Urban Climate Adaptation Research Articles

Recognizing the Role of Forests in Urban Climate Mitigation and Adaptation: State of the Art, Lessons Learned, and the Way Forward

Recognizing the Role of Forests in Urban Climate Mitigation and Adaptation: State of the Art, Lessons Learned, and the Way Forward

Entrepreneurial Strategies to Address Rural-Urban Climate-Induced Vulnerabilities: Assessing Adaptation and Innovation Measures in Dhaka, Bangladesh

Climate change amplifies social, political, economic, infrastructural and environmental challenges in many Global South cities, and perhaps no city is more vulnerable than Bangladesh’s capital of Dhaka. Climate-induced rural–urban migration is a profound concern, and Dhaka’s political leaders have embraced technology-based innovation as one solution pathway. This article explores the societal impact of Dhaka’s innovation environment strategies for climate change adaptation and mitigation. Employing a case study qualitative methodology, our three findings expand knowledge about innovation for urban climate adaptation and mitigation as understood by Dhaka-based entrepreneurs. First, the most effective innovations were not the most technologically advanced, but those with the highest degree of participant ownership. Second, gaps between recipient, corporate and governmental understandings of effective mitigation and adaptation harmed projects were driven by different definitions of risk and competing understandings of vulnerability. Third, even the most technical climate adaptation measures were inherently political in their application. We discuss how to better position urban climate innovation infrastructures in Bangladesh and beyond, including developing a better recognition of innovation lifecycles for urban climate adaptation and widening our definitions of “innovation” to better incorporate more effective and inclusive climate adaptation solutions.

Awareness of urban climate adaptation strategies –an international overview

Problems caused by urban climate phenomena such as urban heat island intensification, nuisance winds, or the lack of ventilation, are a growing concern with urban population growth and aging infrastructure. While many possible solutions are known, effective adaptation strategies have been insufficiently implemented to ameliorate urban climate problems. Reasons for this ‘implementation gap’ such as the level of awareness about implementable solutions have received little attention in the literature. An important question thus remains unanswered: what do different urban actors (citizens; politicians; urban planners and designers; and urban climate experts) who shape the urban environment and thus its climate, know about urban climate adaptation measures? We conducted a pilot study using semi-structured interviews with specialists in the field of urban sustainability related to urban planning and climate in ten countries worldwide. Interview results indicated that awareness of adaptation measures differs between countries, but even more so between different actor groups. Citizens and politicians are less aware than urban planners or designers and urban climate experts. Awareness raising should involve media campaigns, further education and display of good practice. Politicians should work on better laws and their enforcement and urban climate experts on good knowledge communication.

The motley drivers of heat and cold exposure in 21st century US cities

We use a suite of decadal-length regional climate simulations to quantify potential changes in population-weighted heat and cold exposure in 47 US metropolitan regions during the 21st century. Our results show that population-weighted exposure to locally defined extreme heat (i.e., "population heat exposure") would increase by a factor of 12.7-29.5 under a high-intensity greenhouse gas (GHG) emissions and urban development pathway. Additionally, end-of-century population cold exposure is projected to rise by a factor of 1.3-2.2, relative to start-of-century population cold exposure. We identify specific metropolitan regions in which population heat exposure would increase most markedly and characterize the relative significance of various drivers responsible for this increase. The largest absolute changes in population heat exposure during the 21st century are projected to occur in major US metropolitan regions like New York City (NY), Los Angeles (CA), Atlanta (GA), and Washington DC. The largest relative changes in population heat exposure (i.e., changes relative to start-of-century) are projected to occur in rapidly growing cities across the US Sunbelt, for example Orlando (FL), Austin (TX), Miami (FL), and Atlanta. The surge in population heat exposure across the Sunbelt is driven by concurrent GHG-induced warming and population growth which, in tandem, could strongly compound population heat exposure. Our simulations provide initial guidance to inform the prioritization of urban climate adaptation measures and policy.

The uptake of new concepts in urban greening: Insights from Poland

The idea of nature having multiple benefits for urban management and planning is gaining prominence alongside the rise of climate change awareness. It is expressed through concepts such as nature-based solutions (NbS), ecosystem-based adaptation (EbA), and blue-green infrastructure (BGI). Despite their popularity in the international arena, relatively little is known about how these concepts are used and interpreted at the local level, which has implications for policy formulation and actions. This paper examined both direct and indirect references to these concepts, as well as the reasons for their potential omission. By analysing policy documents and interviews with practitioners and activists from four Polish cities (Gdansk, Krakow, Warsaw, Wroclaw), it discussed the uneven and ambivalent uptake of concepts in the urban green and blue space (UGBS) governance. While the reluctance to use new terminology was often explained by accessibility and efficiency concerns, it also revealed some conceptual confusion. The contribution of this study is twofold: 1) providing a more nuanced understanding of the conceptual ambiguity surrounding the NbS, EbA and BGI concepts and the gap between international policy rhetorics and local interpretation; 2) expanding the geography of research on urban climate adaptation and urban green spaces which tends to overlook the countries of Central and Eastern Europe.

Material Climate Justice: Connecting Social Equity and Climate Risk in Urban Climate Adaptation

Climate reports underscore the differential impact of climate change risks for marginalized communities— women, people of color, indigenous communities, the disabled, and socioeconomically disadvantaged populations—and the need to recognize and address inequities in climate adaptation processes. To date, scholarship on climate adaptation in organization and management scholarship focuses on firm-level and empirical work has failed to account for the complexity and materiality of socio-ecological systems, historical processes that structure inequity, and the agency of actors within adaptation processes. To address this, we develop a material climate justice framework by extending conceptual links between risk, material feminism, and justice. The material climate justice lens combines climate justice (CJ) insights about political economic processes that distribute risks and rewards in the urban context and the materiality of differentially embodied exposures to risks, resources, and political advantages. We describe the ways representatives of marginalized groups practice agency in climate adaptation processes that are primarily being driven by government agencies in consultation with business, academic, and consulting groups. Findings suggest that representatives of marginalized populations engage in sub-processes to impact climate adaptation that expand notions of climate risk to include embodied experience connected to resources, representation, histories, place and future embodied experiences.

Planning for cooler cities: a plan quality evaluation for Urban Heat Island consideration

ABSTRACT City strategic plans and enabling policies provide a framework for and inform future development across multiple scales. An exemplar city strategic plan will be one based on evidence, enabled by complementary policy outcomes, and built on the knowledge of the existing landscape. This study evaluated the plan quality of eighteen metropolitan strategic plans for city members in the 100 Resilient Cities initiative. A protocol was developed containing thirty-two indicators to assess plans capacity to act as a strategic planning tool to develop, analyse and implement strategies for the Urban Heat Island (UHI) and climate change mitigation and adaptation. The evaluation indicated that strategies addressing the UHI are rarely included in metropolitan plans. Strategic plans showed a lack of evidence-base to inform the potential actions. Urban warming is often linked to extreme weather events anticipated under climate change, not the UHI as a systemic and increasing phenomenon. We recommend that the pathway to addressing UHI mitigation and adaptation may lie in its nexus to aspects of climate change that concurrently can serve to support liveable and resilient cities.

Modeling the spatial relation between urban morphology, land surface temperature and urban energy demand

Considering climate change and energy resource depletion under rapid urbanization trends in the urban environment, the relation between land-use, climate change, and urban energy demand is gaining attention. However, a limited number of studies are focusing on the effect of microclimate change, and more specifically, temperature change on energy demand at an urban scale. This study includes empirical spatial and temporal modeling to identify how urban morphology indicators (UMIs), land surface temperature (LST), and neighboring land-use compositions affect urban energy demand using an extensive data set for the case study of Eindhoven, the Netherlands. For this purpose, the ordinary least square regression (OLS) and geographically weighted regression (GWR) models are employed. The results show, there is a significant spatial relation between UMIs, neighboring land-use compositions, and urban energy demand. Furthermore, the impact of dwelling types on urban energy demand is discussed. The results can be applied to sustainable urban planning targeting energy reduction, climate adaptation, and help local authorities for implementing energy management strategies.

Revealing urban climate through animated visualizations

Climate change is intensifying urban climate problems and the design of public and private spaces should take this into account. However, the public often does not recognize these problems due to perceptual barriers. The hypothesis of this paper is that such perceptual barriers can be overcome through ‘climate revelatory visualizations’ that communicate the problems and solutions in an understandable way and can nudge parties into taking action. We created and tested several photorealistic animated visualization styles. The results indicate that urban climate problems and adaptation measures should be presented in photorealistic animations with graphic overlays to overcome perceptual barriers. The climate revelatory visualizations should frame climate adaptation positively, and feature the everyday environments of the target audience. Visualizations that reveal current situations, specifically the risks of particular climate problems, prove to have a warning function, whereas visualizations that reveal adaptation measures can motivate citizens and urban designers to take adaptation action.

Evaluating Responses of Temperature Regulating Service to Landscape Pattern Based on ‘Source-Sink’ Theory

Thermal remote sensing provides a method to describe spatial heterogeneity of the “urban heat island” effect and to evaluate the function of temperature regulation. Rapid urbanization and heatwave events with increasing frequencies need a quantitative analysis on the supply and demand for an urban temperature regulating service, which is a gap in urban heat island (UHI) studies in rapidly urbanizing cities. In order to study the quantitative relationship between landscape metrics (including area index and shape index) and temperature regulating service, this study applied a temperature regulating service in an urban thermal environment study based on the “source–sink” landscape theory in western Shenzhen in different periods. The identification of source and sink landscapes is based on the spatial relationship of unusual surface features derived from Landsat-5 and -8 and the consideration of the temperature difference. We found that the source landscapes at different periods provide temperature regulating services for different distances, which directly lead to the difference between the theoretical service value based on the Alternative Cost Method and the actual service value considering demand, changing in the same trend. The results show that the supply distance of temperature regulating services in 2005, 2010, and 2013 is 150 m, 180 m, and 210 m, respectively. The temperature regulating service value is 3.043, 3.273, and 4.308 billion yuan in 2005, 2010, and 2013, which is lower than the estimation value without considering supply and demand (16.638, 23.728, and 37.495 billion yuan, respectively). The value of the temperature regulating service has a positive correlation with the increase of the patch area index. With the gradual complexity of the shape, the service value increases first and then decreases. Moreover, the landscapes with the smallest shape index and area index have the shortest distance for service supplying. The assessment of the temperature regulating service needs to consider the presence of demand landscapes. Furthermore, the interaction of landscapes under different conditions requires further consideration. The setting of the cooling landscape shape and area for mitigating the “urban heat island” effect can provide references to urban planners and policymakers in the practice of urban climate adaptation and regulation.

Potential Impacts of Future Urbanization and Sea Level Rise on Florida's Natural Resources

Abstract As urban development continues to encroach into natural systems, these ecosystems experience increasing degradation to their form and function. Changing climatic conditions further compound the losses in biodiversity and ecosystem function. The state of Florida is known for its biodiversity but has experienced declines in species populations and habitats because of urbanization and sea level rise. Because Florida benefits from a multibillion-dollar income from natural resources tourism, these declines challenge the state's economy. In this study, we assessed the potential future impacts of urbanization and sea level rise on a suite of conservation targets that have been set for the state. We developed six scenarios of all combinations of intermediate and high sea level rise paired with two types of urbanization, sprawling and compact, in both 2040 and 2070 to examine the potential future threats to conservation targets in High Pine and Scrub, Coastal Uplands, and Freshwater Aquatics ecosystems. Our results show projected decreases in extent and area of these priority ecosystems into the future. Under Florida's current trends in urbanization practices, projections indicate a greater impact on conservation targets than if sprawl reduction practices are implemented. Projections indicate that Coastal Uplands will experience the greatest loss in area, at up to 47%. Conservation-focused urban planning and climate adaptation strategies can help protect Florida's natural resources with benefits to Florida's tourism economy as well as critical ecosystem functions and services such as coastal flood protection and storm surge risk reduction.

Does mitigation shape adaptation? The urban climate mitigation-adaptation nexus

ABSTRACT Existing research has increasingly identified synergies and trade-offs between urban climate change mitigation and adaptation policies. There is a gap, however, in our knowledge of the extent to which urban climate change mitigation efforts affect the adoption of adaptation policies. Analysing the presence of different levels of climate change mitigation efforts in European cities, while also considering local climate risks and national adaptation mandates, our results show a positive and significant correlation between mitigation and adaptation policies. This is partly a result of the perceptions and discourses linking global and local climate risks, and partly a consequence of the co-benefits of the two activities at the local level, which enable cities to piggyback on their prior mitigation efforts when adopting adaptation policies. A conceptual ‘mitigation-adaptation nexus’ governance framework is adopted to improve the current synergy versus conflict debate. Multilevel logit regression analyses of 261 European cities, controlling for both city- and country-level factors, suggest that adaptation is positively influenced in cities with mitigation action policies with monitoring systems, rather than mere mitigation commitments. We also find that national mandates drive local adoption of adaptation policies. Key policy insights The mitigation-adaptation nexus approach enables cities to regard climate change policies not as single-dimensional, but as comprehensive capacity building efforts. Cities committed to actual progress on mitigation policy (i.e. with a monitoring system in place) are more likely to adopt adaptation policies. Cities are driven to join municipal adaptation networks on the basis of their established mitigation policies rather than local climate risk profiles. National adaptation mandates have an important influence on local climate planning.

Serious Gaming for Climate Adaptation—Assessing the Potential and Challenges of a Digital Serious Game for Urban Climate Adaptation

Serious gaming has gained increasing prominence in climate change communication, and provides opportunity to engage new audiences and new platforms for knowledge co-creation and dialogues. This paper presents the design and evaluation of a serious game on climate adaptation, primarily targeted towards high school students, practitioners and politicians. The game aims to provide an experience of the impact of climate adaptation measures, and illustrates links with selected Agenda 2030 goals, which the player has to consider, while limiting impacts of hazardous climate events. The game design builds on the key goals in Education for Sustainable Development combining comprehensive views, action competence, learner engagement and pluralism. This study draws on game sessions and surveys with high school students in Sweden, and aims to assess to what extent different aspects of the game can support an increased understanding of the needs and benefits of adaptation actions. The results of this study indicate that the game can engage players to reflect upon challenges related to climate adaptation decision making, but also point towards the challenge of including a high degree of complexity which can make it difficult to grasp consequences of individual measures, as well as to link these to the natural variability of the occurrence of extreme climatic events.

Right tree, right place (urban canyon): Tree species selection approach for optimum urban heat mitigation - development and evaluation

The re-integration of trees into the urban landscape is a veritable strategy for urban climate mitigation and adaptation. However, dysfunctional trees in terms of urban heat mitigation are dominant in many sub-tropical cities' landscapes due to the lack of scientific basis of tree selection. Therefore, this study proposes and evaluates a methodological framework as an approach for “right tree, right place” for urban heat mitigation through parametric ENVI-met simulations that involve the combination of 54 generic tree forms and 10 characteristic urban morphology – Sky-View Factor (SVF). Results show variable temperature regulation by tree forms (species) with varying magnitude in different urban morphology. Daytime and nighttime temperature regulation effects were between 0.3 °C – 1.0 °C and 0.0 °C – 2.0 °C, respectively depending on tree forms and SVF value. Furthermore, the Heat Reduction Potential (HRP) of trees forms were determined in terms of their human thermal comfort improvement. In general, we found a range of +5% and − 20% depending on SVF, negative and positive values imply heat reduction and increment, respectively. With the competing shading effect of buildings, the HRP of trees reduces from high to low SVF area with variable magnitude among tree forms (species). Hence, the proposed morphology-based tree selection approach was evaluated by comparison with two uninformed selection approaches in a realistic urban neighborhood in Hong Kong. Results clearly indicate the proposed approach's capability in improving human thermal comfort by up two times more than either of the other approaches. Finally, evidence-based recommendations were given for the reference of policy-makers when they make urban green development plan.

Towards climate services for European cities: Lessons learnt from the Copernicus project Urban SIS

The growing share of Europe's population living in cities makes urban climate change impact assessment and adaptation a critical issue. The urban environment is characterized by its sensitivity to small-scale meteorological, hydrological and environmental processes. These are generally not fully described in climate models, largely because of the models' insufficient spatial resolution. The Urban SIS climate service offers historical and future simulated data downscaled to 1 km × 1 km resolution over selected European metropolitan areas. The downscaled data are subsequently used as input to air quality and hydrological impact models, all made available to users as Essential Climate Variables and Sectoral Impact Indicators through a web portal. This paper presents the Urban SIS climate service and demonstrates its functionality in a case study in Stockholm city, Sweden. Good model performance was attained for intra-city temperature gradients and small-scale precipitation extremes. Less positive results were obtained for large-scale precipitation and hydrology, mainly due to an insufficient domain size in the meteorological and climate modelling, in turn related to the substantial computational requirements. An uncertainty classification approach was developed to aid the interpretation and user application of the data. We hope our lessons learnt will support future efforts in this direction.

Effect of Urbanization on Ozone and Resultant Health Effects in the Pearl River Delta Region of China

AbstractThe United Nations has reported that 55% of the global population resides in urban areas, and 68% of the population is expected to be urban dwellers by 2050. Urbanization has critical implications for global land cover. Relevant literature has provided evidence attributing climatic effects to urban expansion; however, few studies have investigated the effect on public health and pollutant sensitivity to emissions. This study aimed to characterize the effect of urbanization‐induced changes in regional climate on ozone (O3), to evaluate ozone sensitivity to nitrogen oxide (NOx) and volatile organic compound (VOC) emissions, and to estimate premature mortalities due to O3 exposure. We employed atmospheric models with the higher‐order decoupled direct method to simulate effects of urbanization on O3 and to determine O3 sensitivity to NOx and VOC emissions. China‐specific concentration response functions were utilized to estimate cardiovascular and respiratory mortalities due to ozone exposure. Urbanization increased O3, which translated to a 39.6% increase in O3‐induced premature mortality (1,100 deaths). Moreover, O3 has become less/more sensitive to unit changes in NOx and VOC emissions in various cities. Urban greening may reduce urban temperature, but it may increase O3 in some cities due to the additional VOC emissions of greening. These findings highlight the strong interactions between land use policies, urban climate adaptation strategies, and air quality policies, suggesting the need of cobeneficial strategies and policies. We proposed a precision environmental management concept that emphasizes the importance of considering the specific atmospheric condition and composition of a city when formulating its environmental policies.

Green Roofs and Greenpass

The United Nations have identified climate change as the greatest threat to human life. As current research shows, urban areas are more vulnerable to climate change than rural areas. Numerous people are affected by climate change in their daily life, health and well-being. The need to react is undisputed and has led to numerous guidelines and directives for urban climate adaptation. Plants are commonly mentioned and recommended as one key to urban climate adaptation. Due to shading of open space and building surfaces, as well as evapotranspiration, plants reduce the energy load on the urban fabric and increase thermal comfort and climate resilience amongst many other ecosystem services. Plants, therefore, are described as green infrastructure (GI), because of the beneficial effects they provide. Extensive green roofs are often discussed regarding their impact on thermal comfort for pedestrians and physical properties of buildings. By means of Stadslab2050 project Elief Playhouse in Antwerp, Belgium, a single-story building in the courtyard of a perimeter block, the effects of different extensive green roof designs (A and B) on the microclimate, human comfort at ground and roof level, as well as building physics are analyzed and compared to the actual roofing (bitumen membrane) as the Status Quo variant. For the analyses and evaluation of the different designs the innovative Green Performance Assessment System (GREENPASS®) method has been chosen. The planning tool combines spatial and volumetric analyses with complex 3D microclimate simulations to calculate key performance indicators such as thermal comfort score, thermal storage score, thermal load score, run-off and carbon sequestration. Complementary maps and graphs are compiled. Overall, the chosen method allows to understand, compare and optimize project designs and performance. The results for the Elief Playhouse show that the implementation of green roofs serves a slight contribution to the urban energy balance but a huge impact on the building and humans. Variant B with entire greening performs better in all considered indicators, than the less greened design Variant A and the actual Status Quo. Variant B will probably bring a greater cost/benefit than Variant A and is thus recommended.

Leveraging public adaptation finance through urban land reclamation: cases from Germany, the Netherlands and the Maldives

Flood risk in urban areas around the world is increasing due to socio-economic development and climate change. Urban climate adaptation measures are beneficial over the longer term, particularly in coastal areas, yet the upfront costs of such measures are significant. Moreover, public actors responsible for adaptation to flood risk face constrained budgets. A promising strategy for overcoming these constraints and enabling greater adaptation investment is land reclamation that includes adaptation, i.e. flood risk reduction. Land reclamation in high-value urban areas can generate substantial revenues through the sale or lease of new land, or taxes on increased economic activities, thus offsetting public adaptation investments. This paper explores the potential of land reclamation for leveraging public adaptation investments and associated distributional issues, by analysing 3 urban land reclamation and adaptation projects in Germany, the Netherlands and the Maldives. We find that all projects have leveraging potential, and leveraging in projects primarily aimed at land creation is particularly high. Further, due to low adaptation costs needed to protect revenue streams in such projects, these investments appear to be ‘low-regret’. Regarding distributional aspects, high project costs and limited public budgets for adaptation constrain public actors’ ability to ensure equitable outcomes through planning instruments, for example, social housing. Further, in implementation, competition for project benefits can lead to further inequalities. We conclude that urban land reclamation presents a significant opportunity to leverage public adaptation investments under certain conditions. We further outline future research needs including to extend land-based financing theory from related urban infrastructure sectors to inform the design of equitable governance arrangements and to better understand the role of such urban land reclamation projects in regional or national development pathways.

Integration of multiple methodologies to evaluate effects of Nature Based Solutions on urban climate mitigation and adaptation

Nature Based Solutions contribute both to mitigate and to adapt the cities to the impacts caused by climate change at urban level. Several methods and tools exist for assessing each strategy. However, none of them allow to cover the whole steps included from analyzing climate trends that could affect the cities, to NBS effectiveness. This paper reviews and classifies existing methods according to the relevant steps of climate resilience and NBS effectiveness, and a combination of various of those methods is presented in a practical case study. Bottom-up city energy, economic and environmental modelling have been performed to understand mitigation effects of NBS implementation at building and neighborhood level. Urban hydrodynamics and fluid dynamics have been modelled too, allowing the estimation of the adaptation effectiveness of the NBS scenarios in flooding and temperatures reduction respectively. Moreover, city vulnerability and urban risks, considering IPCC scenarios regarding climate trends, have been assessed to understand the areas of the city more vulnerable to the impact of climate change. Results show that strategies and climate hazards has been worked in a split way and there is a need to connect better mitigation and adaptation information to facilitate the municipalities taking robust decisions regarding the NBS implementation.

Green infrastructure and urban sustainability: A discussion of recent advances and future challenges based on multiyear observations in New York City

Although the majority of urban green infrastructure (GI) programs in the United States, and elsewhere, are being driven by stormwater management challenges arising as a result of the impervious nature of modern cities, GI is also believed to provide other benefits that enhance urban sustainability. This article uses a case study approach to discuss the role that GI systems might play in urban climate adaptation strategies for cities like New York City, where increases in both temperature and precipitation are projected over the coming decades. Examples of work conducted by the author and colleagues in New York City to quantify the performance of urban GI are first summarized. This work includes monitoring efforts to understand how extensive green roofs retain rainfall, reduce surface temperatures, and sequester carbon. Next, a discussion of the advantages that a distributed, or neighborhood-level, GI system might bring to a climate adaptation strategy is provided. The article then concludes with an outline of some of the future work that is needed to fully realize the potential of urban GI systems to address future climate change impacts.