With increase in awareness of the risks posed by climate change and increasingly severe weather events, attention has turned to the need for urgent action. While strategies to respond to flooding and drought are well-established, the effects - and effective response - to heat waves is much less understood. As heat waves become more frequent, longer-lasting and more intense, the Cool Towns project provides cities and municipalities with the knowledge and tools to become heat resilient. The first step to developing effective heat adaptation strategies is identifying which areas in the city experience the most heat stress and who are the residents most affected. This enables decision-makers to prioritise heat adaptation measures and develop a city-wide strategy.The Urban Heat Atlas is the result of four years of research. It contains a collection of heat related maps covering more than 40,000 hectares of urban areas in ten municipalities in England, Belgium, The Netherlands, and France. The maps demonstrate how to conduct a Thermal Comfort Assessment (TCA) systematically to identify heat vulnerabilities and cooling capacity in cities to enable decision-makers to set priorities for action. The comparative analyses of the collated maps also provide a first overview of the current heat resilience state of cities in North-Western Europe.
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Built environments are increasingly vulnerable to the impacts of climate change. Most European towns and cities have developed horizontally over time but are currently in the process of further densification. High-rise developments are being built within city boundaries at an unprecedented rate to accommodate a growing urban population. This densification contributes to the Urban Heat Island phenomenon and can increase the frequency and duration of extreme heat events locally. These new build-up areas, in common with historic city centres, consist mainly of solid surfaces often lacking open green urban spaces.The Intervention Catalogue is the third publication in a series produced by the Cool Towns project and has been designed as a resource for decision makers, urban planners, landscape architects, environmental consultants, elected members and anyone else considering how to mitigate heat stress and increase thermal comfort in urban areas. Technical information on the effectiveness of the full array of intervention types from trees to water features, shading sails to green walls, has been assessed for their heat stress mitigation properties, expressed in Physiological Equivalent Temperature (PET). The results shown in factsheets will help the process of making an informed, evidence based, choice so that the most appropriate intervention for the specific spatial situation can be identified.
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Cities are confronted with more frequent heatwaves of increasing intensity discouraging people from using urban open spaces that are part of their daily lives. Climate proofing cities is an incremental process that should begin where it is needed using the most cost-efficient solutions to mitigate heat stress. However, for this to be achieved the factors that influence the thermal comfort of users, such as the layout of local spaces, their function and the way people use them needs to be identified first. There is currently little evidence available on the effectiveness of heat stress interventions in different types of urban space.The Cool Towns Heat Stress Measurement Protocol provides basic guidance to enable a full Thermal Comfort Assessment (TCA) to be conducted at street-level. Those involved in implementing climate adaptation strategies in urban areas, such as in redevelopments will find practical support to identify places where heat stress may be an issue and suggestions for effective mitigation measures. For others, such as project developers, and spatial designers such as landscape architects and urban planners it provides practical instructions on how to evaluate and provide evidence-based justification for the selection of different cooling interventions for example trees, water features, and shade sails, for climate proofing urban areas.
MULTIFILE
In this study we tested 39 Lactococcus lactis strains isolated from diverse habitats for their robustness under heat and oxidative stress, demonstrating high diversity in survival (up to 4 log units). Strains with an L. lactis subsp. lactis phenotype generally displayed more-robust phenotypes than strains with an L. lactis subsp. cremoris phenotype, whereas the habitat from which the strains had been isolated did not appear to influence stress survival. Comparison of the stress survival phenotypes with already available comparative genomic data sets revealed that the absence or presence of specific genes, including genes encoding a GntR family transcriptional regulator, a manganese ABC transporter permease, a cellobiose phosphotransferase system (PTS) component, the FtsY protein, and hypothetical proteins, was associated with heat or oxidative stress survival. Finally, 14 selected strains also displayed diversity in survival after spray drying, ranging from 20% survival for the most robust strains, which appears acceptable for industrial application, to 0.1% survival for the least-tolerant strains. The high and low levels of survival upon spray drying correlated clearly with the combined robustness under heat and oxidative stress. These results demonstrate the relevance of screening culture collections for robustness under heat and oxidative stress on top of the typical screening for acidifying and flavor-forming properties. © 2014, American Society for Microbiology.
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The liveability of cities worldwide is under threat by the predicted increase in intensity and frequency of heatwaves and the absence of a clear spatial overview of where action to address this. Heat stress impairs vital urban functions (Böcker and Thorsson 2014), hits the local economy (Evers et al. 2020), and brings risks for citizens’ health (Ebi et al. 2021). The ongoing densification of cities may escalate the negative consequences of heat, while rising climate adaptation ambitions require new pathways to (re)design public places for a warmer climate. Currently, policy makers and urban planners rely on remote sensing and modelling to identify potential heat stress locations, but thermal comfort models alone fail to consider socio-environmental vulnerabilities and are often not applicable in different countries (Elnabawi and Hamza 2020).In the Cool Towns Interreg project, researchers collaborated with municipalities and regions to model urban heat stress in nine North-Western European cities, to find vulnerabilities and to measure on the ground (see Spanjar et al. 2020 for methodology) the thermal comfort of residents and the effectiveness of implemented nature-based solutions. Using the Physiological Equivalent Temperature (PET) index, several meteorological scenarios were developed to show the urban areas under threat. The PET maps are complemented by heat vulnerability maps showing key social and environmental indicators. Coupled with local urban planning agendas, the maps allowed partner cities to prioritize neighbourhoods for further investigation. To this end, community amenities and slow traffic routes were mapped on top of the PET maps to identify potential focus areas.A comparative analysis of the collated maps indicates certain spatial typologies, where vital urban activities are often influenced by heat stress, such as shopping areas, mobility hubs, principal bicycle and pedestrian routes. This project has resulted in the development of a multi-level Thermal Comfort Assessment (TCA), highlighting locations where vulnerable user groups are exposed to high temperatures. Standardized for European cities, it is a powerful tool for policy makers and urban planners to strategically identify heat stress risks and prioritize locations for adapting to a changing climate using the appropriate nature-based solutions.
MULTIFILE
While the optimal mean annual temperature for people and nations is said to be between 13 °C and 18 °C, many people live productive lives in regions or countries that commonly exceed this temperature range. One such country is Australia. We carried out an Australia-wide online survey using a structured questionnaire to investigate what temperature people in Australia prefer, both in terms of the local climate and within their homes. More than half of the 1665 respondents (58%) lived in their preferred climatic zone with 60% of respondents preferring a warm climate. Those living in Australia's cool climate zones least preferred that climate. A large majority (83%) were able to reach a comfortable temperature at home with 85% using air-conditioning for cooling. The preferred temperature setting for the air-conditioning devices was 21.7 °C (SD: 2.6 °C). Higher temperature set-points were associated with age, heat tolerance and location. The frequency of air-conditioning use did not depend on the location but rather on a range of other socio-economic factors including having children in the household, the building type, heat stress and heat tolerance. We discuss the role of heat acclimatisation and impacts of increasing air-conditioning use on energy consumption.
MULTIFILE
Urban planning will benefit from tools that can assess the vulnerabilityto thermal stress in urban dense cities. Detailed quick-scan heat stressmaps, as made in this study for Johannesburg, have proven valuable inthe decision-making process on this topic. It raised awareness on theurgent need to implement measures to tackle the effects of climatechange and urbanization. Awareness on heat stress has led to theimplementation of measures to mitigate the effects of climate change.As in other countries, nature-based solutions (e.g. green roofs and walls,swales, rain gardens, planting trees etc) are considered in urban areasin South Africa for various reasons. The awareness of the effect ofnature based solutions on heat stress is still low, which can be improvedby the use of heat stress maps. Some of these measures are alreadymapped on the open source web tool, Climate-scan(www.climatescan.nl) for international knowledge exchange aroundthe globe.
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According to a governmental decision, all (re)constructions in Dutch cities starting by 2020 have to be climate resilient. Part of this climate resilience is also adaptation to (extreme) heat. Although urban heat, its causes, consequences, and potential adaptation measures, have been extensively studied by scientists all over the world, the understanding of this problem among practitioners is still limited. Local governments are struggling with defining the urgency and finding the right arguments for adaptation to this aspect of climate change. Also questions asked by municipality officers often differ from those asked (and answered) by scientists. How do you define “heat stress”? What are the best adaptation measures for our city? How do we know we have reached “heat resilience”? Or; Shall we just do what they do in Italy?Project Heat Resilient Cities is a cooperation of two research institutes, 13 municipalities, and a water authority in Netherlands. The aim of this project is to bring the current knowledge of urban heat adaptation to practice and to fill in the research gabs. The research focuses on clear visualizations of problematic areas, applicable heat resilient measures in Dutch context, and design guidelines leading towards more heat resilient cities. In this presentation, we will present an overview of practical tools (maps, instruments measures, visualizations, guidelines) that cities could use put heat resilience into practice.
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The future will be warmer with more tropical days, heat stress and related impacts for the healthy and liveable city. This is clear from many scientific studies and papers. Yet many local governments in the Netherlands claim to have insufficient understanding of the importance of these impacts in order to make the necessary step to climate adaptation and to take practical actions to manage the risks associated with rising heat levels. They struggle with defining the urgency of heat stress and finding good arguments for the need to adapt urban environments to rising temperatures. In order to provide urban professionals with reasons to adapt their urban environments to heat, we analyzed the potential impacts of urban heat from international policy reports and scientific literature. We summarized the impacts in a mind map. This map visualizes the large number and variety of heat-related risks. They can be subdivided into risks for health, open space, liveability, water and infrastructure networks. We believe that this mind map provides useful insight into the reasons to take heat adaptation actions. It can also be a helpful visual for urban professionals in outlining the reasons to take action for heat adaptation.
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