The transition to a clean-energy economy, essential for addressing climate change (UN SDG 7), presents significant sustainability challenges centered on the intensified exploitation of critical minerals. The demand for these minerals, including copper, lithium, cobalt, nickel, and rare-earth elements (REEs), has surged, with mineral requirements for clean-energy technologies increasing by 50% since 2010, and projected to grow substantially more for specific elements like lithium, cobalt, and REEs. This heightened demand brings forth a complex web of environmental, social, and resource management issues.
The intensification of mineral exploitation presents significant environmental challenges that need urgent attention. One of the most pressing issues is water resource depletion, particularly under the framework of Sustainable Development Goal 6, which emphasizes the importance of clean water and sanitation. Mining is an incredibly water-intensive process, with alarming statistics highlighting that half of the current copper and lithium production takes place in water-stressed regions.
For instance, extracting just one ton of lithium demands approximately 500,000 liters of water, an amount that can satisfy the daily needs of 850 people in the United States or 10,000 individuals in water-scarce regions like Chile. This high water demand exacerbates existing water stress, but some mining operations in Chile are exploring methods such as recovering water from tailings and utilizing seawater to alleviate this issue.
Pollution is another critical concern associated with mining activities. They produce vast amounts of waste rock and tailings, leading to concerns about air, water, and land pollution. Tailings ponds and acid mine drainage (AMD) pose significant risks, as AMD is the acidic, sulfate-rich runoff generated from sulfide mineral mining. This hazardous effluent can persist long after a mine has closed, thereby contaminating water sources and harming aquatic ecosystems.
Moreover, the expansion of mining operations results in considerable land use changes, which threaten ecosystems and biodiversity. This situation directly impacts Sustainable Development Goal 15, which focuses on life on land, raising questions about the "cleanliness" of so-called clean energy sources that rely on these minerals.
In addition to these environmental challenges, the mining and processing of certain critical minerals lead to the concentration of naturally occurring radioactive materials, creating a waste concern known as Technologically Enhanced Naturally Occurring Radioactive Material (Tenorm). For example, during the production of copper, activities such as in-situ leaching and solvent extraction have been found to concentrate these radioactive substances, posing both environmental and health risks. The U.S. EPA has raised alarms about the potential for radionuclides to leach from tailings piles, further emphasizing the hazards associated with these operations.
The risks associated with tailings management are also paramount, particularly considering the increasing volume of tailings generated due to the mining of lower ore grades. This rise heightens the probability of failures in tailings storage facilities (TSFs). Catastrophic events, such as the dam collapses at Mount Polley in Canada and Fundão in Brazil, released enormous quantities of toxic waste, resulting in widespread environmental damage and affecting nearby human settlements.
The challenges are particularly acute for copper and rare earth elements (REEs). While global copper reserves remain substantial and shortages are not a significant concern thanks to recycling, the mining of copper predominantly conducted in Chile creates exceedingly large quantities of waste, with Chile producing around 800 million metric tons of tailings annually.
The environmental footprints associated with both pyrometallurgical and hydrometallurgical copper production processes include emissions of sulfur dioxide, although these are often converted into sulfuric acid, along with the generation of Tenorm-containing waste like raffinate.
As for rare earth elements, demand is projected to grow sixfold by 2040, with China currently dominating global production. Many REE deposits are relatively modest in size, with heavy rare earth elements being particularly scarce. The processing of these minerals involves a series of complex steps, including flotation, gravity and magnetic separation, followed by intricate chemical processes such as acid leaching and solvent extraction to individualize the rare earth elements. These methods generate waste and may involve hazardous chemicals, compounding the environmental impacts associated with their extraction and processing..
While the transition to clean energy is vital, the sourcing of its material foundation must be managed sustainably to avoid merely shifting environmental and social burdens. The issues are complex, interlinked with UN SDGs, and demand concerted efforts from industry, governments, researchers, and consumers.
The transition to clean-energy technologies, essential for addressing climate change and achieving UN Sustainable Development Goal (SDG) 7 (Affordable and Clean Energy), has paradoxically introduced a new set of significant sustainability challenges centered around the greatly increased demand for critical minerals.
The mineral requirements for these technologies have surged by 50% since 2010, with projections indicating a sixfold increase for Rare-Earth Elements (REEs) by 2040 and a twentyfold increase for lithium and cobalt by 2050. This intensified exploitation of minerals like copper (Cu), lithium (Li), cobalt (Co), nickel (Ni), and REEs brings forth a host of interconnected environmental, social, and geopolitical issues.
A primary challenge is the geographical concentration of these critical mineral reserves. For instance, Chile holds about 23% of global copper reserves, while China dominates REE production (70% in 2022) and a significant portion of REE reserves (37%). Similarly, about 46% of cobalt is in Congo, and 44% of nickel is found primarily in Australia and Indonesia.
This concentration makes supply chains vulnerable and creates dependencies, particularly for nations like the USA and those in Europe, which hold very small fractions of these global reserves. This is compounded by the long lead times for mining projects, averaging over 10 years from discovery to production, and potentially longer in regions lacking infrastructure, regulatory frameworks, or facing security issues.
The transition towards a circular economy for critical minerals is currently lagging behind. Although certain materials like copper and nickel are being recycled at rates of 32% and 52% of U.S. consumption, respectively, the recovery of rare earth elements (REEs) from products such as batteries, magnets, and lamps remains very limited. In particular, lithium recycling is still in its infancy, with only 32 companies worldwide engaged in the recycling of lithium batteries.
Several challenges complicate the recycling process. Logistical issues arise when it comes to collecting and dismantling end-of-life products. Additionally, the intricate designs of many items, such as smartphones which incorporate numerous critical minerals, complicate the recovery efforts. There is also a pressing need for technological innovations to make the recovery process both efficient and economically viable.
Moreover, the e-waste crisis is worsening, with the growing volume of end-of-life consumer products posing significant health risks. In 2019, only 17.4% of e-waste was formally recycled, which is particularly concerning for vulnerable populations in low-income countries that often participate in informal and unregulated dismantling and recycling operations. This situation highlights the urgent need for better recycling solutions in the face of escalating e-waste challenges.
Addressing these sustainability challenges requires a multi-pronged approach. This includes developing more sustainable mining practices, intensifying research and investment in efficient and environmentally sound mineral processing and recycling technologies, and robust water management plans for mine sites, including improved water recovery from tailings and desalination where feasible. Stronger regulatory frameworks for TSFs, AMD control, and the safe utilization of mine waste (with careful consideration of hazards like Tenorm) are essential.
Furthermore, a global effort to improve the collection, dismantling, and recycling of EOL products is crucial to reduce reliance on primary extraction and mitigate the environmental and social burdens of a clean energy transition. Without these measures, the pursuit of clean energy risks perpetuating unsustainable practices and environmental degradation