Projection of the rural and urban human thermal comfort in the Netherlands for 2050

Hot summer days may lead to reduced thermal discomfort, labour productivity, and higher morbidity and mortality for vulnerable groups. The projected climate change may raise this thermal discomfort in the future. To implement measures to prevent adverse health conditions, robust estimates of the future human thermal comfort (HTC) are required. This study analyses the future HTC for both coastal and inland Dutch cities and countryside. The future conditions are based on the KNMI-06 climate scenarios. Using these scenarios, observed weather data from 1976 to 2005 are transformed to future weather design data representative for 2050. Subsequently, HTC expressed in the physiological equivalent temperature (PET) is estimated for these future scenarios. A substantial increase of heat stress abundance is foreseen in all climate scenarios, for both urban and rural areas, particularly, under the most intense warming. In these scenarios, the frequency of hours with heat stress will more than double, and the increase will develop faster in an urban canyon than in rural areas. In urban areas, PET shows a maximum as function of sky-view factor (SVF), i.e. for a smaller SVF a wind speed reduction increases the PET on one hand and shading reduces the PET on the other hand.