Showing papers on "Urban climate published in 2013"

Government by experiment? Global cities and the governing of climate change

Abstract: In this paper, we argue for an approach that goes beyond an institutional reading of urban climate governance to engage with the ways in which government is accomplished through social and technical practices. Central to the exercise of government in this manner, we argue, are ‘climate change experiments’– purposive interventions in urban socio-technical systems designed to respond to the imperatives of mitigating and adapting to climate change in the city. Drawing on three different concepts – of governance experiments, socio-technical experiments, and strategic experiments – we first develop a framework for understanding the nature and dynamics of urban climate change experiments. We use this conceptual analysis to frame a scoping study of the global dimensions of urban climate change experimentation in a database of 627 urban climate change experiments in 100 global cities. The analysis charts when and where these experiments occur, the relationship between the social and technical aspects of experimentation and the governance of urban climate change experimentation, including the actors involved in their governing and the extent to which new political spaces for experimentation are emerging in the contemporary city. We find that experiments serve to create new forms of political space within the city, as public and private authority blur, and are primarily enacted through forms of technical intervention in infrastructure networks, drawing attention to the importance of such sites in urban climate politics. These findings point to an emerging research agenda on urban climate change experiments that needs to engage with the diversity of experimentation in different urban contexts, how they are conducted in practice and their impacts and implications for urban governance and urban life.

A survey of urban climate change experiments in 100 cities

Abstract: Cities are key sites where climate change is being addressed. Previous research has largely overlooked the multiplicity of climate change responses emerging outside formal contexts of decision-making and led by actors other than municipal governments. Moreover, existing research has largely focused on case studies of climate change mitigation in developed economies. The objective of this paper is to uncover the heterogeneous mix of actors, settings, governance arrangements and technologies involved in the governance of climate change in cities in different parts of the world. The paper focuses on urban climate change governance as a process of experimentation. Climate change experiments are presented here as interventions to try out new ideas and methods in the context of future uncertainties. They serve to understand how interventions work in practice, in new contexts where they are thought of as innovative. To study experimentation, the paper presents evidence from the analysis of a database of 627 urban climate change experiments in a sample of 100 global cities. The analysis suggests that, since 2005, experimentation is a feature of urban responses to climate change across different world regions and multiple sectors. Although experimentation does not appear to be related to particular kinds of urban economic and social conditions, some of its core features are visible. For example, experimentation tends to focus on energy. Also, both social and technical forms of experimentation are visible, but technical experimentation is more common in urban infrastructure systems. While municipal governments have a critical role in climate change experimentation, they often act alongside other actors and in a variety of forms of partnership. These findings point at experimentation as a key tool to open up new political spaces for governing climate change in the city.

Synergistic Interactions between Urban Heat Islands and Heat Waves: The Impact in Cities Is Larger than the Sum of Its Parts*

Abstract: Cities are well known to be hotter than the rural areas that surround them; this phenomenon is called the urbanheatisland.Heatwavesareexcessivelyhotperiodsduringwhichtheairtemperaturesofbothurbanand rural areas increase significantly. However,whether urban andrural temperaturesrespondin the same wayto heat waves remains a critical unanswered question. In this study, a combination of observational and modeling analyses indicates synergies between urban heat islands and heat waves. That is, not only do heat waves increase the ambient temperatures, but they also intensify the difference between urban and rural temperatures. As a result, the added heat stress in cities will be even higher than the sum of the background urban heat island effect and the heat wave effect. Results presented here also attribute this added impact of heat waves on urban areas to the lack of surface moisture in urban areas and the low wind speed associated with heat waves. Given that heat waves are projected to become more frequent and that urban populations are substantiallyincreasing,thesefindingsunderlinetheseriousheat-related healthrisksfacingurbanresidentsin the twenty-first century. Adaptation and mitigation strategies will require joint efforts to reinvent the city, allowing for more green spaces and lesser disruption of the natural water cycle.

Revisiting the urban politics of climate change

Abstract: In our 2005 paper, Rethinking Sustainable Cities, we made a case for the increasing significance of climate change in the urban politics of sustainability. Taking a multilevel governance perspective, we argued that the ‘urban’ governance of climate protection was not confined to a local arena or to the actions of the state, but rather was orchestrated through the interrelations between global, national and local actors across state/non-state boundaries. We revisit these arguments and examine their validity in the light of the rapidly changing landscape of urban responses to climate change and the growing academic literature in this field. We consider in turn: the ways in which climate change is shaping urban agendas; the utility of multilevel governance perspectives for understanding this phenomenon; and the extent to which we can identify a ‘new’ politics of urban climate change governance and its consequent implications for the development of theory and practice in this field.

Urbanization and climate change impacts on future urban flooding in Can Tho city, Vietnam

Abstract: . Urban development increases flood risk in cities due to local changes in hydrological and hydrometeorological conditions that increase flood hazard, as well as to urban concentrations that increase the vulnerability. The relationship between the increasing urban runoff and flooding due to increased imperviousness is better perceived than that between the cyclic impact of urban growth and the urban rainfall via microclimatic changes. The large-scale, global impacts due to climate variability and change could compound these risks. We present the case of a typical third world city – Can Tho (the biggest city in Mekong River Delta, Vietnam) – faced with multiple future challenges, namely: (i) the likely effect of climate change-driven sea level rise, (ii) an expected increase of river runoff due to climate change as estimated by the Vietnamese government, (iii) increased urban runoff driven by imperviousness, and (iv) enhancement of extreme rainfall due to urban growth-driven, microclimatic change (urban heat islands). A set of model simulations were used to construct future scenarios, combining these influences. Urban growth of the city was projected up to year 2100 based on historical growth patterns, using a land use simulation model (Dinamica EGO). A dynamic limited-area atmospheric model (WRF), coupled with a detailed land surface model with vegetation parameterization (Noah LSM), was employed in controlled numerical experiments to estimate the anticipated changes in extreme rainfall patterns due to urban heat island effect. Finally, a 1-D/2-D coupled urban-drainage/flooding model (SWMM-Brezo) was used to simulate storm-sewer surcharge and surface inundation to establish the increase in the flood hazard resulting from the changes. The results show that under the combined scenario of significant change in river level (due to climate-driven sea level rise and increase of flow in the Mekong) and "business as usual" urbanization, the flooding of Can Tho could increase significantly. The worst case may occur if a sea level rise of 100 cm and the flow from upstream happen together with high-development scenarios. The relative contribution of causes of flooding are significantly different at various locations; therefore, detailed research on adaptation are necessary for future investments to be effective.

The city and urban heat islands: A review of strategies to mitigate adverse effects

Abstract: Cities occupy 2% of the earth's surface but their inhabitants consume 75% of the world's energy resources. Under certain conditions, the heat from solar radiation and different urban activities can make city temperatures rise in certain areas, simply because of the way in which a city is structured. This effect is known as the urban heat island (UHI). This article provides a review of recent research on the urban heat island as well as of the strategies that can be applied to mitigate its adverse effects. Such strategies can be applied in the project design phase of urban planning and thus directly affect city temperatures on a local scale. The elements analyzed in this paper include green spaces, trees, albedo, pavement surfaces, vegetation, as well as building types and materials. The discussion of this research clearly reflects the impact of urban morphology on local temperatures and how urban design can be modified to reduce energy consumption and CO2 emissions into the atmosphere. This study is useful for professionals who are responsible for decision-making during the design phase of urban planning.

An urbanization bomb? Population growth and social disorder in cities

Abstract: For the first time in history, the majority of the world population now lives in cities. Global urbanization will continue at high speed; the world's urban population is projected to increase by more than 3 billion people between 2010 and 2050. Some of this increase will be the result of high urban fertility rates and reclassification of rural land into urban areas, but a significant portion of future urbanization will be caused by rural-to-urban migration. This migration is expected to be particularly prevalent in countries and regions most affected by the changing climate. While urban populations generally enjoy a higher quality of life, many cities in the developing world have large slums with populations that are largely excluded from access to resources, jobs, and public services. In the environmental security literature, great rural resource scarcity, causing rural to urban migration, is seen as an important source of violent conflict. This study investigates how population growth affects patterns of public unrest in urban centers within the context of crucial intervening factors like democracy, poverty, economic shocks. It utilizes a newly collected event dataset of urban social disturbance covering 55 major cities in Asia and Sub-Saharan Africa since 1960. The empirical analysis provides little support for the notion that high and increasing urban population pressure leads to a higher risk or frequency of social disorder. Instead, we find that urban disorder is primarily associated with a lack of consistent political institutions, economic shocks, and ongoing civil conflict.

Watering our cities The capacity for Water Sensitive Urban Design to support urban cooling and improve human thermal comfort in the Australian context

Abstract: Urban drainage infrastructure is generally designed to rapidly export stormwater away from the urban environment to minimize flood risk created by extensive impervious surface cover. This deficit i...

Futures of global urban expansion: uncertainties and implications for biodiversity conservation

Abstract: Urbanization will place significant pressures on biodiversity across the world. However, there are large uncertainties in the amount and location of future urbanization, particularly urban land expansion. Here, we present a global analysis of urban extent circa 2000 and probabilistic forecasts of urban expansion for 2030 near protected areas and in biodiversity hotspots. We estimate that the amount of urban land within 50 km of all protected area boundaries will increase from 450 000 km2 circa 2000 to 1440 000 ± 65 000 km2 in 2030. Our analysis shows that protected areas around the world will experience significant increases in urban land within 50 km of their boundaries. China will experience the largest increase in urban land near protected areas with 304 000 ± 33 000 km2 of new urban land to be developed within 50 km of protected area boundaries. The largest urban expansion in biodiversity hotspots, over 100 000 ± 25 000 km2, is forecasted to occur in South America. Uncertainties in the forecasts of the amount and location of urban land expansion reflect uncertainties in their underlying drivers including urban population and economic growth. The forecasts point to the need to reconcile urban development and biodiversity conservation strategies.

Does Size Matter? Scaling of CO2 Emissions and U.S. Urban Areas

Abstract: Urban areas consume more than 66% of the world’s energy and generate more than 70% of global greenhouse gas emissions. With the world’s population expected to reach 10 billion by 2100, nearly 90% of whom will live in urban areas, a critical question for planetary sustainability is how the size of cities affects energy use and carbon dioxide (CO2) emissions. Are larger cities more energy and emissions efficient than smaller ones? Do larger cities exhibit gains from economies of scale with regard to emissions? Here we examine the relationship between city size and CO2 emissions for U.S. metropolitan areas using a production accounting allocation of emissions. We find that for the time period of 1999–2008, CO2 emissions scale proportionally with urban population size. Contrary to theoretical expectations, larger cities are not more emissions efficient than smaller ones.

The urban weather generator

Abstract: The increase in air temperature produced by urbanization, a phenomenon known as the urban heat island (UHI) effect, is often neglected in current building energy simulation practices. The UHI effect can have an impact on the energy consumption of buildings, especially those with low internal heat gains or with an inherent close interaction with the outdoor environment (e.g. naturally-ventilated buildings). This paper presents an urban weather generator (UWG) to calculate air temperatures inside urban canyons from measurements at an operational weather station located in an open area outside a city. The model can be used alone or integrated into existing programmes in order to account for the UHI effect in building energy simulations. The UWG is evaluated against field data from Basel (Switzerland) and Toulouse (France). The error of UWG predictions stays within the range of air temperature variability observed in different locations of the same urban area.

Sensors and the city : a review of urban meteorological networks

Abstract: The heterogeneous nature of urban environments means that atmospheric research ideally requires a dense network of sensors to adequately resolve the local climate. With recent advances in sensor technology, a number of urban meteorological networks now exist with a range of research or operational objectives. This article reviews and assesses the current status of urban meteorological networks, by examining the fundamental scientific and logistical issues related to these networks. The article concludes by making recommendations for future deployments based on the challenges encountered by existing networks, including the need for better reporting and documentation of network characteristics, standardized approaches and guidelines, along with the need to overcome financial barriers via collaborative relationships in order to establish the long-term urban networks essential for advancing urban climate research. Copyright © 2013 Royal Meteorological Society

Modeling the influence of open water surfaces on the summertime temperature and thermal comfort in the city

Abstract: [1] Due to the combination of rapid global urbanization and climate change, urban climate issues are becoming relatively more important and are gaining interest. Compared to rural areas, the temperature in cities is higher (the urban heat island effect) due to the modifications in the surface radiation and energy balances. This study hypothesizes that the urban heat island can be mitigated by introducing open surface water in urban design. In order to test this, we use the WRF mesoscale meteorological model in which an idealized circular city is designed. Herein, the surface water cover, its size, spatial configuration, and temperature are varied. Model results indicate that the cooling effect of water bodies depends nonlinearly on the fractional water cover, size, and distribution of individual lakes within the city with respect to wind direction. Relatively large lakes show a high temperature effect close to their edges and in downwind areas. Several smaller lakes equally distributed within the urban area have a smaller temperature effect, but influence a larger area of the city. Evaporation from open water bodies may lower the temperature, but on the other hand also increases the humidity, which dampens the positive effect on thermal comfort. In addition, when the water is warmer than the air temperature (during autumn or night), the water body has an adverse effect on thermal comfort. In those cases, the water body eventually limits the cooling and thermal comfort in the surrounding city, and thus diverges from the original intention of the intervention.

FORUM: Sharing or sparing? How should we grow the world's cities?

Abstract: Summary 1. There has long been a debate amongst conservation biologists about how agricultural land use should be distributed spatially. Advocates of land sparing argue that high-intensity food production on small units of land will conserve more natural habitat than low-intensity farming spread across larger areas. Others argue that less intensive production over a greater area of land will reduce the overall load of human stressors upon ecosystems. 2. Although agricultural and urban systems have traditionally been considered as different fields of research, there are strong parallels between the two landscapes in the patterns of their spatial configuration and the trade-offs associated with their development. Continued and rapid urbanization, with associated losses in vegetation, highlights the need for a uniting spatial framework to assess the ecological impacts of urbanization. Here, we apply some of the thinking emerging from the agricultural land-sparing debate to urbanization, review the similarities and differences between the two systems and set out a research agenda. 3. Intensification of urban systems to increase housing density leads to buildings being interspersed with small tracts of natural or semi-natural habitat patches (e.g. forest patches, parks). Urban extensification, on the other hand, is characterized by sprawling suburbanization with less concentrated, more distributed green space, often predominantly in the form of backyard or streetscape vegetation. We argue that regional scale analyses are urgently needed to determine which of these patterns of urban growth has a lower overall impact on biodiversity and to explore the geographical and taxonomic variation in the most ecologically appropriate city layout. 4. Synthesis and applications. The spatial pattern of urban development will affect biodiversity conservation within and beyond a city’s borders. We chart the early progress of empirical work on the land-sparing debate in an urban context and suggest that to yield development patterns that minimize overall ecological impact, urban planners must work at the scale of at least the entire city rather than on a case-by-case basis.

What is the purpose of urban climate resilience? Implications for addressing poverty and vulnerability

Abstract: This paper considers how development policy concerns for poverty reduction and social justice can be accommodated in emerging theories and practice on urban resilience and adaptation in response to climate change. There is growing interest in applying resilience to address the challenges of urban climate change. The application of resilience theory has considerable potential for furthering our understanding of the particulars of urban climate vulnerability with its emphasis on complex systems that are increasingly important to urban life. But there are also significant risks. Resilience theory does not adequately address critical issues of power, voice and equity. Moreover, much of the uptake of resilience is as a buzzword rather than a conceptual framework. As such, the discourse of resilience has connotations that can run counter to interests of poverty reduction. Drawing on experience in Asia, the authors argue for a critical application of resilience, with special attention to concerns of resilience for and by whom.

Maintaining Climate Change Experiments: Urban Political Ecology and the Everyday Reconfiguration of Urban Infrastructure

Abstract: Climate change governance is increasingly being conducted through urban climate change experiments, purposive interventions that seek to reconfigure urban sociotechnical systems to achieve low-carbon and resilient cities. In examining how experiments take effect, we suggest that we need to understand not only how they are made and assembled, but also how they are maintained within specific urban contexts. Drawing on literatures from urban political ecology and the specific debate on urban repair and maintenance, this article examines maintenance in two case studies of climate change experiments in housing in Bangalore (India) and Monterrey (Mexico). We find that maintenance is a crucial process through which not only urban obduracy is preserved, but also the novel and innovative character of the experiment is asserted and reproduced. The process of ‘maintaining’ experiments is a precarious one, which requires a continuous external input in terms of remaking the experiment materially and discursively. This process causes further reconfigurations beyond the experiment, changing the patterns of responsibility attribution and acceptability that configure the urban fabric.

Justice in urban climate change adaptation: Criteria and application to Delhi

Abstract: Cities around the world are increasingly developing plans to adapt to the consequences of climate change. These plans will have important consequences for urban populations because they are likely to reshape and reconfigure urban infrastructures, services, and decision making processes. It is critical that these adaptation plans are developed in a way that is just. Criteria was developed that can be used to assess justice in adaptation so that the processes, priorities, and impacts address the needs of the most vulnerable urban populations. Further, mechanisms are outlined that have been proposed as responsible for producing urban injustice. The justice criteria are applied to the case of adaptation planning in Delhi and the extent to which poor and informal populations are included and affected by this planning. The analysis shows that adaptation planning in Delhi does not meet the justice criteria in part because of a lack of capacity and the political economy of poverty in the city. The criteria for justice and mechanisms of injustice offer an important step toward developing a greater understanding of not only whether city-level adaptation planning is just, but also why it is or is not.

Networked Urban Climate Governance: Neighborhood-Scale Residential Solar Energy Systems and the Example of Solarize Portland:

Abstract: With this paper I investigate the role of civil society groups in speeding the urban adoption of green technologies (in particular, renewable energy systems) by creating economic niches, and catalyzing market transformations. I focus on a qualitative case study of Solarize Portland, a community-managed solar energy program that has transformed the local and regional market for solar energy in Portland, OR. This case study is analyzed through the lens of recent theories of public participation that emphasize the multiplicity and complexity of participatory processes in practice. I conclude that�thanks to their flexibility, risk tolerance, and locally embedded understanding of technological change�civil society groups have the capacity to design and implement significant urban sustainability projects. They achieve this by creating niches within the urban landscape that allow local small and medium-sized enterprises to develop and refine their businesses practices; by coordinating novel partnerships between state, community, and private-level actors; and by grounding technological change in the broader social networks that give them meaning and momentum. These findings speak directly to the way that cities approach the complex sociotechnical transitions involved in reshaping urban infrastructure to respond to the challenge of climate change.

Assessment of the climate preparedness of 30 urban areas in the UK

Abstract: Cities are increasingly aware of the need to mitigate greenhouse gas emissions and adapt to changes in weather patterns leading to the production of urban climate change plans. The few existing systematic studies of these plans have focused on either adaptation or mitigation issues, and are typically based on surveys completed by city officials rather than analysis of documented evidence. To gain insight into the status of adaptation and mitigation action across the UK, climate change documents from 30 urban areas (representing ~28 % of the UK’s population) were analysed. An Urban Climate Change Preparedness Score, which could be applied to other urban areas outside the UK, has been devised for comparative analysis. This analysis characterizes progress against (i) Assessment, (ii) Planning, (iii) Action, and (iv) Monitoring, for both adaptation and mitigation. The Preparedness Score allows a quantitative comparison of climate change strategies across the urban areas analysed. This methodology can be transferred to other countries and makes an international comparison of urban areas and their climate change adaptation and mitigation plans possible. We found that all areas acknowledge climate change being a threat and that adaptation and mitigation planning and action is required. However, two urban areas did not have official adaptation or mitigation plans. Typically, mitigation activities across all cities were more advanced than adaptation plans. Emissions reduction targets ranged from 10 %–80 % with differing baselines, timeframes and scopes, for defining and meeting these targets. Similar variability was observed across adaptation plans. Several reasons for these differences are considered, but particularly notable is that a combination of incentives and regulation seem to stimulate more comprehensive strategies and action in many urban areas.