A direct effect on human health related to climate change is the likely increase in infectious diseases transmitted by insects or through contaminated water. In the March 25th issue of The New England Journal of Medicine, infectious disease researcher Emily Shuman points out that insects are more active at higher temperatures and broaden their range. Altered, weather patterns bring drought to some areas, flooding to others and a higher likelihood of water contamination to both.
The World Health Organization predicts a 3 to 5 percent increase in the population at risk for malaria with a temperature increase of 2 to 3 degrees Celsius. And two degrees is our best-case scenario right now. The WHO also sees 10 percent more diarrheal diseases related to unclean water by 2030 due to climate change. Shuman urges the development of warning systems to spot disease outbreaks early.