While previous studies have focused on greenhouse gas emissions directly associated with mineral processing, such as fuel and electricity consumption, the emissions resulting from primary mining activities like soil and vegetation removal have been largely overlooked.
The Current State of Mining in Brazil
Our research shed light on the current state of mining in the country. We revealed that over 5 million hectares of land, an area equivalent to the Netherlands' territory, are designated for mining purposes. These areas stock approximately 2.5 gigatonnes of CO2 equivalent (Gt CO2eq), mainly in the form of plant biomass (0.87 Gt CO2eq) and soil organic matter (1.68 Gt CO2eq). This significant carbon stock is at risk of being released as CO2 through the decomposition of vegetation and soil organic matter. Preserving or recovering such stock is crucial, as its release would be equivalent to around 5% of annual CO2 emissions from human activities worldwide.
Reconstructing Soil through Technosols
To address this challenge, we have explored the potential of reconstructing soil in mined areas. These artificial soils, called Technosols, can be created using various materials derived from human activities, including industrial, urban, and mining waste and residues. When Technosols possess the necessary properties, they can support the growth of agricultural plants or natural vegetation and sequester carbon through organic matter accumulation. We estimate that up to 60% of the lost soil carbon (equivalent to 1 Gt CO2eq) could be recovered through Technosol construction.
Restoring Ecosystem Services
In addition to climate regulation, Technosols offer the opportunity to restore other essential ecosystem services that are lost due to mining activities. These services include food and energy production, biodiversity protection, regulation of water quality, and nutrient cycling. Moreover, constructing Technosols using waste and residues provides a viable solution for their proper management, minimizing the risk of environmental disasters.
The Promise of Technosols
The approach to soil reconstruction relies on natural processes such as weathering, soil formation, and soil organic matter stabilization. By leveraging these processes, degraded areas can be restored, and healthy soils capable of providing ecosystem services and sequestering carbon can be created. Considering the extensive areas dedicated to mining, not only in Brazil but also in significant mining countries like China, the United States, and Australia, the construction of Technosols emerges as a promising nature-based solution (NbS) for mitigating climate change.