SMHI has estimated that extreme heat events, which so far have occurred every twenty years on average, may occur every three to five years by the end of the century.
High temperatures over a sustained period of time can have negative effects on health. Young children, the elderly and the sick are particularly vulnerable. According to studies carried out at Umeå University, the 2018 heatwave caused 700 premature deaths.
The summer of 2018 highlighted a number of problems that can arise in connection with high temperatures and long periods of heat. Although we cannot say that future summers will be exactly the same as 2018, we know that they will become warmer and that the problems we experienced then will become more common in future. In terms of climate change adaptation, summer 2018 can serve as a test and measures can be introduced with the aim of avoiding the problems that arose in 2018.
Different types of preparedness
The requirements for preparedness within social authorities, municipal operations and care services are increasing in order to reduce the health effects of a heatwave. Preparedness includes advice and action plans for acting during a heatwave. The heatwave warning service introduced by SMHI in 2014 is also part of this preparedness work.
In the longer term, our ability to deal with heatwaves will depend on how we build our cities. Physical planning requires understanding and information about how temperature conditions are experienced in different parts of the built environment, and about how they are affected by buildings, materials, vegetation and water.
SMHI and SEI have studied the opportunities for influencing the air temperature in Stockholm through physical planning.
Researchers investigated how the urban climate is affected by the growth and densification of Stockholm, taking summer 2014 as the reference year. A weather forecasting model was used to calculate the summer temperatures we would have had if the city had corresponded to detailed planning and growth scenarios for 2030 and 2050. The main conclusions from the project are:
- Climate-conscious planning makes it possible to achieve a good urban climate, even in the growing Swedish cities of the future.
- Measures within the urban environment to reduce vulnerability in the event of heatwaves should primarily focus on direct effects within the local area, such as proximity to green spaces and shade.
- Extremely high temperatures only occur on a few days a year. When planning, good comfort throughout the year should be striven for. A good basis for climate planning takes account of temperature (air temperature and mean radiant temperature), wind and precipitation at different times of the year.
The study has been carried out within the HazardSupport research project on behalf of the Swedish Civil Contingencies Agency (MSB).