The US Department of Energy on April 25 released its preliminary estimate [13] for the nation's carbon emissions in the previous year. While falling far short of the kind of drop needed to meet the Paris Agreement [14] goals, a dip in emissions was recorded—almost entirely due to changes in the electric power sector. US carbon emissions have been trending downward since 2007, when they peaked at about six gigatonnes. The COVID-19 pandemic produced a dramatic drop in emissions in 2020, bringing the yearly total to below five gigatonnes for the first time since before 1990, when DoE monitoring began. Carbon dioxide releases rose after the return to "normalcy [15]"; 2023 marked the first post-pandemic decline, with emissions again below five gigatonnes.
The DOE's Energy Information Agency (EIA [17]) divides sources of carbon dioxide into five sectors: electricity generation, transportation, and residential, commercial and industrial activities. The EIA assigns 80% of the 2023 reduction in US emissions to changes in the first sector—the only one that's seen significant change in the entire 30-year period of EIA monitoring.
At the turn of the 21st century, coal accounted for over half of US electricity generation; it's now down to 16%. Within the next two years, coal is set to be surpassed by wind and solar, which were indistinguishable from zero percent of generation as recently as 2004. The most significant change, however, has been the rise of natural gas, which went from 10% of generation in 1990 to over 40% in 2023.
A small contributor to the lower emissions came from lower demand—this dropped by a percentage point compared to 2022. However, electrification of transport and appliances, along with the growth of AI processing, are expected to send demand soaring in the near future.
Currently, electricity generation accounts for 30% of US carbon emissions. That places it as the second most significant contributor, behind transportation, which is responsible for 39% of emissions. (A reversal in the situation from a decade ago [18].) The EIA rates transportation emissions as unchanged relative to 2022, despite air travel returning to pre-pandemic levels and a slight increase in gasoline consumption. Later this decade, tighter fuel efficiency rules are expected to drive a decline in transportation emissions, which are only down about 10% compared to their 2006 peak. (ArsTechnica [19])
Despite instability in the Middle East [20], and a price cap [21] and limited sanctions [22] on Russian hydrocarbons, oil prices [23] have risen only modestly through the crises in Ukraine and now Gaza. The price currenty stands at $83.57 a barrel, down from the $100 per barrel mark briefly approached [24] last year. US domestic production [25] hit an all-time high in 2023, exerting a stabilizing effect on the world market. (CNBC [26], PBS NewsHour [27])
