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Giant aquifers, like those depicted in this map, are rapidly being depleted by man, and that phenomenon has greatly influenced the pace of sea level rise. |
But one of the biggest drivers of sea level rise is coming from a surprising source: Pumping groundwater to the surface for drinking water, irrigation and industry.
"So much groundwater is now being pumped that it is filling the oceans as it drains off land, becoming one of the largest drivers of global sea level rise."
The result is vast parts of Earth's land masses are drying out, according to an ambitious new study.
"More than anything, Earth is being slowly dehydrated by the unmitigated mining of groundwater, which underlies vast proportions of every continent. Nearly 6 billion people, or three quarters of humanity, live in the 101 countries that the study identified as confronting a net decline in water supply. - portending enormous challenges for food production and a heightened risk of conflict and instability."
This comes from a study led by Hrishikesh Chandanpurkar, an earth systems scientist working with Arizona State University. The research was published recently in the journal Science Advances. The study looks at most of the Earth, but excludes the fresh water ice sheets of Antarctica and Greenland
There's even more bad news in the research: The loss of water through groundwater pumping is happening as many areas are growing drier due to climate change.
The study notes that with climate change, some areas of Earth are getting drier while others are getting wetter. However, drying regions are expanding quickly while places that have been getting wetter are shrinking.
Deep, high quality aquifers are actually widespread, lying beneath one third of the planet. The aquifers are under about half of Africa, Europe and South Africa. They took millions of years to form and would take thousands of years to refill.
But with us humans, a significant amount of that water is taken from underground, given over to irrigation or industry, then runs off, eventually finding its way to oceans.
This loss of water from aquifers has gotten so great, that it is one of the largest causes of sea level rise. "Moisture lost to evaporation and drought, plus runoff from pumped groundwater, now outpaces the melting of glaciers and the ice sheets of either Antarctica or Greenland as the largest contributor of water to the oceans," ProPublica reports.
The study was done using 22 years of data from NASA's Gravity Recovery and Climate Experiment, or GRACE satellites. Images from the satellites measure changes in th mass of the Earth and can be used to estimate its water content.
As ProPublica reports, study co-author Jay Famiglietti has for two decades used GRACE data to determine where aquifers were declining.
Chandanpurkar and Famiglietti began to wonder what all this meant regarding all the water available on the continents. So the study, really an inventory of all land-based water contained in glaciers, rivers and aquifers, set out to see how things were changing.
Spoiler: It's changing fast.
For instance, scientists and water managers were well aware that aquifers in the U.S. Southwest were receding. Their research also showed a "creeping disaster" of accelerating drying in aquifers spreading out from the Southwest into Texas, and down into Mexico. The same pattern was noted in Europe, the Middle East, North Africa and parts of Asia.
So, draining the aquifers looms as a crisis for crops and industry, which would die out with the drying out of aquifers. Even if crops can still grow, shipping them out will be problematic, since the water from the aquifers is raising sea levels. Which floods ports and such. Not to mention important crop-growing regions like the Nile and Mekong deltas.
One the groundwater is lost to the seas, the only ways to get it back are through expensive and inefficient coastal desalination plants. Or waiting hundreds or thousands of years for rain to replenish desiccated aquifers.
Other research that the climate change is not only warming up the air and the oceans. It's actually starting to extend its tentacles deep underground. The research says ground water is warming up as much as 40 to 50 meters (about 130 to 165 feet) underground.
That underground warming could increase microbial production and allow chemicals such as arsenic, locked away in cold underground rocks, to get released as warming takes hold far below our feet. The warmer groundwater could also bubble up into lakes, ponds and rivers, allowing more damaging algae blooms and killing some aquatic life, as Grist reports.
As climate scientist Peter Gleick notes, drying out aquifers threatens global food production. And food is the foundation for stability. So don't get too smug, America. If you think we have immigration problems, brutal, often unfair and possibly illegal deportations and the political turmoil that comes with all that now, just wait until the groundwater dries up.
Like or not food and climate refugees might well be stampeding toward our borders in the United States. No matter how many walls we throw up, or how many Executive Orders presidents declare.
Water and the lack thereof is already contributing to war and violence, ProPublica notes. The Syrian civl war that began in 2011 started as rural unrest stemming from drought and groundwater depletion. Ukrainian wheat support much o the world, so Russia is targeting that nation's water infrastructure.
There are things we can do to slow or even stop the groundwater depletion, the researchers said. Drip irrigation can cut water use by as much as 50 percent. Arid Israel has used that technique effectively.
When California farmers reduced their use of Colorado River water in 2023 and 2024, Lake Mead rose by 16 feet. People in arid areas can remove lawns in favor of native plants. Cities can recycle a lot of their water.
This is a solvable crises. But work has to start now to get this going.