Climate change risks for copper mine closure in the Americas: regional analysis using geospatial and quantitative methods

Abstract

Climate change is creating new challenges for mine closure, especially in copper-producing regions where shifting precipitation, prolonged droughts, and extreme weather events threaten long-term stability. These risks are particularly acute in arid and semi-arid regions like the Southwestern United States and Western South America, where copper mining is concentrated and water scarcity already complicates post-mining reclamation. This study evaluated climate-driven closure risks across seven major copper regions using CMIP6 climate projections and Köppen-Geiger classifications. Scenarios under low (SSP126), intermediate (SSP245), and high (SSP585) emissions pathways were analyzed for two future periods: 2041–2070 and 2071–2099, compared against a historical baseline (1991–2020). Six climate indices were calculated to quantify risk: the Standardized Precipitation-Evapotranspiration Index (SPEI), Aridity Index (AI), Drought Frequency (DRFE), Drying Period Duration (DPD), Annual Maximum 1-day Precipitation (RX1day), and Rainfall Erosivity (R-Factor). Geospatial analysis identified regions with shifts in climate classification, highlighting areas vulnerable to drying trends, precipitation extremes, and transitional instability. Results show widespread aridification in the Arizona Copper Belt, Great Basin Copper Region, and Northern Chilean Copper Belt, particularly under SSP585. Declining AI and increased drought frequency signal heightened water stress, posing risks to pit lake hydrology, revegetation, and acid rock drainage. In contrast, the Southern Chilean and Central Peruvian Copper Belts exhibit increasing precipitation intensity, raising concerns over flooding, tailings stability, and erosion. The Northwestern Argentina Copper Belt shows high climate variability, complicating closure planning due to unstable wet-dry patterns. These findings underscore the need for climate-adaptive closure strategies. Future mine closure planning should incorporate hydrological modeling, slope stability assessments, and regulatory frameworks that account for long-term climate risks. As global copper demand rises, proactive adaptation in mining practices, water management, and reclamation will be essential to ensure environmentally responsible and resilient closures.