58 Announced Pledges Scenario (APS), incorporating announced national climate commitments; and the Net Zero Emissions Scenario (NZE), consistent with a global pathway to net-zero emissions by mid-century. For each scenario, global copper demand is reported at five-year intervals between 2025 and 2050. Annual demand trajectories over the period 2024–2050 are obtained through linear interpolation. Copper production is assumed to track demand at the global scale. Porphyry deposit data is derived from the USGS global porphyry copper database (Magnin et al. 2025), which includes 852 deposits representing approximately 2326 Mt of contained copper. To derive regional production requirements, two simplifying assumptions are applied. First, porphyry deposits are assumed to account for 82% of total copper production, consistent with their share of global copper resources. Second, South America is assumed to contribute 46% of global copper production, reflecting its current share of global production and resources. Applying these assumptions yields scenario-specific time series of required porphyry copper production in South America for the period 2025–2050. These production trajectories form the basis for estimating water demand in Section 3.2 and for evaluating water stress outcomes in Section 3.3. The analysis focuses on this single region, mineral, and time horizon to provide a transparent proof of concept rather than a comprehensive global assessment. 3.2 Porphyry Copper Water Demand under Production Scheduling For the STEPS scenario, South American porphyry copper production is scheduled at the deposit level by prioritizing higher-grade deposits and excluding deposits with less than 10 years of mine life. New deposits are activated as existing operations are exhausted to maintain annual production. Annual water requirements are calculated for the scheduled production using the parametric, process-based model described in Section 2.3. Net water requirements modelled span 35 to 4,000 m³ per tonne of copper produced, with an average of 260 m³ t⁻¹. This range reflects differences in deposit characteristics, including ore grade, deposit size, and local climate conditions.
RkJQdWJsaXNoZXIy MTM0Mzk2