Industrial-scale mining in Africa to support global supply chains is leading to unprecedented deforestation across the continent, with 34 hectares of forest removed for every single hectare of active mine site.

The scale of mining’s deforestation footprint is laid bare in a new University of Sheffield-led study showing that, between 2001 and 2020, 187,000 hectares of forest were lost to mining activity in Africa - an area roughly equivalent in size to the country of Mauritius.

Using satellite imagery and statistical modelling, researchers found that vast swathes of forest are being lost to make way for the infrastructure supporting mines, such as roads, housing settlements and agricultural land to feed workers.

The first large-scale study of mining-triggered deforestation across Africa, published in Nature, compared deforestation rates in mined areas to geographically similar non-mined areas.

Mines extracting cobalt and copper were found to cause the highest rates of overall deforestation. These metals are critical components in renewable energy technologies, electric vehicles and household electronics. Mining for high value minerals such as gold and silver, and critical manufacturing minerals such as iron, also drove higher rates of deforestation.

Co-lead author Dr Oscar Morton, from the University of Sheffield’s School of Biosciences, said: “The actual mines themselves are just the tip of the iceberg. It’s the extent of additional deforestation triggered by mining that is far greater, with new settlements, agriculture and transport routes posing a serious threat to vital forests across the continent.

“As demand for minerals continues to rapidly grow, it’s crucial that robust measures are put in place to limit the extra deforestation caused by mining and its supply chains.”

Researchers studied over 16,000 mines, from large-scale mines operated by multinational corporations to ‘artisanal’ mines, often operated by individuals, families or local cooperatives.

The scale of mining operations across Africa is a direct result of increased global demand, with the extraction of metal ores quadrupling in the continent since 1970. As the global appetite for key minerals underpinning the transition to green energy technologies continues to grow, demand is expected to increase 40 fold by 2040.

“As consumers of products that rely heavily on minerals mined in Africa, such as mobile phones, electric vehicles and solar panels, we are a part of a global supply chain that’s driving unprecedented deforestation across the continent,” said co-lead author Dr Chris Bousfield from the University of Sheffield’s School of Biosciences.

“Whilst these minerals are essential for fueling the green energy transition, it’s vital that this does not come at the expense of the continent's already severely diminished forest habitats. Like we’re beginning to see in the food and drink industries, we need to embed zero deforestation or no-net-loss supply chains across the mining industry.”

Professor David Edwards in the Department of Plant Sciences at the University of Cambridge, senior author of the study, said: "Metals including cobalt and copper are critical components of technology from electric vehicles to smart phones and computers. But our study shows there are unintended consequences of the appetite for technology. We find that cobalt and copper mining drives particularly high levels of offsite deforestation, particularly in the hyper-biodiverse rainforests of the Democratic Republic of the Congo."

Africa holds the largest deposits of minerals vital to the green energy transition in the world, but its mining industry suffers from poor regulation and governance, lacks transparency and is linked to severe human rights violations.

Environmental impact assessments for new mines tend to consider only the immediate site, failing to factor in the footprint of associated infrastructure, which can stretch kilometers beyond the mine itself.

Prince Dégny Valé, a contributor to the study from the Côte d’Ivoire’s Université Jean Lorougnon Guédé, has a keen interest in the impacts of gold mining across the country.

He said: “With nearly 30% of the world’s mineral resources, the rapid expansion of the mining sector in Africa is generating significant economic opportunities for both governments and local populations. However, this growing interest in mining is placing increasing pressure on natural ecosystems and local communities.

“In Sub-Saharan Africa, many developing countries sometimes face limited law enforcement capacity. Mining activities, in addition to causing habitat fragmentation and soil and water pollution, are at the center of numerous social conflicts related to access to resources. This raises the challenge of reconciling economic development with biodiversity conservation.”

While the study focussed on Africa because of its rich deposits of key minerals that are integral to green technologies, researchers say it must be scaled up to a global level to build a holistic picture of the true environmental impact of mineral extraction.Dr Victor Maus, from the Institute for Ecological Economics, WU Vienna University ofEconomics and Business, has spent years building a database detailing mining activity across the world.

He said: “This analysis covers Africa, but based on the data we’ve collected, it is likely that similar impacts are replicated elsewhere. The indirect footprints of mines extend way beyond their physical limits. Our data also shows that mining is particularly concentrated in areas with rich biodiversity, such as tropical forests.

“While the commodities mined will change by country, the overall impact on deforestation is likely to be the same. To create realistic life cycle analyses of mining, data at country or commodity level isn’t enough. We need to understand the geographical location mine by mine – and for that, satellite data will only provide half the picture.

“We also need companies to be more transparent with their environmental as well as ownership and financial data. Only then will we have the information we need to fully understand – and where necessary mitigate – the real environmental impact of extracting these key minerals.”

Read the study in full