- Steel and aluminum are two of the world’s most in-demand materials, feeding numerous sectors — including construction and transportation — with demand forecast to grow in the coming decades.
- Aluminum in particular will see a major surge in demand to supply the clean energy transition, with the metal used in lightweight electric vehicles and renewable infrastructure.
- But both these metals already carry a heavy environmental burden. Mining causes deforestation and toxic pollution with serious human health and social impacts, while refining generates major emissions contributing significantly to the climate crisis.
- Cleaning up these industries and practices is essential, say analysts. A circular economy approach holds promise but comes riddled with challenges and uncertainties.
This is the first part of a two-part story. Part one deals with aluminum and steel impacts; Part two explores circular solutions.
Aluminum and steel are two metals vital to a thriving global industrial economy. And both will be even more in demand in future, as they supply the global energy transition and infrastructure needs in developing countries. But there’s a problem: the mining and processing of these two metals negatively impact at least five of Earth’s nine planetary boundaries, helping put the “safe operating space for humanity” at grave risk.
A major report published in June 2024 by advocacy group Mighty Earth underscores some of these problems: The NGO charted numerous environmental and human health concerns in major bauxite-producing countries around the globe, including Australia, Brazil, Indonesia and Guinea. Bauxite is the principal ore used in alumina production, which is a key ingredient in making aluminum.
“We found … a common thread. In every place bauxite mining is touching right now there seems to be really negative impacts for people and the environment,” says Matthew Groch, senior director of decarbonization at Mighty Earth. Those impacts include deforestation, wildlife loss and often severe health impacts. Groch notes that “There seems to be a lot of pushback from local communities” on new projects as they’re announced.
In Guinea, home to Africa’s largest bauxite reserves, extraction comes with big environmental and social costs, along with allegations of human rights abuses. Mining there has resulted in community exposure to toxic pollution and large dust plumes causing widespread respiratory problems, says Diaby, executive director of the Association for Rural Development and Mutual Aid of Guinea (ADREMGUI), a local NGO. In addition, mining expansion has deprived local people of farmland and access to water, which has resulted in community-industry conflict.
“The places where people have their means of subsistence are impacted. The communities hunt, farm and fish in the forests,” Diaby says, but bauxite is mostly surface mined, so deforestation is rampant. “All those resources are destroyed because of the mining activities.”
Increasing demand for bauxite is creating concern that these impacts will spread to other nations as they look to mine their own reserves, potentially threatening protected areas. In Ghana, for example, environmentalists are fighting proposed bauxite mining in the Atewa Range Forest Reserve, a global biodiversity hotpot. That expansion would have devastating consequences for multiple wildlife species, communities and the water supply for millions of people, they say, pointing to nearby Guinea as an example. Half a world away, the Brazilian Amazon’s riverine peoples have endured similar environmental and health problems at the hands of large bauxite-mining companies.
“We know from the experience across the world that bauxite mining is not only about the site you are mining, but also the road networks, transport services and even infrastructure for the construction works,” says Daryl Bosu, deputy national director at A Rocha Ghana, an NGO based in Ghana. This new infrastructure has a ripple effect, he notes, opening up the forest for other activities such as logging, poaching and bushmeat hunting: “All of that is eventually going to lead to the complete destruction of the forest.”
Steelmaking also has a massive mining footprint, with iron ore and nickel (needed to make steel) stripped from the earth by immense earthmoving machines, and impacting developing countries such as Guinea, Brazil and Indonesia.
Experts note that processing and refining intensifies the damage done by mining, adding pressure to Earth’s “triple crisis” of biodiversity loss, pollution and climate change.
And that’s the terrible conundrum: Both metals will be needed in larger amounts to achieve the rollout of humanity’s sustainable energy, transportation and infrastructure future. Which is why analyzing current and projected benefits and harms along the entire aluminum and steel supply chains is urgently required now to achieve an equitable and sustainable circular economy in the future.
Counting carbon
Alongside cement and concrete, which have their own environmental challenges, steel is a backbone of global industrialization and infrastructure. Though other critical metals will see a huge boom in coming years, steel’s increase is expected to be relatively modest by comparison, yet demand is still expected to increase by about 30% through 2050, predominantly due to expansion in India, Africa and Southeast Asia.
At present, processing the nearly 2 billion metric tons of steel used annually releases around 7% of humanity’s total greenhouse gas emissions and up to 11% of CO2 emissions. And even as cleaner alternative steel production methods come online, the conventional and highly polluting blast furnaces that dominate today will continue relying largely on dirty, carbon emission-intensive metallurgical coal over the next three decades, according to forecasts.
Unlike steel, aluminum production is seen as key to humanity’s energy transition, helping support future greenhouse gas emission reductions in other industrial sectors. As a direct result, an increase in primary demand for aluminum of 40-50% by 2050 is expected, driven in part by heavy use in lightweight electric vehicles, renewable energy infrastructure, and building out energy grids.
Caroline Avan, head of the Natural Resources and Just Energy Transition Programme at the Business & Human Rights Resource Centre, a global NGO, describes aluminum as a “cross-cutting sort of metal” used in the energy transition for EVs, wind turbines and solar power, and her organization lists bauxite in its “transition minerals tracker” that’s seen as a critical mineral by the U.S. and European Union.
At present, aluminum production is responsible for around 2% of human-caused carbon emissions. Projected increases in production will come with a huge uptick in demands for clean electricity to produce it. The vast majority of today’s emissions from aluminum production, as much as 80%, are released when alumina, the material created from bauxite, is refined into aluminum, says Mighty Earth’s Groch.
A widening cloud of toxic, health-harming pollutants
“Steel production is having a big impact on climate change, which is one of the key planetary boundaries,” notes Stephan Pfister, a professor at the Ecological Systems Design Group at ETH Zurich. But release of particulate matter is also “significant,” he adds. Several million premature deaths annually are currently attributed to particulate pollution, according to the WHO.
“You have all types of other emissions coming out of burning of fossil fuels related to steel production,” says Sridhar Seetharaman, vice dean for research and innovation at Arizona State University. “If you look at towns where steel plants or traditional steel mills are located [in the U.S.], they’re often the most polluted [communities].” He cites Gary, Indiana, as a chief example: It boasts the largest steel mill in the U.S. and is also the nation’s most polluted city, according to research by the Sierra Club, an environmental NGO.
In China, the world’s largest steel producer, it’s estimated that pollutants released during iron and steel production caused more than 59,000 premature deaths in 2020 alone, according to a 2024 study. Other research shows how production is linked to emissions of heavy metals, risks of cancer, arsenic contamination and respiratory illness, creating concerns for workers’ health and for nearby communities.
Similarly, the stages of aluminum production can degrade both air and water, entailing major human health impacts, according to research by the Environmental Integrity Project (EIP). The making of petroleum coke for the aluminum refining process along with other industries was responsible for the release of thousands of tons of hydrochloric acid, sulfur dioxide and particulate matter in 2022 in the U.S., an EIP report states.
This pollution problem has led to the aluminum clean energy “paradox,” according to Nadia Steinzor, an EIP research and policy analyst. If production methods aren’t improved now, the expected massive increase in aluminum production to serve the energy transition will exacerbate both environmental and social ills.
Sustainable solutions are needed, from mining to smelting, to make production less harmful for local communities, the environment and climate, Steinzor says: “That’s the inherent aluminum paradox: It’s part of clean energy, but also really dirty.”
Red mud, tailings and other contaminants
Even as the projected increase in aluminum production is likely to worsen transgressions of the climate change, biosphere integrity and novel entity (pollution) planetary boundaries, the mining of its raw material, bauxite, is already negatively impacting the freshwater change and land system change boundaries — and expected to get worse.
The problem is red mud: When bauxite is refined into alumina, a difficult-to-manage toxic residue is left behind known as red mud. And there’s already lots of it in the world: “With about 180 million tonnes produced per year, red mud has amassed to [be] one of the largest environmentally hazardous waste products, with the staggering amount of 4 billion tonnes accumulated on a global scale,” according to a 2024 study. This could climb to 10 billion metric tons by 2050 — contaminating both land and water, especially in the developing world where strong environmental regulations are often lacking.
This global red mud calamity is “vastly underestimated,” says Matic Jovičević-Klug, with the Max Planck Institute’s Department of Microstructure Physics and Alloy Design in Germany. With its high pH and a concoction of heavy metals potentially harmful to nature and human health, the safe disposal of red mud is a costly waste management nightmare with inherent risks and technological challenges, he explains.
A disaster in Hungary in 2010 highlighted this problem when a red mud reservoir collapsed with devasting consequences, polluting nearby towns and leaving a lasting ecological legacy. A similar incident occurred in the Brazilian state of Para in 2018, where chronic toxic contamination caused traditional community residents to accuse the Brazilian government and transnational alumina refining companies in 2020 of “genocide legalized and supported by the state.”
Iron and nickel mining come with their own concerns. Nickel is in high demand in its own right, but is also critical to the stainless steel industry, with an estimated two-thirds of global nickel production used in steelmaking. Mining for nickel is responsible for water pollution and health impacts in major producer countries like Indonesia.
Iron mining also comes with a dirty legacy. In the past 10 years, Brazil endured its worst ever mining disasters, when iron ore tailing dams failed at two locations, unleashing deadly torrents of toxic red mud impacting more than 1.6 million people, despoiling the entire 850-kilometer (530-mile) length of the Doce River and ravaging communities.
Beyond these high-profile catastrophes, Luiz Jardim Wanderley, a professor of geography at Fluminense Federal University, in Rio de Janeiro state, says that mining for iron ore, bauxite and other minerals has left a toxic legacy of environmental and community harm as well as human rights and Indigenous rights abuses in the Amazon and other parts of Brazil.
Research shows that while relatively small areas of land are disturbed for iron mining, the industry has knock-on effects far beyond the mines themselves and counts as an often underrecognized driver of deforestation. A 2017 study found that mining activities caused nearly 10% of Amazon deforestation.
Environmentalists and public health experts also worry that this status quo will continue unabated as demand for bauxite and other metals grows. It’s likely new areas of the Amazon and southern Brazil will be opened up to mining to feed the world’s energy transition, says Jardim Wanderley.
Jamaica has also long borne the burden of bauxite mining, says Theresa Rodriguez-Moodie, CEO of the Jamaica Environment Trust (JEC). Her organization has monitored myriad impacts, ranging from biodiversity loss to environmental justice issues. Mining there is also linked to the release of dust and other pollutants that impact health.
“In mining communities, we interviewed about 140 individuals; 98% indicated that they have been affected by this pollution, and 64% have been affected by water pollution,” says Rodriguez-Moodie, who notes that a full health impact study has yet to be done.
JEC research, while recognizing the $1 billion economic value of the bauxite industry to Jamaica’s economy, also estimates immense health, social and environmental harm to the country and its citizens totaling “13-18 billion U.S. dollars,” Rodriguez-Moodie says.
Toward a cleaner future?
The steel and aluminum industries both see themselves as being on a pathway to improving their production practices, with respective net-zero and sustainability goals set by individual companies and international bodies.
For Pfister, the professor at ETH Zurich, the key first step is removing coal from the aluminum and steel processing supply chains — though he acknowledges this can only go so far in cleaning up these industries.
“If we’re able to turn the tide and … stop using coal power for the smelting process from alumina to aluminum, you’re cutting 80% of your emissions almost off the top,” adds Mighty Earth’s Groch. “But even though there’s lower greenhouse gas emissions from bauxite mining and alumina production, the simple fact is the environmental and health costs are a lot more grave than they are for the smelting process.”
Experts say that cleaning up these two high-demand metals will ultimately involve a whole suite of cradle-to-grave supply chain solutions.
Both sectors could be a perfect fit for the circular economy, as aluminum and steel can, under ideal circumstances, be recycled and refashioned while retaining their original state and strength. Aluminum and stainless steel already have good recycling rates. But fully achieving this global vision of sustainability comes with a hefty cost and a step change in the way these materials are viewed and used.
“We know that transition minerals will be needed at scale across all sectors of the energy transition,” says Avan from the Business & Human Rights Resource Centre. “But there has to be attention to try to reduce demand for minerals, because mining operations always have an environmental and social impact … It’s a combination of recycling, reusing, and also increasing material efficiency of end products.”
Banner image: Blast furnace in Duisburg, Germany. Research produced by the Öko-Institut for WWF found that iron and steel facilities are the biggest climate polluters of industry in Germany, followed by cement and concrete. “If you want to reduce emissions in the industrial sector, then of course, iron and steel is key,” says Öko-Institut senior researcher Hauke Hermann, who led the study. Image by Herbert Aust via Pixabay (Public domain).
Read Part Two:
Aluminum and steel vital to energy transition, but need circular solutions
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