Unequal impacts of rising temperatures on global human sentiment

Climate change poses growing risks to human well-being, yet research on its emotional impact has primarily focused on developed nations, obscuring potential global inequalities in psychological vulnerability. Here, we analyze over 1.2 billion social media posts from 157 countries to reveal how rising temperatures affect human sentiment worldwide and project future impacts under climate scenarios. We find a non-linear relationship where moderate warming can improve sentiment in cooler regions, but temperatures above 35°C negatively impact emotional well-being globally, with effects three times greater in low- and middle-income countries (25.0% decline in sentiment) than in high-income countries (8.1%). Even accounting for climate adaptation through income growth, we project global average sentiment will be 2.3% lower in 2100 than in 2019 due to future warming, indicating lasting psychological costs disproportionately burdening the world's poorest populations. These findings underscore the urgent need for climate policies that integrate emotional impacts and address inequalities in psychological climate vulnerability.