As climate change intensifies, high-emission firms exhibit lower price valuation ratios compared to their low-emission counterparts within the same country. Using data from 43 major equity markets, we find that high-emission firms respond to equity price pressure by reducing carbon emissions, increasing green innovation, and downsizing operations. These changes are unlikely consequences of broader economy-wide trends, as similar patterns are not observed among private high-emission firms. To address endogeneity concerns, we employ an instrumental variable approach using local natural disasters as exogenous shocks to high-emission firms’ stock prices, yielding consistent results. Our findings contribute to the ongoing debate on the effectiveness of sustainable investing by demonstrating its tangible impact on firm behavior.