Rethinking urban heat stress: Assessing risk and adaptation options across socioeconomic groups in Bonn, Germany

Urbanization and ongoing climate change increase the exposure of the populations to heat stress, and the urban heat island (UHI) effect may magnify heat-related mortality, especially during heatwaves. We studied temperature-related mortality in the city of Helsinki—with urban and suburban land uses—and in the surrounding Helsinki-Uusimaa hospital district (HUS-H, excluding Helsinki)—with more rural types of land uses—in southern Finland for two decades, 2000–2018. Dependence of the risk of daily all-cause deaths (all-age and 75+ years) on daily mean temperature was modelled using the distributed lag nonlinear model (DLNM). The modelled relationships were applied in assessing deaths attributable to four intensive heatwaves during the study period. The results showed that the heat-related mortality risk was substantially higher in Helsinki than in HUS-H, and the mortality rates attributable to four intensive heatwaves (2003, 2010, 2014 and 2018) were about 2.5 times higher in Helsinki than in HUS-H. Among the elderly, heat-related risks were also higher in Helsinki, while cold-related risks were higher in the surrounding region. The temperature ranges recorded in the fairly coarse resolution gridded datasets were not distinctly different in the two considered regions. It is therefore probable that the modelling underestimated the actual exposure to the heat stress in Helsinki. We also studied the modifying, short-term impact of air quality on the modelled temperature-mortality association in Helsinki; this effect was found to be small. We discuss a need for higher resolution data and modelling the UHI effect, and regional differences in vulnerability to thermal stress.

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Evaluating the Effects of Façade Greening on Human Bioclimate in a Complex Urban Environment

Advances in Meteorology ◽

10.1155/2015/747259 ◽

2015 ◽

Vol 2015 ◽

pp. 1-15 ◽

Cited By ~ 43

Author(s):

Britta Jänicke ◽

Fred Meier ◽

Marie-Therese Hoelscher ◽

Dieter Scherer

Keyword(s):

Heat Stress ◽

Short Wave ◽

Wave Radiation ◽

Short Wave Radiation ◽

Long Wave ◽

Building Facades ◽

Urban Heat ◽

The Mean ◽

Human Bioclimate ◽

Radiant Temperature

The evaluation of the effectiveness of countermeasures for a reduction of urban heat stress, such as façade greening, is challenging due to lacking transferability of results from one location to another. Furthermore, complex variables such as the mean radiant temperature(Tmrt)are necessary to assess outdoor human bioclimate. We observedTmrtin front of a building façade in Berlin, Germany, which is half-greened while the other part is bare.Tmrtwas reduced (mean 2 K) in front of the greened compared to the bare façade. To overcome observational shortcomings, we applied the microscale models ENVI-met, RayMan, and SOLWEIG. We evaluated these models based on observations. Our results show thatTmrt(MD = −1.93 K) and downward short-wave radiation (MD = 14.39 W/m2) were sufficiently simulated in contrast to upward short-wave and long-wave radiation. Finally, we compare the simulated reduction ofTmrtwith the observed one in front of the façade greening, showing that the models were not able to simulate the effects of façade greening with the applied settings. Our results reveal that façade greening contributes only slightly to a reduction of heat stress in front of building façades.

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Urban Heat Stress and Mitigation Solutions

10.1201/9781003045922 ◽

2021 ◽

Author(s):

Vincenzo Costanzo ◽

Gianpiero Evola ◽

Luigi Marletta

Keyword(s):

Heat Stress ◽

Urban Heat

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Patterns of Urban Heat Island Effect in Adelaide: A Mobile Traverse Experiment

Modern Applied Science ◽

10.5539/mas.v11n4p80 ◽

2017 ◽

Vol 11 (4) ◽

pp. 80

Author(s):

Ehsan Sharifi ◽

Ali Soltani

Keyword(s):

Heat Stress ◽

Urban Heat Island ◽

Urban Policy ◽

Urban Heat Island Effect ◽

Urban Structure ◽

Heat Island ◽

Near Surface ◽

Island Effect ◽

Urban Rural ◽

Urban Heat

Urban structure, hard surfaces and shortage of vegetation cause an artificial temperature increase in cities, known as the urban heat island effect. This paper determines the daily patterns of urban heat in Adelaide, Australia. The near-surface temperature profile of Adelaide was mapped in 60 journeys alongside a straight cross route connecting Adelaide Hills to the West Beach between 26 July and 15 August 2013. Results indicate that the most intense urban-rural temperature differences occurred during midnight in Adelaide. However, the afternoon urban heat had more temperature variation in the urban area. In the late afternoon, the near-surface urban heat fluctuates by 2°C within three kilometres and by 1.2°C in just one kilometer. Afternoon heat stress can vary based on space configurations and urban surface covers. Afternoon heat stress causes the highest heat load on urban dwellers. A better understanding of daily urban heat variations in cities assists urban policy making and public life management in the context of climate change.

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The Hydrological Urban Heat Island: Determinants of Acute and Chronic Heat Stress in Urban Streams

JAWRA Journal of the American Water Resources Association ◽

10.1111/1752-1688.12963 ◽

2021 ◽

Author(s):

Einara Zahn ◽

Claire Welty ◽

James A. Smith ◽

Stanley J. Kemp ◽

Mary‐Lynn Baeck ◽

...

Keyword(s):

Heat Stress ◽

Urban Heat Island ◽

Urban Streams ◽

Heat Island ◽

Urban Heat

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Spatiotemporal assessment of heat risk for high-density urban areas: a case study in Dublin, Ireland

10.5194/egusphere-egu21-11663 ◽

2021 ◽

Author(s):

Barry O'Dwyer ◽

Roberta Paranunzio ◽

Edward Dwyer

Keyword(s):

Climate Change ◽

Heat Stress ◽

Urban Areas ◽

Spatial Planning ◽

Radiative Forcing ◽

Climate Index ◽

Spatially Explicit ◽

Urban Heat ◽

Heat Risk ◽

Projected Changes

<p>Ireland&#8217;s climate is changing and these changes are projected to intensify into the future posing an increasing risk to Ireland&#8217;s environment, society and economy. For Ireland and its urban areas in particular, projected changes in the frequency and intensity of heatwaves is considered a moderate but real risk. For example, it is considered likely that Ireland&#8217;s capital city Dublin will experience increases in the frequency and intensity of heatwaves under projected climate change. Moreover Ireland&#8217;s population is ageing faster than other parts of Europe and becoming increasingly vulnerable to heat stress.</p><p>To date, little attention has focussed on heat-related risks for Ireland&#8217;s urban areas, focussing primarily on risks associated with sea level rise and changing patterns of precipitation. Through this work, we provide an innovative approach that allows for the integrated assessment of current and future heat risk for the Greater Dublin Area. &#160;Employing a range of modelling approaches, landcover projections have been developed and future changes in urban heat projected, and spatiotemporal variations in level of exposure to heat stress have been calculated using the Universal Thermal Climate Index (UTCI) for current and future periods (2020s &#8211; 2050s) under a range of radiative forcing scenarios (RCP4.5 and 8.5).&#160; These assessments are combined with vulnerability information (socio-economic data) to obtain spatially-explicit indexes of heat risk and for different scenarios (RCPs). As a result of projected changes in landcover and temperatures, our assessments show that the level of exposure to extreme heat stress will increase in the coming decades and this is particularly the case for the RCP 8.5 scenario. In combination with assessments of vulnerability, this study identifies significant spatial clusters in the denser urban core of the city and peri-urban areas that are considered to be at relatively high levels of heat risk.</p><p>Spatial planning and land use planning are emerging as policy areas that can have significant influence on adaptation to and mitigation of climate change. Through spatial planning, the ways in which cities are designed in order to minimise risks can be re-evaluated and the complexity and uncertainty of climate change tackled. &#160;This study provides spatially explicit information at a fine scale on the evolution of exposure and vulnerability related to thermal heat stress that will support stakeholders to implement strategies and policies aimed at mitigating and adapting to ongoing and future urban heat risk. &#160;</p><div>&#160;</div>

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