Have Some Water - While You Can

We live on a water world (despite its name being “Earth”). We, like all life on earth, are water creatures, basically just sacks of water. We drink it, in its various forms (plain, sparking, carbonated, sweetened, flavored, even transformed by a mammal into milk). We use it to grow our crops, to flush our toilets, to water our lawns, to frack our oil, to name a few uses. Yet 97% of Earth’s water is salt water, which we can’t drink without expensive desalination efforts, and most of the 3% that is freshwater is locked up – in icebergs, glaciers, the ground and the atmosphere, etc. Our civilization survives on that sliver of freshwater that remains available to us.

Guess which one is our more likely future. Credit: Microsoft Designer

Unfortunately, we’re rapidly diminishing even that sliver. And that has even worse implications than you probably realize.

A new study, published in Science Advances, utilizes satellite images (NASA GRACE/GRACE-FO) to map what’s been happening to the freshwater in the “terrestrial water storage” or TWS we blithely use. Their critical finding: “the continents have undergone unprecedented TWS loss since 2002.”

Indeed: “Areas experiencing drying increased by twice the size of California annually, creating “mega-drying” regions across the Northern Hemisphere…75% of the population lives in 101 countries that have been losing freshwater water.” The dry parts of the world are getting drier faster than the wet parts are getting wetter.

Credit: Chandanpurkar, et. al.

“It is striking how much nonrenewable water we are losing,” said Hrishikesh A. Chandanpurkar, lead author of the study and a research scientist for Arizona State University. “Glaciers and deep groundwater are sort of ancient trust funds. Instead of using them only in times of need, such as a prolonged drought, we are taking them for granted. Also, we are not trying to replenish the groundwater systems during wet years and thus edging towards an imminent freshwater bankruptcy.”

As much as we worry about shrinking glaciers, the study found that 68% of the loss of TWS came from groundwater, and – this is the part you probably didn’t realize – this loss contributes more to rising sea levels than the melting of glaciers and ice caps.

This is not a blip. This is not a fluke. This is a long-term, accelerating trend. The paper concludes: “Combined, they [the findings] send perhaps the direst message on the impact of climate change to date. The continents are drying, freshwater availability is shrinking, and sea level rise is accelerating.”

Yikes.

“These findings send perhaps the most alarming message yet about the impact of climate change on our water resources,” said Jay Famiglietti, the study’s principal investigator and a professor with the ASU School of Sustainability. 

We’ve known for a long time that we were depleting our aquifers, and either ignored the problem or waved off the problem to future generations. The researchers have grim news: “In many places where groundwater is being depleted, it will not be replenished on human timescales.” Once they’re gone, we won’t see them replenished in our lifetimes, our children’s lifetimes, or our grandchildren’s lifetimes.

Professor Famiglietti is frank: “The consequences of continued groundwater overuse could undermine food and water security for billions of people around the world. This is an ‘all-hands-on-deck’ moment — we need immediate action on global water security.”

If all this still seems abstract to you, I’ll point out that much of Iran is facing severe water shortages, and may be forced to relocate its capital. Kabul is in similar straits. Mexico City almost ran out of water a year ago and remains in crisis. Water scarcity is a problem for as much as a third of the EU, such as in Spain and Greece. And the ongoing drought in America’s Southwest isn’t going any anytime soon.

Propublica has a great story on the study and its implications, with some killer illustrations. It points out that the study suggests the middle band of Earth is becoming less habitable, and “…these findings all point to the likelihood of widespread famine, the migration of large numbers of people seeking a more stable environment and the carry-on impact of geopolitical disorder.”

As Aaron Salzberg, a former fellow at the Woodrow Wilson Center and the former director of the Water Institute at the University of North Carolina, who was not involved with the study, told ProPublica: “Water is being used as a strategic and political tool. We should expect to see that more often as the water supply crisis is exacerbated.”

That. Is. Going. To. Be. A. Problem!

We can’t see the loss of groundwater, but, increasingly, we can see the impacts of it. A study published in May used satellite data to show that all – that’s all – of the 28 largest U.S. cities are sinking as a result of land subsidence, mostly due to groundwater extraction. They’re sinking by 2 to 10 millimeters per year, and: “In every city studied, at least 20 percent of the urban area is sinking — and in 25 of 28 cities, at least 65 percent is sinking.”

Sinking quantified. Credit: Ohenhen, et. al. 

Leonard Ohenhen, the study’s lead author, notes: “Even slight downward shifts in land can significantly compromise the structural integrity of buildings, roads, bridges, and railways over time," Principal investigator Associate Professor Manoochehr Shirzaei adds: "The latent nature of this risk means that infrastructure can be silently compromised over time with damage only becoming evident when it is severe or potentially catastrophic. This risk is often exacerbated in rapidly expanding urban centers."

If “2 to 10 millimeters per year” doesn’t scare you, you only need look at Central Valley (CA), which has been sinking about an inch per year over the last 20 years – and is now some 30 feet lower than a hundred years ago. That you’ll notice.  

Professor Famiglietti and his coauthors retain some hope:

While efforts to slow climate change may be sputtering (72, 73), there is no reason why efforts to slow rates of continental drying should do the same. Key management decisions and new policies, especially toward regional and national groundwater sustainability, and international efforts, toward global groundwater sustainability, can help preserve this precious resource for generations to come. Simultaneously, such actions will slow rates of sea level rise.

As evidence that smart water management plans can have an impact, Los Angeles uses less water now than in 1990, despite having a half million more residents.

This problem isn’t something we can wave our hands at and call “fake news.” This isn’t a “theory” like critics try to claim climate change is. We can measure the loss of groundwater; we can measure land subsidence. Professor Famiglietti warns: “We can’t negotiate with physics. Water is life. When it’s gone, everything else unravels.”