Climate-Action Driven Emission Changes of Unintentional Persistent Organic Pollutants From Global Copper Industry.

Climate action is shifting copper production from primary copper smelting (PCU) toward secondary copper smelting (SCU_RF), an important source of unintentional persistent organic pollutants (UPOPs). However, climate-driven changes in UPOP emissions across the copper industry remain poorly understood. Here, emissions of six Stockholm Convention-listed UPOPs from global and regional copper-smelting subsectors during 2023-2050 are estimated under different climate scenarios. Toxic equivalent (TEQ)-based emissions are used to compare relative toxic potency, while mass emissions are also quantified to reflect non-TEQ-based management relevance. By 2050, global UPOP emissions under a net-zero pathway are projected to be 10%-31% higher than under the current-policy pathway. The TEQ emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs), together with mass emissions of hexachlorobenzene (HCB) and pentachlorobenzene (PeCBz), warrant attention. SCU_RF is projected to contribute 62%-98% of total TEQ emissions across UPOPs, making it the priority control source, while mass emissions of HCB and PeCBz from PCU and direct melting of high-quality scrap should receive attention. Climate-action-driven TEQ emission increases are concentrated in East Asia and the Pacific and in Europe and Central Asia. These findings reveal a pollution trade-off in copper decarbonization and highlight the need for targeted control strategies.