The Earth’s freshwater reserves experience a sudden decline starting in May 2014 and have remain persistently low, as per findings by an international team of scientists utilising NASA-German satellites.
Observations from the Gravity Recovery and Climate Experiment (GRACE) mission reveal a significant reduction in freshwater store on land, including lakes, rivers, and underground aquifers.
This study, publish in Surveys in Geophysics, suggests this shift may indicate a transition to drier conditions across the continents.
Between 2015 and 2023, terrestrial freshwater levels find to be 290 cubic miles below the average recorded from 2002 to 2014, according to Matthew Rodell, a hydrologist at NASA’s Goddard Space Flight Center.
This equates to over twice the volume of Lake Erie. Contributing factors include droughts and increased reliance on groundwater for agriculture and urban needs, which depletes reserves faster than they can be replenish.
A 2024 United Nations report on water stress highlight the societal risks of diminish water supplies, including famine, poverty, and reliance on unsafe water sources.
Research indicates that rising global temperatures may be exacerbating freshwater loss.
Michael Bosilovich, a meteorologist at NASA Goddard, explain that warming intensifies evaporation and increases the atmosphere’s capacity to retain moisture, leading to extreme rainfall events.
As total annual precipitation remains steady, prolong dry spells between these events reduce soil absorption, worsening drought conditions.
Satellite data show that global freshwater did not recover after a significant El Niño event between 2014 and 2016, which had cause shifts in atmospheric patterns and widespread droughts.
Matthew Rodell said that 13 of the 30 most severe droughts since 2002 occurre after 2015.
Although the link to climate change is not definitive, the concurrent timing with record-high global temperatures has raise concerns about the future stability of freshwater resources.
Hydrologist Susanna Werth from Virginia Tech, unaffiliate with the study, emphasise the challenges in predicting long-term outcomes due to uncertainties in climate models.
But, the current trends are being closely monitor for further implications.
