Given two areas with equal sunlight and available water. area i has a high amount of atmospheric carbon dioxide while area ii has a low amount of atmospheric carbon dioxide. how does the rate of photosynthesis in area i compare to that in area ii? atmospheric carbon dioxide has no effect on the rate of photosynthesis. the rate of photosynthesis increases with a decrease in carbon dioxide. the rate of photosynthesis increases with an increase in carbon dioxide. the level of carbon dioxide increases with the level of available oxygen.