摘要：The functioning of many ecosystems and their associated resilience could become
severely compromised by climate change over the 21st century. We present a global
risk analysis of terrestrial ecosystem changes based on an aggregate metric of
joint changes in macroscopic ecosystem features including vegetation structure
as well as carbon and water fluxes and stores. We apply this metric to global
ecosystem simulations with a dynamic global vegetation model (LPJmL) under
58 WCRP CMIP3 climate change projections. Given the current knowledge of
ecosystem processes and projected climate change patterns, we find that severe
ecosystem changes cannot be excluded on any continent. They are likely to occur (in > 90% of the climate projections) in the boreal–temperate ecotone where heat and drought stress might
lead to large-scale forest die-back, along boreal and mountainous tree lines where the temperature
limitation will be alleviated, and in water-limited ecosystems where elevated atmospheric
CO2 concentration will lead to increased water use efficiency of photosynthesis. Considerable
ecosystem changes can be expected above 3 K local temperature change in cold and tropical
climates and above 4 K in the temperate zone. Sensitivity to temperature change increases
with decreasing precipitation in tropical and temperate ecosystems. In summary, there is a
risk of substantial restructuring of the global land biosphere on current trajectories of
climate change.
