N
umerous adaptation strategies are known to humankind, however none of them all-healing and easy-toimplement. Carbon reduction as one of the widely pursued mitigation solutions seems to have no direct impact on the adaptation capacity of cities and other tools are due to the lack of public support often considered to be too complex and cost-demanding for investors and for users of urban spaces. Obviously, only an appropriate attention paid to possible climatic threats and to the estimated effects of wellthought-of adaptation strategies will balance the costs and efforts of complex, comprehensive solutions. What are these however? And, knowing how urgent the necessity of adaptation is, the next question will be: How shall cities of the future look like? Before seeking answers to these questions, a short outline of a few important factors that influence urban climate might be useful: In cities, the urban form and geometry affect the incoming solar radiation and ventilation conditions, causing heat trapping in man-made surfaces (Givoni 1998, Emmanuel 2005). In addition to that, the natural water cycle modifies in cities significantly as a result of sealing of surfaces and withdrawing vegetation: if rainwater is led into sewage, it cannot evaporate through plants as effectively as it would in natural environments (Schmidt 2010). This means that in cities, the desired cooling effect of vegetation is being restrained. These phenomena result in microclimatic conditions that might be unfavourable for cities' inhabitants, accompanied by the well-known phenomenon of the urban heat island (UHI). More than that, the effect of the UHI exaggerates when extreme weather events occur, such as heat waves. In such situations, inhabitants, mostly elderly people or people with cardio-vascular problems, might suffer from severe health problems. This threat will become even more alarming with the expected climate change. On the other hand, the above-mentioned factors, urban form and surface design, also play a significant role in adaptation strategies; an option would be to reproduce natural conditions in urban environments (We all would favour
"green cities" over those with lack of green spaces, wouldn't we?). It is indeed the way the urban geometry and the urban surfaces are designed that may alleviate the UHI effect (and improve the microclimatic conditions in general) through purposeful influencing of the natural energy flows: via intended street orientation and built masses' proportions, shading and ventilation and via enhancing the ratio of evaporative surfaces and vegetated areas in cities. As such, maximal cooling effects during hot summers can be provided. This means that pursuing particular urban design strategies can help tackle microclimatic and UHI-related problems, if these address equally and comprehensively the issues of urban form and building and landscape design. Such climate-responsive strategies, composed in a set of urban design guidelines, could easily become official urban climate change adaptation programs. For hot climates, urban design recommendations have been suggested by Givoni (1998) and Emmanuel (2005); Stone's recommendations (2012) relate to moderate climate. Regrettably, cities seem to underestimate the urgency of adaptation strategies – no known legally binding climate-related urban design guidelines have been adapted yet. Berlin's "City Development Plan Climate" is among first guiding documents of its kind to be followed in new developments or when retrofitting old ones. Other cities partially consider climatic aspects and adaptation strategies when addressing the themes of surface design and rainwater management, for instance, NYC' High Performance Infrastructure Guidelines, Chicago's Guide to Stormwater Best Management Practices and others. Yet it seems to be a long way until all aspects – urban form and geometry and landscape and building design – and, first of all, their effects on the extent of heat islands – will gain necessary attention in the urban development process and in cities' policies. In the thesis "Climate-Sensitive Urban Design in the Moderate Climate Zone – Responding to Future Heatwaves. Case study Berlin Heidestrasse/Europacity" (2010), the author developed urban a set of design recommendations for the UHI mitigation and climate change adaptation in
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