Growing nickel supply from the tropics threatens priority conservation areas.

Increasing global demand for nickel, an essential metal in low-carbon technologies and stainless steel, is driving a surge in mining in strongholds of tropical biodiversity. We use a global mine-by-mine supply scenario model to quantify the trade-off between meeting future nickel demand for decarbonization and conserving areas critical for achieving biodiversity and climate targets. Nickel laterites-near-surface deposits often found beneath tropical forests-account for 78 to 83% of modelled supply between 2025 and 2050. Over this timeframe, half of mined nickel threatens the top 10% of global land areas most critical for conserving biodiversity and storing carbon, but avoiding mining in these areas increases the risk of supply shortfalls. In addition, 53 to 60% of future supply comes from coastal mines, which threaten the top 10% of global priority areas for conserving marine biodiversity. While deep-sea resource development remains controversial, we show that a moratorium may increase reliance on nickel sourced from high-priority areas for conserving terrestrial and coastal marine biodiversity. Securing ecologically responsible nickel supply requires integrating terrestrial and marine conservation priorities to inform sourcing and mine development decisions, alongside efforts to mitigate unavoidable impacts, increase resource exploration and reduce long-term demand.