Drawing on the citywide Climate Analysis of 2022 and regional climate model projections from Germany’s National Meteorological Service (DWD), it was examined how selected temperature threshold days are evolving in the State of Berlin. Both sources were used to determine threshold days. The calculations are based on the RCP8.5 scenario of the IPCC (2013). The scenario involves the fundamental assumption that current global socio-economic and climate policy conditions will remain unchanged and that significant climate change will occur by the end of the century.
Results from regional climate projections were also incorporated in order to determine threshold days. The regional model data stems from projections developed under the EURO-CORDEX initiative (cf. Jacob et al. 2014) and the ReKliEs project (cf. Huebener et al. 2017). The DWD refines these datasets by applying bias correction and scaling them to a horizontal resolution of 5 km x 5 km (DWD 2024). These improved datasets are then used for analysing the development of threshold days in the State of Berlin (Fig. 1). The threshold day calculations were based on data from the DWD core ensemble (2018) and on the RCP8.5 scenario, which predicts considerable climate change by the end of the century.
The regional model data includes long-term projections, which allowed for the extraction of maximum and minimum daily temperatures.
In addition to a grid-based evaluation with a resolution of 10 m x 10 m, the average number of temperature threshold days is also determined for the block segment areas of the Urban and Environmental Information System (ISU5) as of 31 December 2020 (SenStadt 2020).