İstanbul’da Kentleşmenin İklim Değişikliğine Uyum Çerçevesinde Değerlendirilmesi

Abstract

İklim değişikliğine uyum, bir çok uluslararası organizasyon ve Avrupa Birliği (AB) kurumlarının gündemlerinde yer alan ve günümüzde önemi gitgide artan bir konudur. Özellikle İstanbul gibi gelişmekte olan ve sürekli değişen dinamiklere sahip kentlerde, hızlı kentleşmenin, kurumsal ve yasal zemindeki boşlukların arazi kullanımı ve arazi örtüsü (AKAÖ) üzerinde yarattığı hassasiyetlerin yanısıra, iklim değişikliğine bağlı sıcaklık artışı ve yağış miktarındaki değişikliklerin sonucunda oluşan taşkın, sıcak hava dalgası ve kuraklık gibi etkilerin, bu mevcut hassasiyetleri daha da arttırması beklenmektedir. Kentleşme ve iklim değişikliğine bağlı bu hassasiyetler, gelecekte yaşam kalitesi ve sürdürülebilir kalkınmayı sağlamaya yönelik hedefler önünde engel oluşturabilir. İstanbul’un kentsel kalkınma dinamikleri; kentin başlıca habitatlarını oluşturan su kaynakları, ormanlar, sulak alanlar, makilik alanlar ve kıyı alanları gibi biyolojik çeşitlilik ve ekolojik birimlerin sürekliliğinin sağlanmasında önemli role sahiptir. (Özhatay et.al. 2005, Tezer 2005, Tezer 2008). Bu araştırmanın amacı, İstanbul’da kentleşme ve iklim değişikliğinin AKAÖ üzerinde yaratması beklenen hassasiyetleri gidermek için önemli araçlardan biri olan iklim değişikliği ile uyumlu mekansal planlama yaklaşımını geliştirerek, sürdürülebilir kalkınmaya katkı sağlamaktır. İstanbul’da iklim değişikliğinin AKAÖ üzerindeki olası etkilerinin tanımlanmasında iklim değişikliği senaryolarından faydalanılmıştır (Agora, 2011). Kentleşme sonucunda artan ısı adası etkisinin, iklim değişikliğinin en önemli etkilerinden sıcaklık artışını daha da arttırabileceği yönünde İstanbul’da yapı düzeyinin de dahil edildiği mekansal analizler bu tezin önemli çıktılarındandır. AKAÖ’ye yönelik hassasiyetler, iklim değişikliği, ısı adası etkisinin belirlenmesine yönelik yapılan analiz sonuçları ile mekansal ve yasal dinamiklere göre geliştirilen AKAÖ senaryoları kullanılarak tanımlanmaya çalışılmıştır. Bu hassasiyetler, iklim değişikliği ile uyumlu sürdürülebilirlik göstergeleri ile ölçülmeye çalışılmış, iklim değişikliğine hassas AKAÖ’nün ve iklim değişikliğine uyumda ön plana çıkan AKAÖ’nün belirlenmesi konusunda aktörlerin görüşlerinden faydalanılmıştır. Bu değerlendirmeden yola çıkılarak İstanbul’da iklim değişikliğine karşı hassas olan öncelikli AKAÖ ve iklim değişikliğine uyumda öncelikli öneme sahip AKAÖ tanımlanmıştır. Sonuç olarak iklim değişikliği ile uyumlu mekansal planlamanın bileşenleri tanımlanarak, iklim değişikliğine uyumda öne çıkan planlama araçlarından bahsedilmiştir. Bu planlama araçları çerçevesinden yapılan GZFT (SWOT) analizi ile Türkiye ve İstanbul’un mevcut durumu, potansiyeller ve engeller açıklanmaya çalışılmıştır. Son olarak iklim değişikliği ile uyumlu bir kentleşme için mevcut mevzuatın değerlendirmesi yapılarak, öneriler geliştirilmiştir. Tez kapsamında kullanılan bu yaklaşımın İstanbul’da ve diğer hızla gelişmekte olan yerleşmelerde, iklim değişikliği ile uyumlu kalkınma politikalarının geliştirilmesinde rasyonel bir araç olabileceği düşünülmektedir.

Climate change adaptation is a rising global issue and has already placed in most of the transnational organizations’ and European Union institutions’ agendas. Especially in developing and ever-dynamic cities like Istanbul, climate impacts like floods, heat waves and droughts due to the rise in temperatures and change in precipitation are expected to create new vulnerabilities on land cover and land uses (LCLUs) besides the pressure of rapid urbanization, institutional and legislative gaps (Hunt et.al, 2011, UN, 2011, IPCC, 2007). These urbanization and climate based vulnerabilities may affect human well-being and interfere reaching sustainable development goal in the future. Climate change strategies and spatial planning have a strong relationship as they may affect human well-being and urban morphology (Zhao et.al., 2010). Change in LCLU especially as a result of urbanisation, is one of the main reasons for increasing the green house gas (GHG) emissions (Tan et al., 2010). Both climate and LCLU change may create serious challenges on ecosystems (EPA 2009). Evaluating the future LCLU with projected changes in primary climate parameters (e.g. temperature and precipitation) can assist on better understanding of the vulnerabilities on LCLU and ESs. Istanbul has a unique geographical location for biological diversity when compared with other settlements in the region. The urban development dynamics of the region play a significant role in the well-being of ecological units and biological diversity of the Istanbul Metropolitan Area (Özhatay et al., 2005; Tezer, 2005; Tezer, 2008). Istanbul is a unique example among rapidly growing metropolitan cities that covers 5344 km2 and has a population over 14 million with an increase of 26%, between 2000 and 2013 (TÜIK, 2013). The urbanisation ratio is around 99% (TUİK, 2013) and it has the third highest GDP among 78 OECD metro regions (OECD, 2008b). Istanbul geographically combines two continents and the climatic regions of Mediterranean and Black Sea which have also very significant role in the natural structure of the city. The existing pressure of increasing urbanisation and population growth in Istanbul are expected to increase in the near future. Climate change is a new challenge for the metropolitan area and its impacts may increase with the pressures of urbanisation. This study aims to overcome the possible vulnerabilities of urbanization and climate change impacts on LCLU of Istanbul by developing a climate integrated urban planning as a major tool in order to support sustainable develoment. Besides the evaluation of the literature reviews made for understanding possible impact of climate change on LCLU (FAO, 2013; EEA, 2012; EPA, 2012; Fagundez, 2012), climate change scenarios (by using the results of the MDG-F 1680 project) and LCLU scenarios (adapted from Shearer et al., 2009) were developed to understand the possible impact of future built-up areas and climate change on LCLU, the importance of LCLU in adapting to climate change, and possible policies. Analysis to determine the interaction between urbanization and heat island effect in Istanbul, have a particular importance in this thesis and their results are used for developing a climate change adapted spatial planning framework and related strategies. Actor opinion is used to define and to verify the existing and future vulnerabilities of LCLU and to determine the important LCLU for adaptation to climate change in Istanbul. Finally, an overall comprehensive evaluation is done by developing climate change adapted sustainability indicators based on LCLU. There are three main spatial analysis in this thesis: • Climate change scenarios: Climate change scenarios (A2 ECHAMP 5) are used in this thesis to understand the possible future climatic conditions of Istanbul and their impact on LCLU. According to A2 emissions scenario developed in this study (Agora, 2011), the average annual temperature seems to increase around 0.5 C° until 2030-2039, 2 C° until 2060-2069 and 3.5 C° until 2090-2099. This increase is expected to be more significant after 2060’s. Increase of 3.5 C° until 2100 is the same value with the predictions of IPCC global climate change scenarios. The increase in temperature seems to be worse in summer period (4.5 C°) until 2099. According to these scenarios, spatial distribution of increase in temperature seems to be homogeneous while change in precipitation doesn’t. The impacts of climate change on LCLU like forest, water surfaces, agriculture, built-up areas are important to be addressed for further evaluations. • Analysis to determine heat island effect in Istanbul: In order to address the impact of urbanisation on local climate; spatial analyses including building’s total surface, urban sprawl and satellite thermal views (LANDSAT 7 ETM), together with minimum summer period average temperature data are assessed. It is important to understand that; urbanization may alter the temperature which has already risen by climate change. The results are used for developing the main framework of climate change adapted spatial planning. • LCLU scenarios: The existing drivers, which may change LCLU of Istanbul can be categorized as rapid spatial expansion due to urbanization, population growth, gaps in regulations, unplanned urbanization and rapidly emerging economic activities. There are several things that increase the uncertainties in Istanbul’s future LCLU. These can be summarised as follows; • Istanbul is open to spatial investments with high speculations as the city is the growing economic engine of Turkey, • Spatial investments may be changed or postponed in a very short period of time, • The growing population and economy of Istanbul have been driven by sudden, top-down decisions, which may cause new uncertainties and disrupt sustainable development, • Even though local government has right to prepare and approve province-wide spatial development plans, central government has a broader authority to make spatial investments that may influence and/or change the development decisions of this plan. These ever changing dynamics complicate the planning process done with existing data. So scenario analysis is needed to understand the future situation and decrease uncertainties. It appears as an efficient tool for the planning process that facilitates creating future data, analysing the future situation and understanding the possible vulnerabilities. The LCLU scenario methodology is adapted from the studies of Schwartz (1991 in Shearer et al, 2009) and Bryan et al. (2011) in Lower Murray, Australia. A new scenario construction process adapted from these two studies is developed as shown below; • Defining the issues and/or decisions that may change the LCLU of Istanbul, • Addressing driving forces or trends, • Joining the similar driving forces and ranking by importance, • Defining the main two drivers of Istanbul in X and Y axis, • Analysing four different potential scenarios according to their responses to pre-defined policies, • Scoring the scenarios and giving names according to their features, • Defining the spatial criteria for each scenario, • Implication in the ARC-GIS interface, • Analysing the future impact of urbanization on natural LCLU, • Evaluation of these scenarios and developing spatial strategies. Both studies emphasise that related stakeholders and decision makers should be included at each step of the scenario construction process. In addition, a continuous monitoring process should be integrated to intervene and re-assess the process in case of necessity. Future LCLU in Istanbul is addressed by existing LCLU trends, present plan decisions, and large-scale investments based on the decisions of the Council of Ministers and legal reports. In order to determine the priority of the LCLU’s, to combat climate change, and/or take precautions to increase their resilience and to verify the purpose; an actor opinion procedure is taken into consideration. The actor opinion procedure was conducted in a workshop organised by the TUBITAK 110K350 Project. Through this survey, an attempt was made to determine the interaction between ecosystem services, LCLU, climate change and sustainable urbanization. A scale rating was used in questions to facilitate the procedure and prioritize the topics. A similar methodology was used to determine the priorities of LCLU, ESs (Koschke et al., 2012), and location decisions (Awasthi et al., 2011) by using statistical analysis such as multi criteria analysis. These actors consisted in 39 participants from local municipalities, the metropolitan municipality, planning and environmental associations, NGO’s such as Regional Environmental Center Turkey (REC) and The Turkish Foundation for Combating Soil Erosion, for Reforestation and the Protection of Natural Habitats (TEMA), and representatives of related ministries. The results of this analysis, as well as the climate change, LCLU scenarios and heat island effect analysis are evaluated together by climate change adapted sustainability indicators for a final conclusion to address the vulnerable LCLU and LCLU which are important for climate change adaptation and mitigation. As a result, a spatial planning framework that is climate change adapted is tried to be addressed as a key tool. Under this framework, planning tools considering climate change adaptive policies are developed and proposed for filling the gaps in existing regulations in order to achieve a climate resilient, sustainable development in Istanbul. The framework used in this thesis can be a rational key tool to implement climate adaptive policies for development in Istanbul and can be used for other rapidly developing settlements.