Burning fossil fuels (coal, natural gas and oil) for energy purposes releases a gas called carbon dioxide (C02)into the atmosphere. The ever-increasing levels of Co2 in the atmosphere contribute to global warming and thus harm the environment. In order to combat global warming, scientists have proposed capturing CO2 from industrial facilities that use fossil fuels and storing it underground. The captured Co2 would be transported to storage sites and injected into deep underground rocks. However, there are several significant challenges that make it difficult to store CO2 underground. Storage First, there is the question of whether locations proposed for storing Co2 have enough space. The burning of fossil fuels around the world releases billions of tons of Co2 into the atmosphere annually. In order to make a considerable difference in combating global warming, most of the released Co2 would need to be captured and stored underground. It is not clear whether underground sites suitable for CO2 storage have enough space. Health Risks Second, if C02 escapes from underground storage sites, it can pose risks to human health. CO2 leaks may occur if, for example, unforeseen natural processes or forces create cracks in the ground above the storage site. Although the normal atmospheric levels of Co2 are harmless, high concentrations of Co2 may be unsafe, causing headaches, tiredness. and possibly even death. High Costs Finally, a wide range of costs are associated with the process of storing CO2 underground. First, new technologies for capturing and storing C02 that currently do not exist will have to be created. In addition, new infrastructure, such as pipelines transporting Co2 from industrial facilities to storage sites. will have to be built. All of these requirements will likely result in very high costs for constructing and operating CO2 storage systems.