University of Melbourne hydrology expert, Dongryeol Ryu, alongside his colleague Ki-Weon Seo, uncovered surprising data during a train journey to Ryu’s family home. Upon reaching a station due to technical issues, Seo decided to work on his computer, leading to a discovery that caught their attention: data indicated a significant depletion of Earth’s terrestrial water reserves.
Initially dismissing it as a possible model error, Ryu and Seo spent a year verifying their findings. Eventually, they confirmed the concerning discovery. Their paper, recently published in the journal Science, reveals that global warming has extensively reduced water storage in various terrestrial reserves such as soil, lakes, rivers, and snow, posing long-term risks to agriculture and contributing to rising sea levels.
The study presents alarming statistics: Earth’s soil moisture has decreased by over 2,000 gigatons in the past two decades—surpassing Greenland’s ice loss from 2002 to 2006. Increased instances of droughts, rising global seas, and shifts in the Earth’s pole were also noted during this period. Ryu and colleagues utilized multiple data sources to confirm these patterns, highlighting an important agricultural truth: even after intense rainfall following a drought, the underground water reservoirs might not have replenished.
“It appears lands have lost their ability to return to prior states,” commented Ryu. This recovery would largely depend on human interventions in tackling climate change and altering water use practices. As the planet warms, plants require more water, and irrigated agriculture continues consuming water resources unsustainably. Meanwhile, greenhouse gas emissions persist with insufficient efforts to counteract their effects.
According to Katharine Jacobs, an environmental science professor from the University of Arizona not involved with the study, long-term climate changes need to be considered. While they might reverse some of these trends, such changes are unlikely to occur soon. Greenhouse gases are expected to drive global warming into the future, indicating that increased evaporation and transpiration rates will persist.
The researchers also found that the alteration in Earth’s moisture levels contributes to a slight wobble in the planet’s rotation. Luis Samaniego, from the University of Potsdam, expressed excitement about this interdisciplinary puzzle. However, he emphasized that detecting such planetary symptoms, akin to observing an arrhythmia in an electrocardiogram, is a crucial signal for action.
Ignoring these signs, much like neglecting a doctor’s advice, is a risk we are currently facing, he warned.