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Subject: Regime shift ×

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    Understanding of water resilience in the Anthropocene
    (Amsterdam : Elsevier, 2019) Falkenmark, Malin; Wang-Erlandsson, Lan; Rockström, Johan
    Water is indispensable for Earth resilience and sustainable development. The capacity of social-ecological systems to deal with shocks, adapting to changing conditions and transforming in situations of crisis are fundamentally dependent on the functions of water to e.g., regulate the Earth's climate, support biomass production, and supply water resources for human societies. However, massive, inter-connected, human interference involving climate forcing, water withdrawal, dam constructions, and land-use change have significantly disturbed these water functions and induced regime shifts in social-ecological systems. In many cases, changes in core water functions have pushed systems beyond tipping points and led to fundamental shifts in system feedback. Examples of such transgressions, where water has played a critical role, are collapse of aquatic systems beyond water quality and quantity thresholds, desertification due to soil and ecosystem degradation, and tropical forest dieback associated with self-amplifying moisture and carbon feedbacks. Here, we aggregate the volumes and flows of water involved in water functions globally, and review the evidence of freshwater related linear collapse and non-linear tipping points in ecological and social systems through the lens of resilience theory. Based on the literature review, we synthesize the role of water in mediating different types of ecosystem regime shifts, and generalize the process by which life support systems are at risk of collapsing due to loss of water functions. We conclude that water plays a fundamental role in providing social-ecological resilience, and suggest that further research is needed to understand how the erosion of water resilience at local and regional scale may potentially interact, cascade, or amplify through the complex, globally hyper-connected networks of the Anthropocene. © 2018 The Authors
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    Hydrological extremes in the Aksu‑tarim river Basin: Climatology and regime shift
    (Heidelberg : Springer, 2015) Tao, Hui; Borth, Hartmut; Fraedrich, Klaus; Schneidereit, Andrea; Zhu, Xiuhua
    Precipitation data between 1961 and 2010 from 39 meteorological stations in the Tarim River Basin are analyzed to classify and investigate hydrological drought and wetness conditions by using the standardized precipitation index (SPI). The leading time and spatial variability of hydrological drought has been investigated by applying a principal component analysis and Varimax rotation to the SPI on a time scale of 24 months. The results suggest that the western basin is characterized by a clear tendency towards wetter conditions after the middle of the 1980s, which results from an increase in the number of wet extremes and can be considered as a regime shift. Subdividing the period of analysis into two parts (1961–1986 and 1987–2010) this change can be clearly seen in a shift of the probability distribution function of precipitation events. Composite analyses of monthly mean geopotential height fields and wind fields of the ERA-40 data set show that enhanced wetness in the Tarim River Basin after the middle of 1980s is closely related to cyclonic anomalies on the European continent and circulation anomalies over mid-latitude of the Northern Hemisphere. Further correlation analysis between the principal components of SPI and large circulation indices shows that hydrological extremes in the Tarim River Basin correlate with indices related to the polar vortex and subtropical high.