Fossil fuels are normally stored in a reservoir deep in the earth. the carbon in fossil fuels including coal and oil are essentially locked out of the natural carbon cycle due to their location deep in the earth. humans have found a way to access and utilize this carbon. identify a risk for accessing this carbon

The world has become very dependent on carbon-rich fossil fuels over time because of its high calorific value. This means that it produces a big amount of energy when it undergoes combustion. However, the by-product of combustion of carbon is carbon dioxide. It is a known greenhouse gas and pollutant. This is the risk the scientists fear that might affect the environment in the long run.

So, the answer is: Scientists are not sure if the atmosphere can handle all of the excess carbon.