<b>Clean Technology Innovation and Rare Earth Supply: The Moderating Role of Sustainability Uncertainty</b>

We construct a composite CTI index from patent activity in electric mobility and wind-energy technologies and examine ten major REE-producing economies over 2000–2023. Clean-technology investment (CLI) is also incorporated as a complementary investment-side determinant. Given the strong cross-sectional dependence and slope heterogeneity identified in the data, we employ dynamic CS-ARDL as the main estimator and Dynamic Common Correlated Effects (DCCE) as a robustness approach.</p><p dir="ltr">The results provide three main insights.

First, clean-technology innovation is positively associated with REE mine supply in both the short and long run, indicating that technological progress in REE-intensive clean-technology sectors is accompanied by stronger upstream supply responses. Second, the interaction between CTI and SUI is negative, showing that higher sustainability uncertainty weakens the supply response associated with clean-technology innovation.

This moderating relationship is evident in the short-run CS-ARDL estimates and receives additional long-run support from the DCCE estimates. The finding helps explain why technological progress does not necessarily translate proportionately into new upstream mineral capacity when producers face greater uncertainty surrounding sustainability-related conditions. Third, clean-technology investment is positively associated with REE supply in the long run, highlighting the complementary role of investment in translating technological opportunities into productive capacity.</p>