Climate change in terms of increase in atmospheric carbon dioxide and temperature has impact on agriculture including insect pests that minimize the crop yields. To address these impacts, biological studies on aphid, Aphis gossypii Glover on Bt cotton was conducted for six generations during 2013-14 and 2014-15 under different climate change conditions. The results revealed that the biometry of aphid was influenced by increased carbon dioxide (550 ppm CO2 ) and temperature (rise in 2°C of the prevailing temperature). This was evidenced by decrease in nymphal developmental time (3.67 ± 0.21 days), longevity of adult (9.43 ± 0.41 days), increased fecundity (32.46 ± 0.95) and reduced life cycle (12.28 ± 0.23 days) in the elevated conditions (both 550 ppm CO2 with 32°C as well as in 550 ppm CO2 + 34°C). However, morphometry of aphid showed slight variations in all the treatments but, aphids under elevated conditions showed reduced body size which indicated that the fitness of aphid was effected in the enriched carbon dioxide (CO2 ) and temperature conditions.