Carbon dioxide emissions lead to the increase of the planet's temperature, contributing to the greenhouse effect. That is so because it causes damage in the ozone layer, a barrier from the sun rays. Once there is a damage, through it the sun has a deeper contact with humans causing diseases. Once the temperature raises, all the cycles suffer with its influence (water cycle of evaporation, rain, etc), The CO2 concentration in the air causes pollution and respiratory diseases and affect the plants photosyntesys and so on.