Mining causes direct and indirect loss of tropical forests
Stefan Giljum, Victor Maus, Nikolas Kuschnig, Sebastian Luckeneder, Michael Tost, Laura J. Sonter & Anthony J. Bebbington
FINEPRINT Brief No. 17, March 2023
The growing demand for minerals continues to drive deforestation worldwide. Tropical forests are particularly vulnerable to the environmental impacts of mining and mineral processing. In this study, we present the first biome-wide assessment to show where industrial mine expansion has caused the most deforestation over the past two decades. We find that 3,264 km² of forest was directly lost due to industrial mining, with 80% occurring in only four countries: Indonesia, Brazil, Ghana, and Suriname. Additionally, controlling for other non-mining determinants of deforestation, such as agriculture, we find that mining caused indirect forest loss in two-thirds of the investigated countries. Our results call for impact assessments and mitigation plans of industrial mining to address both direct and indirect impacts in order to support conservation of the world’s tropical forests.
This FINEPRINT Brief builds on the paper ‘A pantropical assessment of deforestation caused by industrial mining’ published by Giljum and colleagues in PNAS. The datasets used for the analysis are available for download from PANGAEA.
Driven by rising affluence and surging demand for minerals for consumer products, infrastructure, and energy transition technologies, global mining activities expanded at an unprecedented pace in the past 20 years . Today, mines worldwide extract double the amount of raw materials compared to the year 2000, with the trend expected to continue in the coming decades . Resource-extracting regions face extensive land-use changes due to the expansion of mining activities and related infrastructure, often accompanied by deforestation .
Compared to other causes of tropical deforestation, such as crop production or livestock farming, mining is so far often considered a minor driver. However, its growing importance has been emphasised in various case studies and our work suggests that the overall deforestation caused by mining is underestimated, as indirect effects are often not considered. In our study, we provide an investigation of deforestation impacts induced by industrial mining operations across 26 countries located in tropical wet and dry forests. To quantify deforestation we intersect mining polygons of an earlier study  with areas of tropical forest loss over the period from 2000 to 2019 using the Global Forest Change dataset .
Our assessment framework considers both direct and indirect deforestation impacts of industrial mining. Direct deforestation occurs within the mining area itself through establishing or expanding extraction sites, tailing storage facilities, waste rock dumps, and on-site processing facilities and roads. In addition to quantifying direct deforestation within mining areas, we set up a statistical model to assess whether mining induces indirect deforestation in its surroundings. Indirect deforestation occurs outside areas designated for mining and emerges through various pathways. For example, mineral extraction and processing require large amounts of energy, demanding infrastructure for energy generation. Building up infrastructure for mineral processing, storage, and transport is another pathway leading to indirect deforestation. Expansion of mining sites may also lead to in-migration and growth of settlements in the surrounding areas, creating new agricultural land and pastureland with impacts on forest loss.
Direct deforestation within mining areas
The investigated mining areas covered 11,467 km² of land that included 7,019 km² of tropical forest in 2000. By 2019, 3,264 km² (46.5%) of these forest areas were directly lost to industrial mine expansion. With 1,901 km² of deforested area, Indonesia was by far the most affected country, accounting for almost 60% of direct forest loss by mining across all 26 investigated countries (Figure 1). Mine expansion in East Kalimantan on the island of Borneo for coal production was the main factor behind this development in Indonesia. Deforestation within Brazil’s mining areas located in tropical forest biomes extended over 327 km² since 2000. Ghana (213 km²), Suriname (203 km²), and Côte d’Ivoire (99 km²) follow as the countries with the highest direct forest loss. All other countries together made up 16% of tropical forest loss by mining observed across the 26 countries.
While for most countries the direct deforestation effects of mining (on-site) are rather small compared to other land-intensive activities, such as the production of soybeans and palm oil or cattle farming, some countries show considerably higher shares in total forest loss, e.g. Suriname with 11% and Guyana with 4%.
Indirect deforestation induced by mining
We find strong evidence that mining also induces indirect deforestation outside areas designated for mining activities. In 18 of the 26 investigated countries, deforestation rates are higher close to the actual mining areas than areas farther away than 50 km, even when controlling for other known determinants of tropical deforestation, such as proximity to agriculture or roads. These indirect impacts are estimated using the distance to the closest mine in a spatial statistical model. Thus, if deforestation increases with higher proximity to the mines, we expect this to indicate indirect deforestation effects of the corresponding mines.
In Brazil and Indonesia, we find high statistical significance for higher deforestation 50 km around the actual mining sites. On average, and holding all other parameters fixed, reducing the distance to a mine in Brazil by 10% (e.g. from 10 to 9 km) leads to a 3% increase in deforestation. For Indonesia, this value is 2.3%. The absolute effects of these results can be illustrated with a scenario simulation: For instance, if all mines in Indonesia were to expand their borders by 100 m, this would induce an additional deforestation between 194 and 215 km². In Brazil, the same 100-m expansion would lead to 147 to 154 km² of additional forest loss. Apart from Indonesia and Brazil, the statistical relation of mines causing indirect deforestation can also be observed for many other tropical countries, including Guyana, Colombia, the Philippines, Papua New Guinea and the Democratic Republic of the Congo (DRC).
Figure 2 provides a visualisation of the statistical results. Map (a) shows the coefficients for mining-induced deforestation in all 26 investigated mining countries with tropical forests. A negative coefficient indicates that mining drives off-site deforestation. The impacts of industrial mining on forest loss can also be illustrated on a spatially explicit level by considering the distance of each grid cell to the nearest mine (b). These three maps for mining regions in Brazil, the DRC, and Indonesia thus illustrate the importance of mining-induced deforestation in total forest loss in each grid cell. White areas indicate that no forest loss has been observed since 2000. The importance of forest loss due to industrial mining is clearly visible in the state of Minas Gerais in Brazil, where iron ore and gold are particularly mined in the “Iron Quadrangle” in the south. The indirect deforestation induced by mining in the Central African Copperbelt, stretching between Zambia and the DRC, is illustrated in the second example. As a third case, we show the Indonesian mining regions on the island of Borneo, where coal, nickel, and tin mining significantly expanded since the year 2000.