“100-Year Floods: NASA Unveils Alarming Human Impact on the Global Water Cycle”

A newly released study by NASA researchers has identified extraordinary alterations in the global water cycle as a result of human influence. These modifications include a decrease in groundwater levels and significant occurrences such as the heightened frequency of “100-year floods.” 

Numerous changes stem from human endeavors like farming and may impact ecosystems and water governance, especially in specific areas. 

“Our data assimilation revealed that human influence on the global water cycle is more pronounced than previously thought,” stated Sujay Kumar, a research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and a co-author of the paper, which appeared in the Proceedings of the National Academy of Sciences. 

These transformations have worldwide repercussions. Strategies for managing water—such as the design of flood infrastructure and drought indicators for early warning systems—are generally based on the belief that the water cycle operates within a predictable range, as explained by Wanshu Nie, a research scientist at NASA Goddard and the principal author of the study. 

“This assumption may no longer be accurate for certain regions,” Nie noted. “We aspire to use this research to enhance how we evaluate water resource variability and strategize for its sustainable management, particularly in regions where these alterations are significantly visible.” 

An instance of human influence on the water cycle can be observed in North China, where an ongoing drought remains. Despite this, vegetation continues to thrive in various locations, in part because farmers are extracting supplemental water from groundwater reserves for irrigation purposes, as Kumar clarified. These interconnected human activities frequently induce intricate alterations within other components of the water cycle, like evapotranspiration and runoff. 

Nie and her colleagues concentrated on three categories of shifts within the water cycle: first, a trend, such as decreasing water levels in a groundwater reserve; second, a seasonal change, like an earlier beginning of the growing season or premature snowmelt; and third, a transformation in extreme events, like the increased occurrence of “100-year floods.” 

The researchers utilized remote sensing data from 2003 to 2020, gathered from various NASA satellites, which includes the Global Precipitation Measurement mission satellite for rainfall information, a soil moisture dataset from the European Space Agency’s Climate Change Initiative, along with the Gravity Recovery and Climate Experiment satellites for terrestrial water storage data. They also employed the Moderate Resolution Imaging Spectroradiometer satellite instrument to observe vegetation well-being. 

“This publication integrates several years of our team’s work on developing satellite data analysis capabilities, allowing us to accurately model continental water fluxes and storage globally,” remarked Augusto Getirana, a research scientist at NASA Goddard and co-author of the study. 

The outcomes imply that Earth system models utilized for forecasting future global water cycles should adapt to encompass the ongoing impacts of human activities. With enhanced data and improved models, water resource managers and producers can better comprehend and prepare for the “new normal” of their regional water conditions, Nie concluded.