosphere, the most important greenhouse gases are carbon dioxide (CO2) and methane (CH4)

(Holden, 2008). These gases form a blanket around the earth through which heat is easily admitted but more difficult reflected back into space so partly stays into the atmosphere on earth (UNFCCC, 2007). Because of this greenhouse effect, the temperature is rising, with global warming as a result (see figure 5). In the past, climate change was very uncertain, but now it is unequivocal. The carbon dioxide levels are higher than the past 800.000 years (Lindsey, 2017). The highest parts per million of atmospheric carbon dioxide ever reached in this period was 300 ppm 300.000 years ago, with currently 402,9 parts per million. (Lindsey, 2017). The global growth rate of carbon dioxide has risen from 0,6 ppm in the 1960’s to 3,5 ppm today. This is

almost a rise of 483%! (Lindsey, 2017).

Figure 5: The rise of carbon dioxide into the atmosphere. The graphic is based on the data from NASA. The number 0 is the level of carbon dioxide for the period 1961-1990. Source: Marsh & Kaufman, 2013)

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16 The results of climate change are disastrous. To begin with, higher temperatures are causing many types of disasters including storms, floods, droughts and heatwaves. The weather pattern is changing with wet areas becoming wetter, and dry areas becoming drier (Dijksma, 2016). These extreme conditions are a direct risk to public health and safety, with more out-of-control forest fires, lack of drinking water, endangered food security and agriculture, extreme heat events, dust storms and massive floods (UNFCCC, 2007). Also, indirect effects contribute to this health effect. Take for example the fact that increased air pollution leads to more asthmatic and cardio-vascular diseases, increased allergies or heat strokes (UNFCCC, 2007). Not only does climate change cost lives, also the damage to property is severe. The National Oceanic and Atmospheric Administration states for example that weather and climate disasters in the US caused 1 billion dollars of damage in the year 2015 only (NRDC, 2016). In addition, higher wild life and plant extinction rates will occur because animals and plants can’t adapt to the new weather patterns and conditions. Bellard, Bertelsmeier, Leadley, Thuiller & Courchamp (2014) estimate that more than 16% of the European landmass will have extinction rates exceeding 50% by 2050. In addition, the oceans are warming up, with acidification as a result. The consequences are severe, not only ecological but also economical because humans depend on fishery for their existence (UNFCCC, 2007). The species most affected are creatures with calcium carbonate shells, because shells are dissolving in more acidic water, which is disrupting the food chain and is causing losses everywhere in the ecosystem which depends on these shellfishes (Brander, 2007). This has important consequences on the economic viability of fisheries in the world, the University of British Colombia states that future fisheries can expect a loss of 10 billion dollars for fisheries around the world (2016). Thereby, the oceans are also rising, threatening all coastal regions in the world. The consequences are undeniable for cities as Rio de Janeiro, Mumbai, Sydney or Miami. Over 90% of all the urban areas in the world are coastal, which makes them vulnerable for a rising sea level or severe storms (c40Cities, 2012). To effectively fight all of these negative consequences, climate adaptation measures are required. The chapter continues with a specification on cities. Why is it relevant to focus on cities?

1.1.3 The prominent role of cities in fighting climate change.

Cities are considered as complex ‘living’ systems because of the ongoing changes at any time, constantly evolving and responding to internal and external pressures (e.g. climate change) (Da Silva, Kenaghan & Luque, 2012). The city is a system, therefore changes in one element of system could induce changes in other parts of the system as well (Da Silva, Kenaghan & Luque, 2012). Cities are also an important factor in climate change: All cities in The Netherlands are vulnerable for a changing climate, whether the city is small or big (Rovers, Bosch, Albers & Spit, 2014). Around 70% of the cities already feels the consequences of a changing climate (C40cities, 2012). A new era has come, with most of humanity living in urban towns and cities (United Nations Human Settlements Programme, 2011). Already 40% of the population of The Netherlands lives currently in the 36 biggest cities (Rovers, Bosch, Albers & Spit, 2014). This number is quite low compared with other countries in the world, the percentage of people living in cities around the world is 54% (UN, 2014). The year 2008 was the official turning point in history, for the first time more than half of the global population lived in cities (United Nations Human Settlements Programme, 2011). The number of people living in cities is expected to grow, worldwide the number of people living in cities is expected to grow to 66% in 2050 (UN, 2014). Different researches give a slightly different number, such as 70% from Da Silva,

Kernaghan and Luque (2012). Important to note is that the urbanisation rate is the highest in Africa and Asia, where the population is expected to double between 2000 and 2030 in cities (United Nations Human Settlements Programme, 2011). The developing world is especially important, since the towns and cities of the developing world will amount 81% of the total urban population living in cities (United Nations Human Settlements Programme, 2011). Shariat (2014) mentions that more than 60% of the cities that will exist in 2050 are not even built yet. The urbanization is often linked with economic growth in most of the countries, the cities drive economic development (United Nations

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17 Human Settlements Programme, 2011). Economic development in turn, stimulates the urbanization even more. Important to note is that this is not always the case, countries in sub-Sahara have seen a high urbanisation rate, but low economic development (United Nations Human Settlements

Programme, 2011).

The rapid urbanisation has also important consequences for the demand for energy and transport. According to the United Nations Environment Programme (2015, p.2), already 60-80% of the energy in the world is consumed by cities. Other authors have slightly different numbers, such as 66% from c40Cities (2012). The amount of greenhouse gases emitted by cities on a global scale is 67%

(International Energy Agency, 2008, p.183). Other actors show similar percentages, such as C40Cities (2012) that large cities already emit 70% of the global carbon dioxide emissions through consuming 2/3 of the worlds energy (c40Cities, 2012). This number is expected to rise to 74% by 2030

(International Energy Agency, 2008, p.390). Developed countries are consuming the most, but the increase in consumption by developing countries is rising quickly. The GHG emissions of developing country range between 26% and 33% of the total emissions and are rising quickly. It is estimated that 89% of the total increase in CO2 from energy will be done by developing countries (International Energy Agency, 2008, p.390). Rising urban incomes, increasing affordability of private cars and the unreliable public transport system (because of overcrowding) will increase the numbers of cars in cities in developing countries. An example is China, where the energy demand and GHG emissions from road transportation alone will be expected to reach 734 million tons of oil and 2.38 tons of carbon dioxide in 2050, which will be 5,6 times greater than at 2007 level (Dulal, 2017, p.106). Another example is India, where the gasoline and Diesel consumption has quadrupled between 1980 and 2000 (Dulal, 2017, p.106-107). As a consequence, urban emissions such as greenhouse gases (GHGs: CO2, N2O, CH4 and SF6) increase (Dulal, 2017). Cities in developed countries are better

positioned against the negative impacts of climate change because of the overall size of the economy and the municipal tax base (Dulal, 2017, p.106). Developing countries are worse positioned against the negative impacts because of the state of the economy and subsequently the lower tax base (Dulal, 2017, p.108).

The urbanization rate has consequences for the residents of the city. Cities are important because of their role to take care of the well-being of the population (Da Silva, Kernaghan & Luque, 2012). At this moment, one in three urban dwellers already lives in a slum with overcrowded conditions inadequate access to water, sanitation, poor quality shelter or lack of tenure (Da Silva, Kernaghan & Luque, 2012, p. 125). These vulnerabilities will be worsened because of the adverse of climate change, which is likely going to increase the number of city dwellers in bad conditions (Da Silva, Kenaghan & Luque, 2012). The impact of climate change on the urban system is substantial because of its impact on a very large number of people. In addition, especially in low-and middle-income countries, there is a direct link between urban poverty, vulnerability and climate change, which means that the people who are least able to cope, are likely to be hit the hardest (Da Silva, Kenaghan & Luque, 2012). Different sources note the importance to create a healthy environment in the city. c40Cities (2012) for example notes the possibility of a better quality of life and a lower carbon footprint if more efficient

infrastructure and planning would be used. Cities have also become the focus point of possible to fight climate change, recognized in intergovernmental agreements (e.g. The United Nations Sustainability Development Goals and the Paris Agreement) and institutionalized in international networks (e.g. C40 Cities and Local Governments for sustainability) (Bulkeley, Broto, Hodson & Marvin, 2011).

A high concentration of people in the city has important consequences. The more people in the city, the more opportunities for interaction and communication which could stimulate creative thinking,

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18 knowledge spill overs and new ideas and technologies (United Nations Human Settlements

Programme, 2011). Cities are the centres of artistic, scientific and technological innovations, culture and education (United Nations Human Settlements Programme, 2011). The diversity and density of cities makes people more productive and innovative (URBACT II, 2015). Rovers et al. (2014) also note that cities are important because they are the centre of civilization, life and knowledge. More specifically, as history has proven, cities are the birth of civilization (United Nations Human Settlements Programme, 2011). The concentration of people and economic capital makes the city important for the well-functioning economy and society. The OECD (2014) convincingly argues for an increased focus on cities because cities can be the drivers of national growth and recovery. Cities are of major importance for economic wealth (Da Silva, Kernaghan & Luque, 2012). Cities are important for economic development because cities provide economies of scale, agglomeration, and localisation (United Nations Human Settlements Programme, 2011, p.1). The city provides efficient infrastructure, and services as well through the density and concentration in transportation, communications, power, human interactions, water and sanitation services (United Nations Human Settlements Programme, 2011, p.1). In addition, the city attracts talents and skilled labour which provides further possibilities for specializing in knowledge, skills or management capabilities cities (United Nations Human Settlements Programme, 2011, p.1). This is also stressed by Shariat (2014), who shows that most of the innovations occur in the cities through knowledge-sharing and creativity. This is not only a tale to glorifies cities, but it is also proven. Take for example the research from Dijkstra (2013) who proved that smaller and medium sized cities in Europe were important economic engines.

Climate change jeopardizes the financial health of cities through unexpected expenditures such as after storms, flooding, snow removal and droughts which require major expenditures from the city budget or disruptions in the operation of businesses (C40cities, 2012). Cities could reduce these negative impacts. Cities determine and influence the urban environment in the city, such as the built environment, public transport systems, infrastructure development and management, water and waste management, disaster risks management and public service delivery (Dulal, 2017). Urban interventions could address problems in these areas, while also integrate climate change mitigation and adaptation (Dulal 2017). Such situations could lead to win-win situations (Dulal 2017), for example through integrating green materials (e.g. green roofs) standardly in the built environment or new infrastructure. Especially important is urban planning, different actors show that urban planning acts as a key policy lever to reduce urban emissions and enhance climate mitigation and adaptation benefits (Davoudi et al. 2010, Wilson and Piper 2010, Dulal and Akbar 2013). An example of the results of a different form of urban planning is in Curitiba, Brazil, where the population is rising quickly which led to congestion, pollution and reduction of public space (Davoudi et al. 2010, Wilson and Piper 2010, Dulal and Akbar 2013). Through a different form of planning, there is now a new situation in the city without congestion or pollution, with the average green area available for each person 50 km2 _(Instead

of 1 km2_{(Dulal, 2017, p.109). So, what is the difference between climate mitigation, adaption and}

resiliency?

1.1.3 Climate mitigation, climate adaptation and climate resiliency

The responses to climate change in the city are difficult because of the inherent uncertainties in climate projections, the lack of evidence on how to achieve climate resiliency and the complex interactions that are active in the city (Da Silva, Kernaghan & Luque, 2012). What is known is that climate change is imposing substantial risks to cities, but the specific risks and the effectiveness of possible solutions is still mostly unknown (Da Silva, Kernaghan & Luque, 2012). The two most important responses to reduce these risks are: Climate mitigation and climate adaption. Important is to make a distinction first between climate mitigation and climate adaptation, because both have

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19 different goals and measures to be taken. To begin with, climate mitigation is about “limiting global climate change by reducing the emissions of greenhouse gases or enhancing their sinks” (Füssel, 2017, p.265). Climate adaption means “Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities” (McCarthy et al. 2010, p.982). But also other definitions are used, such as the definition of the Intergovernmental Panel on Climate Change (2007): “climate change adaptation refers to initiatives and measures to reduce the vulnerability of natural and human systems against actual or expected climate change effects”. Whereas mitigation is dealing with causes of climate change and works to reduce man-made effects on the global climate, adaption is preparing possible measures to prepare for and negate the effects of climate change. This is closely linked to another term: Climate resiliency. The United Nations Office for Disaster Risk Reduction (UNISDR, 2012, p.92) defines resiliency as: “Resilience means the ability of a system, community or society exposed to hazards to resist, absorb, accommodate to and recover from the effects of the hazard in a timely and efﬁcient manner, including through the preservation and restoration of its essential basic structures and functions”. Climate resiliency is about the management of a climate-imposed risk. Climate adaptability measures are part of the broad ‘resiliency’ framework to manage risks by different projects and initiatives. Until recently, the discourse amongst planners has mainly focussed on climate mitigation (reducing carbon dioxide), but now there is a growing attention in the fields of policy, research and practice for climate adaption (Garter et all, 2015).

1.1.4 From top-down to bottom-up

The renewed focus on cities could also be explained by a shift from top-down to bottom-up. Global climate change agreements started with The United Nations Framework Convention for Climate Change (UNFCCC) in 1992. The UNFCCC has received remarkable support from within the

international community, “it has near universal membership” with 197 countries (UNFCCC, 2007). The convention came into force in 1994 and in 1997 the Kyoto-protocol was signed, which added

innovative and flexible mechanisms to achieve reductions in GHG-emissions (Andresen, 2015). The Kyoto protocol failed to induce significant reductions on a global scale because some of the world’s largest greenhouse emitters (e.g. the US, China, Brazil, India & South Africa) did not ratify the protocol (Grunbaum, 2015). Ever since the Kyoto protocol, the process of deliberation is slow: 4 years were needed to understand the precise meaning of the protocol and another 4 years passed before the protocol entered into force (Andresen, 2015). The Kyoto protocol is a top-down approach, which might not be suitable to address climate change (Dirix et al., 2013). According to Dirix et al. (2013) national leaders have ignored the fact that climate change is a multilevel problem, which makes every vertical level vulnerable through a mix of affected groups and a growing number of cross-border interest and coalitions (Dirix et al., 2013, p. 366). A key term to fight climate change is governance. Governance arrangements are important in cities to offset climate damage and enhance opportunities linked to climate chance hazards through proactive, responsive strategies and creating networks of stakeholder groups. At the 15th_{meeting from the Conference of Parties of the United Nations}

Framework Convention on Climate Change (UNFCCC) in 2009, The Copenhagen accord was signed (Dirix et al., 2013). Voluntary commitments were made in Copenhagen, but the conference did not lead to any binding results to reduce GHG-emissions. Countries all pledged to reduce the GHG emissions so the increase in temperature would not be more than 2°C above pre-industrial levels and ‘dangerous anthropogenic interference with the climate system’ would be avoided (UNFCCC, 2009, p.5). While the policies are formulated on the threat that the temperature rise will only amount 2°C, sources indicate that that the rise in temperature will be at least 4°C (Betts et al. 2011). It is clear that action is required to avoid the rise of 4 °C in temperature, many people considered the Copenhagen Accord as failed because no binding results were created (‘The Copenhagen failure’) (Bäckstrand &

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20 Lövbrand, 2016). Even though the Copenhagen accord was a disappointment for stronger action, the accord contributed to a new approach to address climate change (Andresen, 2015). Since the Copenhagen accord, a more bottom-up approach is chosen to address climate change through voluntary commitments (Dirix et al., 2013), for example through projects in cities. The bottom-up projects promote learning-by-doing, build ‘coalitions of the willing’, break up projects into more manageable elements, disseminate knowledge, show best practices and contribute to policy learning. (Bulkeley & Newell, 2010). The basic proposition of a bottom-up approach is that initiatives should be done at the lowest level as possible (Roos, 2010). Since the turn of the century, local and regional authorities in Europe are starting to make cities climate resilient or ‘climate proof’ (Swart, Sedee, De Pater, Goosen, Pijnappels & Vellinga, 2014). Whereas a top-down approach is generally driven by science, a bottom-up approach is driven by the what is politically and economically feasible in a country (Andresen, 2015). Thereby, the approach is more flexible because the approach could fit with the local contexts of different cities, neighbourhoods or streets. The flexibility is not always

experienced as positive, for example Andresen (2015, p.18) describes bottom-approaches as “clumsy”. Important to note is the difference in vulnerability to climate change. The vulnerability differs strongly between cities and strongly within cities themselves (see 1.3 for the case of Arnhem) depending on the properties of the district, building style and the distribution of sensitive persons and objects

(Rovers, Bosch, Albers & Spit, 2014). Take for example exposure to heat and flooding, which is mainly determined by the amount of paved area and the density of the buildings in the district

(Rovers, Bosch, Albers & Spit, 2014). Considering the strong differences between different parts of the city, small and local measures are the most efficient. The vulnerability to the effects of a changing climate are determined locally, so the responds should also be determined locally, dependent on the local context (Rovers, Bosch, Albers & Spit, 2014). Measures taken on higher levels such as the city, regional or national could be a mismatch with the local context. A bottom-up approach to climate change could help to fit measures with the local context.

1.1.5 Climate adaption in The Netherlands

Dutch cities are preparing for these effects of climate change. The most important consequences of a changing climate in The Netherlands are heavy rain, periods of droughts, heat and the consequences of intense flooding (see figure 6) which result in damage, nuisance, sickness, premature death and negative changes in the quality of the environment and the ecosystem (Dijksma, 2016).

Dry periods Warm periods More wet periods A Rising sea level

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21 The main effects and their consequences

are visible in figure 7 below. The national strategy to overcome the negative consequences of climate change is the National Climate Adaption Strategy 2016 (Nationale klimaatadaptatie strategie, 2016) together with the Deltaprogram (De Deltaprogramma’s, 2015). These together constitute the climate adaptability measures for The Netherlands. Important components are connecting parties and the promotion of coordinated approach. Figure 7 explains the effects of a changing climate on the 9 sectors in the Netherlands. There are consequences for 9 sectors: Safety (veiligheid), IT/telecom

(IT/telecommunicatie), energy (energie), infrastructure (infrastructuur), recreation and tourism (recreatie en tourisme), health (gezondheid), nature (natuur), agriculture (landbouw) and water/space (water en ruimte). For the specific effects, please look at Appendix 1. The two most important threats for cities are the Urban Heat Island effect and increased chance of flooding. The next 2 sections will explain both threats. 1.1.6 The Urban Heat Island effect

The Urban Heat Island (UHI) effect has already been discussed in the literature for almost a century (Rovers, Bosch, Albers & Spit, 2014). The city is almost always warmer than the surrounding areas, which is called the Urban Heat Island effect (Rovers, Bosch, Albers & Spit, 2014). Global warming does not only increase the daytime temperatures of cities, it also increases the temperature at night. The temperature difference between cities and the surrounding area could be as much as 12 °C, with the biggest differences occurring mostly at night time (Rovers, Bosch, Albers & Spit, 2014, p.12). The difference between Dutch cities lays between 3 and 7 °C (Steeneveld et al., 2011). Figure 9 shows the temperature difference because of the heat island effect, with the left image visualizing the daytime difference in temperature, and the right image the difference in temperature in the night. During the day, a surface is heated with ‘short radiation’ directly from the sun, which is transported back into space as ‘long radiation’ (Holden, 2008). The city cools more slowly than the surrounding areas, because of the amount of paved and built surfaces is higher in relation with the vegetated areas (Rovers, Bosch, Albers & Spit, 2014, p.11). Where the transport of ‘long radiation’ is very fast in the surrounding areas of the city, the city releases the heat very slowly (Holden, 2008). The most

influential factors in determining the Urban Heat Island effect are the proportion of built surfaces, the height of built surfaces, the number of paved areas and the proportion of vegetated surfaces (Rovers, Bosch, Albers & Spit, 2014, p.11). A visualization of the Urban Heat Island effect could below (figure 8). The picture is taken with a heat sensitive camera, which allows to see the difference in temperatures in specific areas. Important to see in the picture are the blue areas (which represents a low

temperature) in relation to the orange and red areas (which represents a higher temperature). The areas around the trees are all cooler because of the shades of the tree and the cooling effect, in relation to the orange/red paved areas and roofs. Figure 9 shows the Urban Heat island in the Netherlands, with the left image the day time temperature difference, and the right picture the night time differences.

Figure 7: The 4 climate trends and their main effects on 9 sectors: Safety, IT, energy, infrastructure, recreation and tourism, health, nature, agriculture and water/space. Source: Dijksma, 2016.

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22

Figuur 8: The Urban Heat Island Effect visualized in the city. Source: City of Melbourne, 2017

1.1.7 Floods in the city

A changing climate also causes more days with extreme rainfall (Rovers et al., 2014, p.8). Cities are very vulnerable for extreme effects. Where the effects of more days with extreme heat has mostly

Figure 99: Daytime and night time differences in temperature. Whereas the red colour indicates a large difference, the blue colour indicates (almost) no difference. Source: Rovers et al. (2014)

Figure 8: The Urban Heat Island Effect visualized in the city. Source: City of Melbourne, 2017

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23 effects for the health of people, the effects of more extreme rainfall have mostly effects on the capital goods through the increasing risk of floods (Rovers et al., 2014, p.34). Buildings, especially the interior of buildings, are very vulnerable for increased flooding. In particular electric devices such as switch boxes (Rovers et al., 2014, p.34). Damage could also occur through the interruption of activities, traffic disturbances and power cuts through damage (Dijksma, 2016). In turn, extreme weather conditions could also cause an increased pressure on emergency services and an increased chance of

dysfunctional hospitals or roads to access the hospitals (Dijksma, 2016). Cities are getting more vulnerable than decades ago because of the more expensive and intensive design

(Rovers et al., 2014, p. 44). Extreme rainfall and floods could cause more damage these days because of the increased economic importance of the city, which makes them extra vulnerable (Rovers et al., 2014, p. 44). The city is vulnerable through the large amount of paved area and buildings. Rain can’t soak directly into the soil and stays on the paved areas and buildings, with the only way out the sewer system. The increasing amount of extreme rainfall cause urban drainage systems to fail more

frequently, which could result in floods. According to Luijtelaar (2008), flooding already occurs in 90% of the municipalities in The Netherlands. Again, the amount of vegetation in the city could help to decrease the amount of extreme rainfall and floods through the ability of plants and trees to retain water and allow the rain to infiltrate into the soil, thereby reducing the chance of floods

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24

1.2 The importance of vegetation

A possible measure to reduce the negative effects of a changing climate on the city, could be to add vegetation. First, some physical geography. It is important to understand the specific qualities and effects of vegetation to understand the role vegetation could play in creating a climate adaptive city. 1.2.1 The functioning of a plant

Vegetation performs photosynthesis to grow. The process of photosynthesis is a difficult process, which is performed by plants to generate the food and energy needed for growth and cellular respiration (Holden, 2008). To perform photosynthesis, plants need sunlight (energy from the sun), water and carbon dioxide. The leaves of the plant are very important, because the leaves contain stomata’s and chlorophyll (Holden, 2008). Stomata’s are little pores in the leaves of a plant which take up the carbon dioxide out of the atmosphere (Marsh & Kaufman, 2013). The chloroplasts contain the chlorophylls, which take up the sunlight (Holden, 2008). Water is captured by the roots of the plants, and subsequently transported through the stem to the leaves of the plant (Holden, 2008). The plant creates oxygen as a by-product of the photosynthesis and glucose (sugar). The sugar is very important, because the sugar is the food from which the plant grows. Figure 10 visualizes the process of

photosynthesis. Plants are important because of the storage of carbon dioxide, one of the main greenhouse gases which drives climate change. Planting vegetation does not only help to adapt to a changing climate, vegetation could also help to mitigate climate change through reducing the amount of carbon dioxide in the air. Dulal (2017) for example notes the importance of urban forestry projects and community gardens because the vegetation increases the amount of carbon retained and stocked and helps to adapt the city to extreme events, such as periods of extreme heat or precipitation.

Figure 1010: photosynthesis explained. Source: Science and Technology Concepts Middle School.

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25 1.2.2. How does vegetation reduce the heat island effect?

Different authors have already shown the link between the amount of canopy cover (especially trees) and temperature. Vegetation is an influential factor in controlling temperature (Weng et al., 2004). Yan et al. (2014) demonstrated the significance between vegetation cover in urban park. The research shows that a 50% increase of vegetation, resulted in 0,6 °C decrease in temperature. Important is to explain the albedo first, which is the amount of incoming solar radiation reflected (Marsh & Kaufman, 2013). The higher the percentage of the albedo, the more heat will be reflected, and less heat will be available to heat the surface (Marsh & Kaufman, 2013). An important factor in the percentage of the albedo is the colour: Dark components reflect a low amount of radiation. For example, snow has an albedo of 80-95%, which reflects almost all the incoming solar radiation (Holden, 2008). To compare, asphalt has an albedo of 4-5% (Ramírez & Muñoz, 2012). Because the dark surface, albedo is taking up all the heat instead of reflecting it back into space. Thereby increasing the Urban Heat Island effect. To increase the albedo, vegetation could provide a solution. According to Lin et al (2011), vegetation creates an albedo 15% higher than the surrounding urban areas because the vegetation absorbs less heat and reflects more heat. Holden (2008) confirms this, even though Holden is not talking about a park, but about a small forest or meadow. Small deciduous forests have an albedo of 15-20% and meadows have an albedo of 15-25%, which is around 10-20% higher than the albedo of asphalt (4-5%).

Key to decrease The Urban Heat Island (UHI) is increasing the amount of evapotranspiration (figure 11), which is a contracture of evaporation and transpiration (Holden, 2008). Both are mechanisms to transport the water from the Earth surfaces back to the atmosphere. Evaporation is the process whereby the state of water is transformed from a liquid to a gaseous state. Evaporation requires a lot of energy, because a lot of energy is required to change the state from liquid to gas (Holden, 2008). Evaporation is important, because the energy is not used to gain temperature (sensible heat), but to change from state (latent heat), vegetated areas thereby release much of the energy as latent heat through vaporization and not as sensible heat. Transpiration is the process whereby a plant is

releasing water vapor through the small pores on the underside (the stomata’s) of the leaves (Holden, 2008). Both transpiration and evaporation work with the same mechanism: The plants or water bodies are both releasing water vapor into the air, thereby cooling the local atmosphere (if water is available). In addition, vegetation such as large trees could also provide more shadow in the city, which is also essential for cooling of the local atmosphere, as well as for the climate inside buildings (Emmanuel, 2005)

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26 1.2.3. How does vegetation prevent floods?

Vegetation is also important in handling the excessive precipitation in the city. Because of the large amount of paved areas in the city, the water run-off is high, with a low amount of water able to infiltrate into the soil. The removal of paved areas such as bricks or asphalt by vegetation increases the amount of water which is able to infiltrate into the soil, which is very important. More vegetation helps to take up the excessive water. Vegetation has 3 different ways of retaining water. First of all, water could directly infiltrate into the soil after a rain event, so the water run-off and pressure on the sewer lines and possible floods is decreased. The Science for Environmental Policy from The European Commission (2013) did a research about the water run-off difference between a 3x3 plot with asphalt, a plot with a maple tree and a plot with grass. Whereas the run-off from asphalt was 62% in winter and 53% of the total rainfall in summer, the run-off from the plot with the tree was respectively 26% in winter and 20% in summer. The plot with grass had the best results: The run-off was less than 1%. Important to note is the fact that not all bodies with grass have the same effect, only if the soil is not heavily compacted (European Commission, 2013). The city is heavily built, which brings in the

discussion to what degree the soil is compacted in the city and subsequently the effectiveness of grass in these areas. As the research shows: Vegetation has a positive effect on the retainment of water and thereby prevention of surface run-off. Second of all, water is also taken up by the leaves of a plant, known as interception (Marsh & Kaufman, 2013). The canopy of the trees intercept some of the rain, and evaporate it back into the atmosphere, before the rain has even touched the ground. Important to note is that this effect is only limited, especially in the winter when most trees and bushes dropped the leaves (Marsh & Kaufman, 2013). The leaves do have an important further function in the winter, the dead leaves form a thick layer of humus-rich soil that intercepts more rain from running-off (Marsh & Kaufman, 2013). The third way is through depression storage, which are little puddles or bumps in the soil where the water could be stored temporarily, before it is evaporated back into the atmosphere (Marsh & Kaufman, 2013). Important is the ’infiltration capacity’ of the ground, the amount of water that could infiltrate into the ground (Marsh & Kaufman, 2013). The infiltration capacity is determined by the type of vegetation, soil and slope (Marsh & Kaufman, 2013). Vegetation loosens the soil through the roots, which makes it easier for water to infiltrate. The soil is also

important, whereas water could easily infiltrate in sand, it is retarded with a soil of clay. The slope is important because steep slopes lower the potential of water to soak into the ground.

The sections above gave an illustration about the negative effects of a changing climate on cities. The most important threats for Dutch cities are the Urban Heat Island (UHI) effect and the increased chance of floods. Both the UHI and the number of floods could be prevented by integrating vegetation into the city. As mentioned in section 1.1.4, a bottom-up approach could provide a valuable solution to integrate vegetation into the city. The next section introduces the city of Arnhem, with the UHI and chance of flooding visualized in maps. Multiple bottom-up initiatives are active in the city of Arnhem to integrate vegetation in the city, specified to the local context. The initiatives are guided by the platform is (‘Arnhem Klimaatbestendig’).

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27

1.3 The city of Arnhem

The research focusses on the city of Arnhem, which is the capital of the province of Gelderland. The municipality of Arnhem already won gold in 2009 with a European competition of the greenest city of Europe (Berends, 2017). In addition, the city of Arnhem also has a special bond with nature because of its location, a 1000M2_{nature area is located against the city (de Veluwe). Arnhem has a big park near}

the central station (het Sonsbeek Park) which transforms into the Veluwe, the close location of such a great forest makes the city of Arnhem unique. Below (figure 12) is the city of Arnhem and the

surrounding areas. The municipality of Arnhem is now striving to have the greenest city centre of The Netherlands again (Arnhem Klimaat Bestendig, 2018). The perspective for 2025 is a green inclusive city (Groeninclusief Arnhem, 2015). On the one hand possibilities are created to add vegetation to the city, and on the other hand to find green solutions to improve the health, sustainability and socialization of the residents and the city (Groeninclusief Arnhem, 2015). There is a clear division of roles and a structural partnership between the municipality, other parts of the government, societal and green organisations, entrepreneurs and residents (Groeninclusief Arnhem, 2015). The municipality is actively facilitating and inviting local actors to start initiatives (Groeninclusief Arnhem, 2015). The municipality has a new role as an equal partner who thinks along with the projects, carries part of the responsibility and supports financially (Groeninclusief Arnhem, 2015). Important is to the similarities with section 2.1 and 2.1 about the new planning strategy and the Environment and Planning Act.

Figure 1211: The geographical location of Arnhem in the province Gelderland. Note the large green area (De Veluwe) directly against the city of Arnhem. Source: Stichting WerkenInGelderland, 2018

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28 Climate effects on Arnhem visualized in maps

The most important effect of climate change on Dutch cities is the Urban Heat Island (UHI) effect and the increasing chance of floods. Below are multiple maps to demonstrate the current state of the city of Arnhem.

Figure 14: Heatstress in Arnhem. The red parts are the most vulnerable parts of the city. Source: Bloei! in Arnhem, 2017 Figure 13: Heat stress in the city of Arnhem. A red colour indicates heat stress. Source: De Volkskrant, 2013

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Figure 15: The amount of petrification (number of paved areas and buildings) in the city of Arnhem. The black parts are areas of the city with a lot of paved areas and buildings. Source: Klimaateffectatlas, 2018

The effects of a changing climate on Arnhem

As could be shown above, the city of Arnhem is also struck by the effects of climate change. Especially the Urban Heat Island (UHI) is substantial in the inner centre of the city. Figure 13 and figure 14 show the heat stress in the city of Arnhem, important to compare picture 15 with these maps. The amount of paved areas and buildings is strongly correlated with the amount of heat stress in an area (the dark spots). The effects are strongly connected with each other: Figure 15 shows that the city of Arnhem is full of paved areas and buildings, which increase the Urban Heat Island, and block the water from infiltrating into the soil (figure 16). The places where the water is not able to infiltrate into the soil could be potential problem areas for flooding. An important solution to fight the effects of a changing climate on the city is through replacing paved areas with vegetation. The vegetation could cool the

Figure 12: The amount of water on the streets in centimetres. The dark blue spots are places where the water is not able to infiltrate into the soil or sewer system. These could be potential problem areas for flooding. Source: Klimaateffectatlas, 2018

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30 local atmosphere and prevents floods because water is able to infiltrate into the soil. Especially floods could be a potential problem, because the city of Arnhem knows a lot of height differences. Below are 2 more pictures of height early higher than the areas to the south (The inner centre of Arnhem). Important to note is that forests retain water (see 1.2: “How does vegetation prevent floods?”) so the water run-off is partly withheld from threatening the city. Also, important to note is that the amount of water able to infiltrate into the soil is decreasing with the height of the slopes. It is therefore difficult to make exact conclusions, but the height of Arnhem could also become an important factor because water flows from high to low, which brings Arnhem in a vulnerable position (see figure 17 and 18).

Figure 17: Height differences in the city of Arnhem and the surroundings. A red area indicates a high area. A blue colour indicates a lower part. Source: Waterschap Rijn & Ijssel, 2014

Figure 18: Height differences between Arnhem and the surroundings of Arnhem. Source: Klimaateffectatlas, 2018

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31 Summary: The threats (UHI & water nuisance) and possibilities (vegetation) combined

The translation of the legenda: Hitteplekken in de stad: Heat areas

Hoe lichter de kleur oranje, hoe minder heet de hitteplek is: The lighter the colour orange, the less heat in the area Project (idee) om Arnhem klimaatbestendig te maken: Idea to create a climate adaptive city.

Wateroverlast in de stad: Water nuisance in the city

Water in the stad: Water in the city (unable to infiltrate in the soil) Groen in de stad: vegetation in the city.

Figure 19: The negative effects of a changing climate on the city of Arnhem. Below is the legend for the specific effects. Source: Arnhem Klimaatbestendig, 2016.

How do bottom-up climate adaptive initiatives contribute to a healthy environment in the city? A research into the possibilities of using a bottom-up strategy to achieve a healthy city