The global climate has changed – and it will continue to change. The Intergovernmental Panel on Climate Change (IPCC) regularly publishes the latest research on past trends and future climate projections worldwide (cf. IPCC 2021). Cities and metropolitan areas are particularly affected by climate change, while also being major emitters of greenhouse gases that drive it (cf. IPCC 2022).
According to calculations by the Potsdam Institute for Climate Impact Research (PIK), the climate in Berlin in 2100 will be similar to that of Toulouse in southern France today (cf. Reusswig et al. 2016). The rise in extreme weather events, such as prolonged heatwaves, droughts, and heavy rainfall, poses immense challenges for society.
The Berlin Climate Modelling of 2022 not only captures the city’s current climate but also offers a glimpse into the future. For this purpose, the development of specific temperature threshold days was modelled. These refer to days when predefined meteorological thresholds are met or exceeded. In the urban climate context, the following threshold days are particularly relevant, as they illustrate the bioclimatic burden in settlement areas. These include:
- 04.12.01 Summer days (max. temperature ≥ 25 °C),
- 04.12.02 Hot days (max. temperature ≥ 30 °C), and
- 04.12.03 Tropical nights (min. temperature ≥ 20 °C).
The number of each threshold day was determined for three periods: the reference period from 1971 to 2000, and the future periods from 2031 to 2060 and 2071 to 2100. The projected climate developments were also taken into account.
These calculations of the temperature threshold days add to the results of the updated Climate Analysis, providing insights into the spatial distribution and evolving frequency of heat events over time.