Integrating renewable energy into power grids at scales needed to mitigate rising atmospheric greenhouse gas concentrations and global warming requires reliable storage—and lots of it. This requirement results from variabilities in the wind and incoming solar radiation that supply most of this energy. Increasingly advanced batteries are the favored means for supplying this storage.
Enter lithium, whose light weight, high electrochemical potential, and high charge-to-weight ratio make it desirable for use in batteries for everything from electronic gadgets to vehicles to power grids. Demand for such batteries has driven rapid growth in the global production of lithium: An estimated 180,000 tons was produced in 2023, compared with about 35,000 a decade earlier.
The hydrological community is paying limited attention to many water-related scientific questions in the Lithium Crescent and the Qaidam Basin.
Lithium is primarily mined from the hard rock mineral spodumene—in Australia, for example—and from brine from dried salt lakes in regions such as South America’s “Lithium Crescent” (LC) and China’s Qaidam Basin (QB). In those two areas, local residents as well as the press, governmental agencies, and nongovernmental organizations are devoting growing attention to water and environmental problems related to brine mining, and tensions with mining companies are becoming more public.
However, the hydrological community is paying limited attention to many water-related scientific questions in the LC and the QB. These questions involve the natural connectivity and transport of regional water resources and how climate and mining operations are affecting their quantity and quality. Hydrologists, hydrometeorologists, and hydrogeologists, using established technologies and surveying methods and working in consultation with residents, governments, and mineral extraction industries, should work to answer these questions and provide a more holistic picture of how brine mining can be made more sustainable.
Lithium from a Crescent and a Bowl
The LC and the QB—located amid the world’s second-largest and largest plateaus, respectively—are arid endorheic basins, meaning they are hydrologically disconnected from the ocean. Numerous salt lakes exist in both regions, with surface areas ranging from 1 to 10,000 square kilometers in the LC and from less than 1 to more than 600 square kilometers in the QB. The lakes get freshwater from streamflow originating from glaciers, snow, and rainfall in adjacent mountains and from groundwater fed by streamflow and precipitation. The main way for water to leave these basins is by evapotranspiration, which over time concentrates mineral salts in deposits in the basin floor, making brine mining possible.
Brine-based lithium sources in the border region of Bolivia, Argentina, and Chile in the Andes Plateau (Figure 1, left)—the so-called Lithium Crescent (a smaller area within the LC is commonly known as the Lithium Triangle)—account for about 53% of the world’s known lithium reserves [Steinmetz and Salvi, 2021]. This region also produces about a third of the world’s lithium compounds.
China, meanwhile, holds about 6.5% of known lithium reserves and contributed about 18% of the global production of lithium compounds in 2023. Several brine-mining operations in China are performed in the country’s “Treasure Bowl”—the Qaidam Basin of Qinghai Province in the northern Tibetan Plateau (Figure 1, right). In 2023, 21.2% of China’s total lithium carbonate production was from the QB [Qinghai Bureau of Statistics, 2023].
The QB produces not only lithium compounds but also potash, fossil fuel, sodium chloride, and other resources that contribute greatly to China’s industry and agriculture. Potash produced in the QB in 2023, for example, accounted for 69.4% of China’s total production of the resource and 6.5% of the world’s potash production (figures calculated on the basis of data from the Qinghai Bureau of Statistics [2023] and from the U.S. Geological Survey).
More Demand amid Changing Conditions
The LC and QB regions receive similar amounts of precipitation—with average annual totals of about 170–180 millimeters—which falls primarily in their respective summers, but whereas precipitation is decreasing slightly in the LC, it is gradually increasing in the QB (Figure 2). The LC is also warmer and more humid on average and exhibits much higher potential evapotranspiration than the QB, yet temperatures in both are increasing.
Water storage is predicted to diminish because warming may reduce glaciers and snow in both regions, and these changes could enhance streamflow variability.
These climate trends are projected to continue in the coming decades, and the climate changes will have consequences for water resources. Water storage is predicted to diminish because warming may reduce glaciers and snow in both regions, and these changes could enhance streamflow variability and alter streamflow regimes. Together with the warming, decreasing precipitation will exacerbate drought conditions in the LC. In the QB, increasing precipitation and melting of glaciers and snow will likely cause more compound extreme events similar to catastrophic floods that occurred in the region in 2010 [Ma and Xu, 2011] and 2022. These floods damaged brine fields, dams, and infrastructure and caused more than $10 million in economic losses.
Meanwhile, the brine-mining industry has been booming in recent decades in both regions. And exploitation of resources, especially lithium, is expected to intensify in the near future, following the recent trend.
To extract the desired materials, miners drill holes in salt flats and pump mineral-rich brine to the surface. The brine is left to evaporate for about 12–18 months, during which about 90% of the original water evaporates. Remaining material is then collected and processed into sellable mineral products. This process of pumping brine and enhancing evaporation at the surface disrupts natural local hydrological cycles. Furthermore, freshwater is needed throughout the processing stage to help purify chemical compounds.
In recent years, reports have connected brine mining to waste generation, water and soil contamination, landscape change, and flora and fauna degradations, as well as to major problems related to water quantity and quality. Conflicts and tensions between local people and mining companies in the Tibetan Plateau and the LC related to reduced water resources and contaminated groundwater and streamflow have also been reported [Marconi et al., 2022; Giglio, 2021].
Studies are documenting effects on ecosystems as well. For example, reductions in some Andean flamingo populations correlate with a lowered groundwater table [Gutiérrez et al., 2022], and cyanobacteria populations that feed Andean flamingos are decreasing in lagoons near Salar de Atacama in Chile because of water consumption and pollution caused by lithium extraction [Gutiérrez et al., 2018].
The amount of water used in brine-mining operations can vary depending on weather, mineral concentrations, and the technology used, but for the LC, researchers have estimated that about 100,000–800,000 liters of water are needed per metric ton of lithium extracted [Vera et al., 2023]. No such estimate exists for the QB, but the thriving mining industry there is also increasing water demand.
In the southern QB, industrial water usage increased from 90 million cubic meters in 2000 to 383 million cubic meters in 2019, respectively accounting for 10.2% and 40.8% of total water consumption in the region in those years [Han et al., 2023]. In 2016, water diversion facilities and channels were constructed to transport water from nearby subbasins to brine fields and cities to meet increasing demand. In December 2023, three major brine-mining factories in the QB breached their water use quotas by illegally pumping groundwater and extracting water from protected wetlands and lakes to meet their production demands. These actions were publicly criticized by China’s Ministry of Ecology and Environment, which ordered the factories to stop pumping water illegally.
Illuminating the Hydrology Around Brine Mining
We have limited knowledge of brine lakes’ role in regional hydrological cycles or about how the expansion of brine-mining operations to feed demand for lithium may alter this role.
Like the ocean and other pools of water below, on, and above Earth’s surface, the world’s brine lakes are players in their regional hydrological cycles. However, we have limited knowledge of brine lakes’ role in these cycles or about how the expansion of brine-mining operations to feed demand for lithium may alter this role.
Several overarching questions confront hydrologists: How and to what extent does brine mining affect the various pools and fluxes (e.g., groundwater recharge, diverted streamflow, evaporation) of the regional hydrological cycle? How does surface runoff from surrounding mountains reach groundwater reservoirs? And how are these reservoirs connected beneath the desert basins where brine lakes occur? What are the ages and chemical compositions of this groundwater? Addressing these questions will inform knowledge of both the quantity and quality of available water resources, which in turn will help decisionmakers allocate water fairly to different sectors and track and protect water quality during brine mining.
Further, because the LC and the QB are experiencing similar warming but different precipitation trends—and their respective regional water cycles may thus be affected differently by the changing climate—hydrologists should explore questions related to these differences. How are glaciers and snow in these regions responding to warming paired with more (or less) precipitation? And how do streamflow regimes (comprising the magnitudes, timings, frequencies, and durations of both high and low flows) respond to changes in glaciers, snow, and precipitation? What mechanisms drive extreme events such as drought and flooding in these regions? Answering these questions will shed light on how climate change is affecting scarce water resources in the LC and QB and can inform mitigation efforts to conserve these resources.
Investigating all these questions requires a variety of approaches. In situ measurements of precipitation, evaporation, glaciers, and snow, as well as of groundwater, lakes, rivers, and soils, are needed to determine the availability and quality of water resources in specific locations in the LC and QB. Analyses using stable isotopes and tracers can help determine the sources and ages of water on and below the ground surface. Satellite observations of how landscape variables, such as desertification, lake area, glaciers and snow, soil moisture, and vegetation, are changing will help track effects of climate change and brine mining on water resources and ecosystems. We will also need hydrogeological modeling studies to understand surface hydrology and groundwater storage and movement, and how they are affected by surface runoff in the LC and QB. (In situ measurements are further required to validate satellite and modeling studies.)
Furthermore, collaborations among researchers from both regions should be pursued to enable detailed comparisons and illuminate differences and commonalities in the water issues of each. Such collaborations would also facilitate sharing of research best practices and potential policy solutions with respect to brine mining and water resources.
Involving All Stakeholders for a Better Outcome
Brine mining will be sustainable only when operations, from cradle to grave, use water efficiently; minimize harm to the environment, ecosystems, and communities; and compensate for damage.
Water resources in the LC and QB are already stressed by virtue of their locations amid the world’s highest deserts and because of changing climatic conditions. Brine mining to help supply lithium and other raw materials for renewable energy transitions may exacerbate this stress. This mining will be sustainable only when operations, from cradle to grave, use water efficiently; minimize harm to the environment, ecosystems, and communities; and compensate for damage when it does occur.
Combining multiple scientific approaches to study regional hydrology will produce holistic and comprehensive knowledge of water quantity and quality in these areas. But to support the sustainability of brine mining and water resource management in the LC and QB, scientists must share the information and answers gleaned from these approaches with relevant government agencies, mining companies, and local communities through research reports and through conferences and town hall meetings that bring these groups together.
Involving community members will especially help reveal not only the effects on hydrology and ecosystems but also the human toll of mining activities and climate change. And improved communication among these groups will help lawmakers and regulators make and enforce rules to govern responsible mining operations while mitigating negative impacts and meeting community needs.
References
Giglio, E. (2021), Extractivism and its socio-environmental impact in South America: Overview of the “lithium triangle,” Am. Crítica, 5(1), 47–53, https://doi.org/10.13125/americacritica/4926.
Gutiérrez, J. S., J. G. Navedo, and A. Soriano-Redondo (2018), Chilean Atacama site imperilled by lithium mining, Nature, 557, 492, https://doi.org/10.1038/d41586-018-05233-7.
Gutiérrez, J. S., et al. (2022), Climate change and lithium mining influence flamingo abundance in the Lithium Triangle, Proc. R. Soc. B, 289, 20212388, https://doi.org/10.1098/rspb.2021.2388.
Han, J., et al. (2023), The potential analysis of rain-flood resources in the Golmud river catchment based on climate change and human interventions, Qaidam basin [in Chinese], J. Salt Lake Res., 31(4), 30–38.
Ma, S., and L. Xu (2011), 2010 Golmud River flooding analysis, Qinghai Sci. Technol., 1, 38–41.
Marconi, P., F. Arengo, and A. Clark (2022), The arid Andean plateau waterscapes and the lithium triangle: Flamingos as flagships for conservation of high-altitude wetlands under pressure from mining development, Wetlands Ecol. Manage., 30, 827–852, https://doi.org/10.1007/s11273-022-09872-6.
Qinghai Bureau of Statistics (2023), Statistics of national economy and social development in 2023 [in Chinese], m.yicai.com/news/102000260.html.
Steinmetz, R. L. L., and S. Salvi (2021), Brine grades in Andean salars: When basin size matters—A review of the Lithium Triangle, Earth Sci. Rev., 217, 103615, https://doi.org/10.1016/j.earscirev.2021.103615.
Vera, M. L., et al. (2023), Environmental impact of direct lithium extraction from brines, Nat. Rev. Earth Environ., 4, 149–165, https://doi.org/10.1038/s43017-022-00387-5.
Author Information
Lan Cuo (lancuo@itpcas.ac.cn), State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing; also at University of Chinese Academy of Sciences, Beijing
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