Agriculture and climate - current topics and contributions of agriculturalresearch

Experimental research and modelling of atmospheric-biospheric exchange proc esses of matter as well as related consequences for the energy balance of t he atmosphere and for terrestrial ecosystems are current topics of climate impact research. Agriculture is an important source and sink for a variety of trace or "greenhouse" gases. The present contribution summarizes current results and open questions with regard to causes and consequences of chang es in physical and chemical climate elements related to agriculture. This i ncludes comments on the uncertainties of those data which form the basis fo r the prediction of changes of the physical climate, on the role of aerosol s and on the contribution of agriculture to a potential "negative" climate effect. It is concluded that in order to develop cause-effect relationships e.g. as a basis for abatement strategies additional experimental investiga tions of processes of the exchange of trace gases between the atmosphere an d the biosphere and the development of adequate models to describe these pr ocesses are needed. Particularly, agricultural emission inventories for tra ce constituents with an adequate resolution in space and time and models de scribing the sink properties of whole landscapes are required. Agricultural climate research at the ecosystem level is likely to contribute to answeri ng these questions.