Climate change is the term used to describe a gradual increase in the average temperature of the Earth’s atmosphere and its oceans, a change that is believed to be changing the Earth’s climate forever. Insects are cold-blooded organisms - the temperature of their bodies is approximately the same as that of the environment. Therefore, temperature is probably the single most important environmental factor influencing insect behaviour, distribution, development, survival, and reproduction. Anthropogenic CO2 is almost twice more important for temperature increase than other long-lived greenhouse gases combined. Although increased CO2 should not directly deleteriously affect insects, the temperature increases driven by the increase in anthropogenic CO2 already affect insects in profound ways including their distribution, nutrition, phenology and role as disease vectors.