Global warming is a great concern throughout the world. The ill effects of global warming like change in climate, temperature, rainfall, humidity, level of carbon di-oxide has been found to have both positive and negative effects on insects, which in turn reduces the effectiveness of crop protection measures. This creates the need for global warming to be taken as an important criterion in Entomology. Being poikilothermic in nature insects are greatly affected by changing temperature. Insect will experience additional life cycles with rapid growth rate. As a result of changes in the population dynamics including distribution and migration the reliability on current insect pest ETL will be reduced. Increased insect pests outbreak will affect agricultural production. Research on basic biology of insect, population dynamics and behaviour patterns should be focused to ascertain the effect of global warming on insect behaviour.