Dictionary.net

• an increase in the average temperature of the earth's atmosphere (especially a sustained increase that causes climatic changes)

2006 - WordNet 3.0
By Princeton University

• The effect of global warming and the resulting increase in world temperatures. The predicted health effects of such long-term climatic change include increased incidence of respiratory, water-borne, and vector-borne diseases.

2010 - Medical Dictionary Database
By DataStellar Co., Ltd