Phenology is the classical study of seasonal plant and animal activity driven by environmental factors, in which interest has recently been revived in the context of climate change. Phenology plays an important role in many biological processes: The onset of phenological phases is driven by environmental factors, especially spring phases are triggered by air temperature. Thus, climate change will cause phenological changes resulting in e.g. modified species (re-)production or competition, length of the growing season, pollen spreading, frost damage, and carbon sequestration. Therefore, phenological changes will affect ecology, agriculture, forestry, and human health as well as the climate system itself through feedback mechanisms. Phenological monitoring has a long tradition in European countries and many long-term (50-100 years) data sets exist. Thus, Europe is a particularly suitable region for investigating phenology providing ‘ground truth’ to earth observation.

POSITIVE will study existing data sets of phenological ground observations in Europe and their relationship with climate and NOAA AVHRR / SPOT4 VEGETATION - NDVI satellite data. Main objective is to develop tools, such as phenological models, as well as techniques for integrating these data for multi-purpose use in the field of global change research: Detection of climate change impacts with phenological and satellite data, modelling phenology under GCM future scenarios, describing the present and future temporal and spatial variability of phenological phases, and providing maps thereof, in order to assess consequences for human health, biodiversity and natural systems.

POSITIVE is divided into three strongly interrelated work-packages:
1. Trends, spatial and temporal variability of phenological phases in Europe,
2. Interpreting the 'Green Wave' in Europe by phenological ground observations, and
3. Phenological models for future scenarios and predictive models of pollen shedding.