Case Study 2: Phenological Trends in the Federal State of Hesse

In Hesse, a rise in air temperature of about 0.9 °C in average established comparing the climate reference period 1961–1990 and the period 1991–2009. This equals the trend in entire Germany, whilst in some regions even a temperature increase of up to 3 °C was measured. Until the end of the twenty-first century, air temperatures in Hesse are expected to rise between 3.2 and 3.7 °C compared to the reference period 1971–2000. This should also affect the onset and duration of phenological stages of plants implicating serious impacts for environment and economy. In order to deal with this issue, the research project “HeKlimPh” funded by the Hessian Competence Centre of Climate Change modelled spatiotemporal trends of plant phenology as being an indicator for climate change related biological effects. Accordingly, case study 2 describes the coupled analysis of meteorological air temperature data and phenological data indicating different phenological seasons. The data comprise observations on 35 plant phenological phases of wild growing plants, fruits, crops and vines collected at about 6500 observation sites in Germany (553 in Hesse) between 1961–2005. Within a GIS environment, also estimations on the future phenological development for the periods 2031–2060 and 2071–2100 were performed. The projections were based on air temperature grids derived from four regional climate models considering the IPCC emission scenario A1B.