Why are carbon dioxide concentrations expected to increase? A) Carbon dioxide concentrations are expected to increase, because fossil fuel burning is expected to increase. B) Carbon dioxide concentrations are expected to increase, because of an increase in agriculture. C) Carbon dioxide concentrations are expected to increase, because more land will have to be cleared for increasing populations and agricultural use. D) Carbon dioxide concentrations are expected to increase, because the amount of vegatation cover and hence photosynthesis which reduces it continue to decrease. E) All of the above