Many human activities are responsible for the production of greenhouse gases. Generating electricity is the single largest source of CO2 emissions in the United States, followed by transportation. Negative externalities are created by individuals that engage in more than the economically efficient amount of an activity, such as driving. Because the driver enjoys all of the benefits that come along with driving and only suffer part of the cost, they do not put a limit on how far or how often they should drive. The only way to get individuals to participate in reducing greenhouse gases is by having them bear all the costs of their actions. This is difficult because the costs are so little compared to the benefit, so why give up something that benefits more than sets you back. Two different methods are being proposed to help humans take into consideration the costs of their actions to reduce the production of greenhouse gases. The methods proposed are government regulation and taxation. Unless the government sets regulations and taxes, the individual level of involvement will be very low and unless many people participate, the number of greenhouse gases will not be significantly reduced. Carbon dioxide (CO2) makes up the vast majority of greenhouse gas emissions from the sector, but smaller amounts of methane (CH4) and nitrous oxide (N2O) are also emitted. These gases are released during the combustion of fossil fuels, such as coal, oil, and natural gas, to produce electricity.