A gradual increase in the temperature of the atomosphere and the oceans, observed since the late 19th century and thought to be due to the so-called greenhouse effect (reduction in radiation of heat from the Earth by an increase in CO2 concentration of the atomsphere). Possible public health effects of global warming include shifts in the habitats of pathogenic organisms and vectors, food crop failures, and health hazards associated with changes of climate (elevated average regional temperatures, drought, flooding).
