The UN Convention on Biological Diversity defines biodiversity as "the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems" (UN 1992, p. 3). Biodiversity is often measured as the number of species in a given area and can be explored in terms of genetic, species and ecosystem diversity. The IPCC recognizes the role of biodiversity for serving specific human needs, not to mention their critical importance for the Earth's system functionality and thus for the three pillars of CSA: productivity, adaptation and mitigation. Human activity and climate change both put pressure on biodiversity.