Deriving future climate reference data for the Swiss building sector

Buildings constructed today will be exposed to climatic changes during their lifetime. Changes in the outdoor climate also affect the indoor climate in buildings where people spend a substantial part of their day. In addition, the building sector significantly contributes to energy demand and greenhouse gas emissions. Therefore, it is vital to design buildings in a way that ensures comfortable indoor temperatures today and in the future while minimizing energy use. For Switzerland, an additional warming of 2-3 degrees Celsius by mid-Century is projected without climate change mitigation. According to the Swiss Climate Scenarios CH2018, heatwaves are set to increase significantly in frequency, intensity and duration, whereas coldwaves will be less common. To adapt to these changes and design buildings optimally for a warmer future climate, climate projections tailored to the needs of the building sector are required.

To serve this demand and together with partners from universities and the industry, MeteoSwiss has created a reference dataset for the future climate for use in building simulations. For this, observations were combined with climate change information from the CH2018 scenarios. The resulting reference data represent the possible future climate at locations across Switzerland. Hourly and physically consistent data for the future for the variables temperature, humidity, wind and solar radiation have been calculated. These represent typical years and warm summer years. The data are available for the near future and the middle of the century and are based on two different greenhouse gas emission scenarios: 'no climate change mitigation' (RCP8.5) and 'concerted climate change mitigation efforts' (RCP2.6). The data are also available for four extra-urban and urban station pairs, which allows evaluating the urban heat island effect.

The described reference data were compiled in close collaboration with users and allows them to design buildings tailored to a warmer climate. Findings from using this data in building simulations allow inferring requirements for the architecture and operation of the buildings and show an increasing demand for cooling systems in the future.