Accounting for methane from natural gas infrastructure in United States greenhouse gas emission estimates

Abstract

The Environmental Protection Agency (EPA) estimates that United States net greenhouse gas emissions have declined over the last two decades and are now about 17 % below their 2005 level. However, a large body of independent measurements suggests that over the same time frame, surging oil and natural gas production from shale formations increased emissions of methane, a potent greenhouse gas and the main component of natural gas, well beyond EPA estimates. Accounting for these increased methane emissions removes over two-thirds of the apparent post-2005 decline in United States net greenhouse gas emissions. This result suggests that Americans may need to work harder than expected to reduce emissions at a speed and scale consistent with international climate goals, highlights the need to mitigate methane emissions, and calls into question the role of natural gas in climate action plans. Other nations should carefully consider methane emissions when evaluating the climate impacts of oil and natural gas imported from the United States.