Some discrepancy is found between different sources. This increase in water temperature does have an adverse affect on the aquatic life in those systems. Neighboring ground water can also have negative effects. Different types of systems utilize and modify ground water in different ways. Like geothermal energy's effects on the surrounding water, it can also alter the air around it.
Carbon dioxide is prevented from entering the Earth's atmosphere before exiting the system.
This is then re-injected back into geothermal formation, therefore, recycling the energy. This leaves a minute or zero emission of carbon dioxide into the environment. Of more concern to environmentalists is the emission of hydrogen sulfide into the atmosphere, which can lead to the production of acid rain. These gasses produce an unpleasant odor when the system is not operated properly. This gaseous release can be toxic to humans at high concentrations and produce a rotten egg odor at low concentrations.