The United States uses approximately 5% of its primary energy and 6% of its electricity to pump, convey, treat, distribute, heat, and recondition water in the US public water supply. Allocating this energy towards water has contributed to a national public water distribution system that is considered among the best in the world, providing its users with a clean and reliable water supply. This water supply, treated to stringent water standards defined by the Environmental Protection Agency’s Safe Drinking Water Act, has been critical to the health and livelihood of United States’ citizens. However, this energy-expenditure comes at an environmental cost, since the majority of water-related energy is derived from burning fossil fuels. Fossil-fuel combustion emits carbon-dioxide, a greenhouse gas that has become of concern in recent years because of its connection to anthropogenic climate change. The amount of carbon-dioxide that is emitted from fossil-fuel combustion is principally a function of the quantity and type of fuel that is burned for energy. This first-order analysis quantifying national water-related carbon dioxide emissions is the second in a series of several analyses by the authors, quantifying the energy and greenhouse emissions embedded in the US public water supply. Results indicate that water withdrawal, conveyance, treatment, distribution, end-use preparation, and wastewater treatment produces approximately 301 million metric tonnes of CO2 emissions annually. This quantity is 5.1% of total US CO2 emissions in 2009, which is approximately equal to emissions from the gasoline consumed by one-quarter of the US passenger fleet in the same year. Considering that the emissions associated with water for industrial, municipal and self-supplied sectors (such as agriculture) were not included in this analysis, the actual quantity of carbon emissions released as a result of water-related activities is likely to be higher. Consequently, identifying efficiency measures and conservation schemes to reduce the amount of water-related energy consumed in the US might be significant in achieving future greenhouse gas emission reduction goals.
Global trends in carbon dioxide (CO2) emissions from fuel combustion in marine fisheries from 1950 to 2016
