Clearly visible changes in the timing of phenological phases, such as leaf unfolding or flowering, confirm that phenology is probably the most simplest process in which to track Global Change. Due to long phenological tradition in many countries, Europe is a particularly suitable region for investigating and modelling phenological changes which could be relevant for a large number of disciplines ranging from biodiversity, agriculture, and forestry to human health and via feed-back mechanism to the climate system itself. Within POSITIVE (Phenological Observations and Satellite data (NDVI): Trends in the Vegetation Cycle in Europe), funded by the 5th Framework Programme of the European Union, a database of phenological observations from 10 European countries, meteorological data as well as different NDVI products allowed the development of tools and techniques for integrating climate, satellite data and phenological ‘ground truth’ in the field of Global Change research: The spatial and temporal variability of onsets and trends was analysed and their long-term changes were related to meteorology and atmospheric circulation patterns, such as NAO. Phenological spring and autumn models were developed to assess shifts under GCM scenarios. The coherence of changes derived from satellite images and detected by phenological observations was tested for different sites in Europe. Large scale growing season duration for the northern hemisphere and changes in the photosynthetic capacity were supported by local studies of GPP, satellite data and phenology. In addition, a new pollen shedding model for the main allergenic taxa allows the forecast weekly pollen concentrations at particular sites and will be soon available for the public at the POSITVE project website http://www.forst.tu-muenchen.de/EXT/LST/METEO/positive.