With global temperatures changing faster than anyone predicted, and altering the regions where animals, viruses, and humans can live, the threat of emerging zoonotic diseases—those that began in animal populations and jump to humans—is expanding. As climatologists strive to model new weather patterns, epidemiologists are realizing how critical it is to incorporate these data if they are to anticipate the next outbreak. Journalist Lois Parshley explores a new, multidisciplinary approach that may be the key to understanding how infectious diseases arise and spread.