The temperature is rising due to climate change, resulting in more heat waves and more hot days and nights. All government agencies (municipalities, provincial governments and water boards) in the Netherlands must therefore identify the bottlenecks relating to flooding, heat, drought and floods before 2020. RIVM has proposed standardising the ‘test for heat stress’. To this end, a guideline has been drawn up for municipalities to enable them to list 24 possible risks, divided into 5 themes: health, networks, water, quality of life and outdoor space.
A new method has been developed for calculating heat maps, with the wind chill temperature as starting point, that can be used to assess heat stress. Using this new method, the standard heat map, with wind chill temperature, can be calculated on a hot day.
There are currently a lot of heat maps available, all showing the heat in different ways. Urban areas are often warmer than rural ones, partly because of the use of dark materials, such as asphalt, and lower wind speeds (heat island). The standard calculation takes into account various weather parameters, the local spatial situation, the land use and the location of buildings and trees. In this study, standardised maps have been developed for the city of Wageningen. For the stress test to become more applicable, it is important that new heat maps are developed on a national scale and made available in the Climate Effect Atlas. A map with the number of hot nights has already been included in this digital atlas.
Prolonged periods of heat can cause nuisance, varying from a lack of sleep to a life-threatening disturbance of bodily functions, as is the case with sunstroke. More people die than ‘normal’ when it is very hot; the elderly and people with chronic disorders, such as pulmonary and cardiac complaints, are particularly vulnerable. RIVM recommends the identification of these health risks for the Netherlands. The most important parameters are the number of additional hospitalisations resulting from the heat and the number of deaths in excess of the ‘normal’ numbers.
Source: de Nijs, T., Bosch, P., Brand, E., Heusinkveld, B., van der Hoeven, F., Jacobs, C. M. J., Klok, L., Kluck, J., Koekoek, A., Koopmans, S., van Nieuwaal, K., Ronda, R., & Steeneveld, G. (2019). Ontwikkeling standaard stresstest hitte. (RIVM briefrapport; No. 2019-0008). Rijksinstituut voor Volksgezondheid en Milieu. https://edepot.wur.nl/477495