Relationships Between Climate variability (water availability) and Ecosystem Productivity: A Satellite Based Study

Abstract:

Climate extremes have resulted in widespread reductions in mean ecosystem productivity, and therefore attracted a lot of studies. Using global satellite and climate products (2000-2011), this study shows that the early 21^st century is water-limited for global biomes, i.e. productivity is proportional to water availability irrespective of dry or wet climate regimes. Cross-biome water-use efficiency is convergent to a single value for all of the driest, wettest and mean climate regimes in this period. No change in WUE along aridity gradient was found at cross-biome levels. Climatic variability generally tends to decrease mean NPP (net primary productivity) but increases NPP variability; however, climatic variability and extremes may affect ecosystem functioning in different and even contrasting ways for different biomes. Impact of dry extremes on reductions in vegetation productivity dominates over effects of wet extremes on productivity increases in the early 21^st century. Future projections of climate forcing and ecosystem response should move beyond evaluation of “mean” behavior, and towards “variability” and “extremes”.