An Evidence-Based Review of Impacts, Strategies and Tools to Mitigate Urban Heat Islands

Abstract

The impacts of climate changes on cities, which are home to over half of the world’s population, are already being felt. In many cases, the intensive speed with which urban centres have been growing means that little attention has been paid to the role played by climatic factors in maintaining quality of life. Among the negative consequences of rapid city growth is the expansion of the problems posed by urban heat islands (UHIs), defined as areas in a city that are much warmer than other sites, especially in comparison with rural areas. This paper analyses the consistency of the UHI-related literature in three stages: first it outlines its characteristics and impacts in a wide variety of cities around the world, which poses pressures to public health in many different countries. Then it introduces strategies which may be employed in order to reduce its effects, and finally it analyses available tools to systematize the initial high level assessment of the phenomenon for multidisciplinary teams involved in the urban planning process. The analysis of literature on the characteristics, impacts, strategies and digital tools to assess on the UHI, reveals the wide variety of parameters, methods, tools and strategies analysed and suggested in the different studies, which does not always allow to compare or standardize the diagnosis or solutions.

The Vertical City Weather Generator (VCWG v1.0.0)

“…VCWG predicted a maximum UHI of +1.8 K in Vancouver, in agreement with measured value of +1.4 K (Runnalls, 1995;Lesnikowski, 2014;Ho et al, 2016). Case studies in Japan have reportedly obtained urban warming in large and developed cities such as Osaka, which is the interest in this study, and Tokyo in the afternoon (Leal Filho et al, 2017). This effect is also predicted by VCWG that showed the average UHI of +1.0 K, which is consistent with other studies measuring an average UHI of +1.5 K (Kusaka et al, 2012;Leal Filho et al, 2017).…”

“…Case studies in Japan have reportedly obtained urban warming in large and developed cities such as Osaka, which is the interest in this study, and Tokyo in the afternoon (Leal Filho et al, 2017). This effect is also predicted by VCWG that showed the average UHI of +1.0 K, which is consistent with other studies measuring an average UHI of +1.5 K (Kusaka et al, 2012;Leal Filho et al, 2017). UHI in Copenhagen is reported to change between +0.5 and +1.5 K depending on the wind speed, which agrees well with the VCWG prediction of +1.3 K, as well as intensifying in the afternoon (Mahura et al, 2009).…”

Statistical Review of Quality Parameters of Blue-Green Infrastructure Elements Important in Mitigating the Effect of the Urban Heat Island in the Temperate Climate (C) Zone

“…Specific solutions that fit into these activities can be divided into the material, structural, and planning strategies. These are: (1) the use of building and finishing materials with a high solar reflection coefficient, (2) the use of evaporation systems on roofs and roads, (3) the introduction of water facilities, green areas and green technical solutions, (4) reduction of anthropogenic heat emission and energy consumption, (5) urban planning taking the local climate into account, and (6) modifying the topography of a city [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”

An Assessment of the Relationships between Extreme Weather Events, Vulnerability, and the Impacts on Human Wellbeing in Latin America

“…Climate events worsen health disparities in developing countries as a whole and weather extremes in particular. As a result, environmental health problems that are associated with the indirect climate impacts [ 16 ], such as stress due, for instance, to damages to crops and properties, thermal discomfort [ 49 ], or increases in the transmission of mosquito-borne diseases [ 50 ] tend to widen the gap and make populations in developing countries even more vulnerable than they already are. Equality stands at the centre of development; the gaps in the provision of services are associated with the persistence of slums, whose inhabitants frequently face higher risks of exposure to communicable diseases, environmental pollution, and natural disasters [ 51 ].…”