Impact on outdoor spaces

Outdoor spaces are defined as the areas outside our houses and buildings: public and private spaces. These include the areas in which we engage in leisure activities, seek to cool off, and enjoy Nature, such as forests, beaches, parks, and (our own) gardens. They also comprise paved spaces, such as bicycle routes, roads, shopping streets, pavement cafés, plazas, and industrial estates. Heat issues primarily occur in paved areas. The paragraphs below explain the problems that heat can cause in outdoor spaces, and the page on measures to combat heat provides information to address these problems.

Heat issues in outdoor spaces

According to the Heat-proof Cities study conducted by Amsterdam UAS, outdoor heat issues depend on two different types of temperature: ambient temperature and perceived or apparent temperature.

  • High ambient temperatures in an entire city during prolonged heat result in, e.g., warm nights, which prevent many people from getting a good night’s sleep. Due to the heat island effect, cities retain their high ambient temperature for a longer period of time than outlying areas.
  • A high perceived temperature can cause heat stress. The perceived temperature can differ sharply locally and from one person to the next. In a car park directly exposed to the sun, for example, the temperature can be perceived as 10 to 15 degrees higher than in the shade of a tree. The perceived temperature depends on several factors, such as ambient temperature, humidity, ventilation, and heat radiation. Many maps use the PET [physiological equivalent temperature] value to express the perceived temperature. PET is defined as the average perceived temperature on a hot summer day, between noon and 6 PM.

The Guidelines for Standardised Stress Tests help to identify heat issues

What heat-related problems occur in your area? This is one of the questions you need to answer when carrying out a climate stress test for your area. Many types of heat maps can visualise the heat issues affecting an area. Visualising the heat issues in an area is included in the mandatory climate stress test to be conducted by municipal and other government authorities. The Guidelines for Standardised Stress Tests developed under the Delta Plan for Spatial Adaptation can help to determine which heat maps are most appropriate for your situation. These Guidelines refer to several heat maps and their map narratives in the Climate Impact Atlas. These will help you to gain insight into the heat issues in an area.

Neighbourhood Dashboard helps to gain insight into heat issues by neighbourhood

Another useful tool is the Neighbourhood Dashboard [in Dutch] in the Climate Impact Atlas. It contains several indicators that help to understand the heat-related challenges in a neighbourhood. These indicators include perceived temperature, shade, and social vulnerability. For each indicator, you can also find more detailed information in the map narratives:

  • Perceived Temperature: this map shows the perceived temperature during a hot summer afternoon for every place in the Netherlands. For the purpose of the calculations, 1 July 2015 was selected as a representative tropical day.
  • Shade: these maps show how much shade is available in a neighbourhood. There are also maps that show the average percentage of shade for walking and cycling paths.
  • Tree-crown cover: this map shows which areas are covered by tree-crowns, the upper layer of a tree. This provides shade and cooling. You can also use this map to track how this changes over time.
  • Social vulnerability to heat: the maps in this map narrative show by neighbourhood where vulnerable groups live, such as over-65s in poor health and households living at or below the social minimum. These groups are particularly vulnerable to heat.

Other useful maps from the Climate Impact Atlas

The Climate Impact Atlas also features other maps that provide insight into heat issues in your area:

  • The Distance to Cooling map: this map shows which municipal buildings are located at a maximum of 300 metres from a cool spot.
  • Would you like to learn more about the causes and impacts of night heat? Then read the map narrative on night heat.The map shows how often warm evening and nights occur in different regions of the Netherlands. They also provide insight into where people are more likely to experience sleep problems and heat stress.