Biodiversity Scenarios: Projections of 21st century change in biodiversity and associated ecosystem services

Abstract

This synthesis focuses on estimates of biodiversity change as projected for the 21st century by models or extrapolations based on experiments and observed trends. The term ‘biodiversity’ is used in a broad sense as it is defined in the Convention on Biological Diversity to mean the abundance and distributions of and interactions between genotypes, species, communities, ecosystems and biomes. This synthesis pays particular attention to the interactions between biodiversity and ecosystem services and to critical ‘tipping points’ that could lead to large, rapid and potentially irreversible changes. Comparisons between models are used to estimate the range of projections and to identify sources of uncertainty. Experiments and observed trends are used to check the plausibility of these projections. In addition possible actions have been identified at the local, national and international levels that can be taken to conserve biodiversity. A wide range of scientists participated in this synthesis, with the objective to provide decision makers with messages that reflect the consensus of the scientific community and that will aid in the development of policy and management strategies that are ambitious, forward looking and proactive.