Tropical deforestation significantly increases local temperatures by reducing the cooling effect of trees through shade and evapotranspiration. This warming exposes over 300 million people across Central and South America, Africa, and Southeast Asia to higher heat levels, contributing to an estimated 28,000 heat-related deaths annually in the tropics. Heat stress from this warming exacerbates health risks and reduces productivity, revealing a hidden public health crisis alongside the well-known climate impacts of carbon emissions. New tools and initiatives aim to provide localized data and financial incentives to support forest conservation and mitigate these health hazards.