Humans have driven Earth’s freshwater cycle out of stable state: Study

PTI

New Delhi, March 4

Human activity has pushed the Earth’s freshwater resources far beyond the stable conditions that prevailed before industrialisation, a study has found.

The findings, published in the journal Nature Water, show that the updated planetary boundary for freshwater change was surpassed by the mid-twentieth century.

This is the first time that global water cycle change has been assessed over such a long timescale with an appropriate reference baseline, the researchers said.

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, they said.

The international team calculated monthly streamflow and soil moisture at a spatial resolution of roughly 50x50 kilometres using data from hydrological models that combine all major human impacts on the freshwater cycle.

The researchers determined the conditions during the pre-industrial period (1661-1860). They then compared the industrial period (1861-2005) against this baseline.

The analysis showed an increase in the frequency of exceptionally dry or wet conditions—deviations in streamflow and soil moisture.