Greenhouse gas emissions in the United States dropped by an estimated 10.3% over the course of 2020 compared to the previous year, according to an analysis by the research firm Rhodium Group.
The decline was driven by COVID-19-related economic disruptions. Emissions from various sectors including transportation, energy generation, industry, and buildings all declined as local and state governments imposed lockdown measures to contain the virus and historic job losses dampened the overall economy.
In fact, 2020 witnessed the steepest plunge in year-on-year emissions since the World War II era, surpassing the emissions decline of the US recession in 2009.
US emissions are now 21% below 2005 levels, meaning the US technically achieved its target under the 2020 Copenhagen Accord, according to the report.
However, the authors warn that the historic news must be taken with a grain of salt.
“The vast majority of 2020’s emission reductions were due to decreased economic activity and not from any structural changes that would deliver lasting reductions in the carbon intensity of our economy,” the report said.
The authors note that emissions would have declined by only 3% if the pandemic had not occurred, driven almost entirely by the phasing out of coal as a means of energy production.
The transportation sector, for instance, saw a decline of 14.7% in emissions largely because people stopped traveling. Once the COVID-19 vaccine inoculates enough of the US public, transportation will likely increase to previous levels.
Similarly, the buildings sector had been consuming an increasing amount of energy prior to the pandemic. If and when the pandemic subsides, buildings emissions will likely rise again.
What this means is that government policy needs to capitalize on the environmental gains made over the past year, otherwise emissions will bounce back to unsustainable levels.
Achieving the Paris climate agreement requires countries to rapidly zero out their annual emissions over the next several years, reaching net zero emissions sometime over the next two decades. The only way this can happen is if emissions continue to decline at around the same pace as 2020.
The report warns that emissions in 2021 will likely increase because of returning economic activity.
The incoming administration of President-elect Joe Biden can help the US make some of the structural changes needed to lock in long-term emissions reductions, including by, for example, reinstating the energy regulations repealed by the current administration, rejoining the Paris climate agreement, ending subsidies for fossil fuels, and investing in energy efficiency measures for transportation and buildings.