The world’s largest groundwater basins are quickly depleting according to new satellite imagery retrieved from NASA’s Gravity Recovery and Climate Experiment.
The two studies coming from a consortium of researchers are the first to draw on this type of data to analyze the Earth’s water resources. Groundwater losses are assessed for the first time using the data from the twin GRACE NASA satellites.
The role of the GRACE satellites is to measure the fluctuation of our planet’s gravity, which is highly impacted by the weight of groundwater.
What the studies are drawing attention to is the fact that we are quickly depleting the water resources we have without even knowing how much there is left to consume. This is the greatest issue facing groundwaters today.
That while there are studies such as these which know that the greatest basins of the world are draining, there is no accurate data on how much water there is still left for humanity to consume.
The issues and the findings of the study are extensively debated in the paper published in the Water Resources Research journal.
Jay Famiglietti, one of the researchers involved in the studies and water scientist for NASA Jet Propulsion Laboratory commented in light of the findings:
“Available physical and chemical measurements are simply insufficient. Given how quickly we are consuming the world’s groundwater reserves, we need a coordinated global effort to determine how much is left.
The first study looked at the 37 largest groundwater basins, comparing images and data from 2003 to 2013. Results showed that eight out of 37 aquifers are overstressed. This means that while depletion is happening at an accelerated rate, there is little natural offset that could turn the situation around. Typically, these are found in the world’s driest regions and are heavily impacted by climate change and population growth.
Following these eight, another five aquifers were either extremely stresses or highly stressed. This meant that there were still source that could replenish the basins.
As it was probably expected, the worst case scenarios are to be found in those regions where environmental factors are highly stressful or where tensions occurs, be it from a socioeconomic perspective or political.
To this extent the two studies are making a point to the need for increasingly active management of groundwater basins and thorough knowledge on what water resources are still available.
One example that indicates the uncertainty of existing data is the aquifer system of Northwest Sahara. In the case of the overstressed aquifer, the projected time until it will be fully depleted varies according to different sources from 10 years to 21,000 years.
Adding to the problem of correctly assessing the groundwater basins is the fact that no measurements are made as to how much water they actually contain.
According to the study, the most overstressed aquifer in the world is also the water source for 60 million people. This is the Arabian Aquifer System.
Following, the Indus Basin aquifer, water source for India and Pakistan is the world’s second overstressed, while the third place is occupied by the Murzuk-Djado Basin.
Image Source: NASA