Modeling the effects of global change on ecosystem properties - past and future.
The expected effects of climate change on ecosystem properties span a wide range from carbon storage, water resources, timber and crop yield but also the distribution of species. Within the group of researchers that I am leading we are approaching the problem with a variety of approaches of which many are highly computational intensive. In one project we project the occurrence of 600 species in combinations of climate projections, representative concentration pathways, data resolutions and species distribution models to assess the ability of current modeling approaches to correctly predict species occurrence. While the projection of a single species within a single combination of the mentioned drivers is not computationally demanding, the high number of combinations which need to be calculated results in a high computational demand. However, they also allow for an easy parallelization. Another aspect that is currently worked at in my working group is the reconstruction of tree migration over the Holocene. Here we use a combination of a dispersal model and a dynamic vegetation model. This combination is highly computational demanding since typically the number of cells to be simulated is given by the resolution of the climate, but in this case we have to simulate on a higher resolution and the different cells have to interact with each other to exchange seeds and allow trees to migrate through the European continent. In a third project we are also working with a vegetation model at a very high resolution as we improve the results of the vegetation model with remotely sensed data which is available globally at a resolution of 1km. Again these analyses require parallelization.