Humans Have Driven the Earth’s Freshwater Cycle Out of Its Stable State

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New analysis shows that the global freshwater cycle has shifted far beyond pre-industrial conditions.

New analysis shows that the global freshwater cycle has shifted far beyond pre-industrial conditions.

A new analysis of freshwater resources across the globe shows that human activity has pushed variation in the planet’s freshwater cycle well outside of its pre-industrial range. The study shows that the updated planetary boundary for freshwater change was surpassed by the mid-twentieth century. In other words, for the past century, humans have been pushing the Earth’s freshwater system far beyond the stable conditions that prevailed before industrialization.

This is the first time that global water cycle change has been assessed over such a long timescale with an appropriate reference baseline. The findings, published in Nature Water, show that human pressures, such as dam construction, large-scale irrigation and global warming, have altered freshwater resources to such an extent that their capacity to regulate vital ecological and climatic processes is at risk.

The international research team calculated monthly streamflow and soil moisture at a spatial resolution of roughly 50x50 kilometers using data from hydrological models that combine all major human impacts on the freshwater cycle. As a baseline, they determined the conditions during the pre-industrial period (1661-1860). They then compared the industrial period (1861-2005) against this baseline.

Read more at Aalto University

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