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By Isobel Williams via SWNS

Earths freshwater cycle has been knocked out of its stable state by man, warns a new study.

The research shows 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 study, published in the journal Nature Water, explains that for the past century, humans have been pushing the Earths freshwater system far beyond the stable conditions that prevailed before industrialization.

The international research team, led by Aalto University in Finland, notes that this is the first time that global water cycle change has been assessed over such a long timescale with an appropriate reference baseline.

To get their results the researchers 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) and compared the industrial period (1861-2005) against this baseline.

Their analysis revealed an increase in the frequency of exceptionally dry or wet conditions deviations in streamflow and soil moisture.

Overall, they saw that the global land area experiencing deviations has nearly doubled compared with pre-industrial conditions.

Vili Virkki, a doctoral researcher at Aalto University, said: We found that exceptional conditions are now much more frequent and widespread than before, clearly demonstrating how human actions have changed the state of the global freshwater cycle.

(Photo by Artem Podrez via Pexels)

In their study, the researchers were able to explore geographical differences in these deviations.

They found that exceptionally dry streamflow and soil moisture conditions became more frequent in many tropical and subtropical regions, while many boreal and temperate regions saw an increase in exceptionally wet conditions, especially in terms of soil moisture.

They also found that there were more complex patterns in many regions with a long history of human land use and agriculture.

For example, the Nile, Indus and Mississippi River basins have experienced exceptionally dry streamflow and wet soil moisture conditions, indicating changes driven by irrigation.

Dr. Miina Porkka said: Using a method thats consistent and comparable across hydrological variables and geographical scales is crucial for understanding the biophysical processes and human actions that drive the changes were seeing in freshwater.

The team hopes that their findings will better inform future research on changes in the freshwater cycle.

Associate Professor Matti Kummu added: Understanding these dynamics in greater detail could help guide policies to mitigate the resulting harm but our immediate priority should be to decrease human-driven pressures on freshwater systems, which are vital to life on Earth.

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Freshwater resources at risk thanks to human behavior - Sunnyside Sun