Climate change is harming human health, and the magnitude of the harm is increasing. This is especially true in tropical and subtropical regions that are vulnerable to greater intensity, frequency, and duration of extreme weather, such as hurricanes, drought, and increases in heat, as a result of climate change. Nearly all countries situated in the geographic tropics are poor, and therefore have fewer resources to adapt to impacts of climate change. Protecting the public’s health in these regions from serious—potentially catastrophic—harm associated with climate change requires coordinated response from tropical medicine and global health professionals, and from leaders of civil society more broadly.