By Caroline Catherman
Chile’s seemingly barren Salar de Atacama hides a thriving ecosystem in shallow salt lakes that teem with microorganisms, green grasses, and flamingos, among the diverse lifeforms. The Lickan Antay and other indigenous communities who live along the desert cannot and will not separate their identity from the land they live on.
“The indigenous people understand these [organisms] to be their ancestors. Their grandfathers come from these lakes. The people … understand themselves to be very intrinsically part of it,” said Jessica Ng, a Scripps Institution of Oceanography Ph.D. student.
But the desert hides something else that many indigenous people wish had been kept a secret: It is the world’s largest source of lithium, which is expected to increase in demand as people increasingly mine it for electric vehicle batteries.
For decades, the Chilean government’s Superintendence of the Environment has given companies environmental permits to pump limited amounts of water from underground aquifers, evaporate it, and extract lithium from the leftover brine. This pumping potentially disturbs ancient ecosystems, indigenous people’s ancestral grounds, and, in some cases, the desert’s limited water resources.
Concern about water levels was compounded in 2016, when Chilean officials charged one company, the Chilean Chemical and Mining Society (SQM), with pumping more brine than its environmental permit allowed. Though a group of indigenous people won an environmental lawsuit against the corporation in 2019, requiring it to greatly improve its mining process, the group wants extraction to end entirely, according to Reuters.
Now, Ng, in fieldwork put on hold by the pandemic, is researching how much water was under Chile’s Salar de Atacama before the mining started. She thinks that her research could provide evidence that these companies are drying up water tables in one of the world’s driest deserts, and hopes that this evidence could help convince the government to revoke mining permissions.
“We need to avoid … supposed solutions that continue these dynamics of constant extraction, production, consumption and pollution,” Ng said, “Instead of just switching from doing that with fossil fuels to doing that with other materials.”
Ng will determine the previous depths of water tables with in a new method dubbed “blow-you-away interesting” by Richard Alley, Pennsylvania State University geologist and MC of the Comer Climate Conference where Ng spoke this October.
She is measuring the proportion of heavier and lighter versions of gases such as Krypton and Xenon that dissolve into groundwater from dry soil’s air.
The proportion of heavy versions of these gases increases the deeper you look underground. So if Ng finds a low proportion of heavy gases in the water, she will know that the dry soil’s air did not reach far underground; this means the water level was higher. If Ng finds a high proportion of heavy gases, she will know that the dry soil reached far underground, so the water level was lower.
She can then connect these measurements with estimates of age to determine when the water was at a certain level, and compare that to today’s levels and the accelerating rate of water extraction.
Ng thinks that she will find a decrease in the water levels compared to the thousands of years before companies started mining lithium. Mining companies claim that extracting water from one part of the salar will not affect water in other parts, where communities live and farm, said Ng. But she added that there is no evidence for that. In fact, Ng said, aquifer maps suggest that the waters are connected, so taking water from one area will affect another area.
Her research will add to the work of colleagues such as Datu Buyung Agusdinata, senior sustainability scientist at the Arizona State University Global Institute of Sustainability and Innovation, who found through analysis of satellite images that areas of the Atacama Desert were drying in correlation with mining, and found that protests against the industry were increasing.
The key to reforming lithium mining, he said, is to put pressure on major companies and government officials.
“Even when the locals voice their concerns, it’s picked up by the media, and then it’s becoming a new, considerable force or pressure that companies like Tesla cannot ignore,” he said.
Advocates could also encourage companies to explore alternatives to lithium, like magnesium, said Alley at the conference. New battery research is seeking alternatives to lithium since lithium-ion batteries in many consumer electronics pose a fire risk.
“People who are figuring out ways to build batteries that use less lithium and more magnesium—because magnesium is way, way, way more common—are hugely important,” Alley said.
Caroline Catherman covers health, environment, and science at Medill. You can follow her on Twitter at @CECatherman.