Over the past 100 years global mean surface temperatures have risen 0.74°C and precipitation patterns have significantly changed.
These recent climatic changes are, at least partly, caused by the impact of human activities on the earth’s natural greenhouse effect. This enhanced greenhouse effect is caused by a strong increase of long lived greenhouse gases (GHG’s) in the atmosphere (H2O, CO2, CH4, and N2O). These GHG’s are produced and emitted to the atmosphere in large amounts due to human activities, like industrial processes, energy production, agriculture, biomass burning and waste management. However, the atmospheric CO2 concentration increases at about half the rate implied by human induced emissions. The remainder of these anthropogenic emissions is currently being taken up by the ocean and terrestrial ecosystems.
Knowledge about climate change is based on a vast amount of research on the climate system. In the past, only the atmosphere itself was researched to explain climate variability. Later, the oceans and seas were included in the research, which greatly improved the validity of the models. However, the land-atmosphere interactions were still missing. About twenty years ago, Wageningen university was one of the first to start contributing the land aspect to climate models. The ESS CALM research cluster Land Atmosphere Interactions, together with other groups studies exchange of water, carbon dioxide, other greenhouse gases (GHG), air pollutants and reactive gases between the land surface and the atmosphere, as affected by vegetation, soils, and weather. Various measurement techniques are used targeting different scales, varying from experimental lab scale, plot scale, flux tower and aircraft measurements. Modelling activities address the same range of scales with detailed soil-vegetation models, atmospheric column models or regional atmospheric models. The research group addresses grassland, cropland and forest ecosystems in the Netherlands in other parts of the world, like Amazonia, Siberia, Malaysia and Sahel. In addition, the urban environment is observed and modeled. The work is linked to large-scale water cycles studies through the spatial integration and feedbacks domains, and joint development of model components.
Aims of the research are both contributing to a better understanding of the climate system through data and modeling (contributing to IPCC reports which led to a shared Nobel Peace prize in 2007); and finding and testing options to reduce GHG emissions. Results are used for UNFCCC, European and national mitigation policy (for example, because of the Kyoto obligations), but also at lower levels of scale research outputs can be put into practice, down to the level of an individual farmer.