Globally, the reduction of greenhouse gas emissions, particularly of carbon dioxide (CO2), has become increasingly important. Currently, much of the carbon dioxide emitted to the atmosphere is from the burning of fossil fuels in the transportation and energy (electricity and heating) sectors. Significant emission reductions may be achieved in the energy sector through fuel switching to less carbon-intensive fuels, energy efficiency, and in the transportation sector by improving efficiency through the use of intermodal shipping and through the use of alternative fuels such as biofuel. Additionally, research and development in geologic sequestration methods that can be used to store CO2 is ongoing. This can be accomplished by underground injection for enhanced oil recovery (EOR) or injection into deep saline aquifers.