Not even months of quarantine orders that confined millions of Americans to their homes were enough to unseat transportation as the leading source of greenhouse gas emissions in the United States — and cars are the biggest polluters in the sector, a new study finds.
According to preliminary estimates from the Rhodium Group, transportation-related emissions were still the United States’ single biggest driver of climate change in 2020, despite historic drops in vehicle miles travelled and a relatively large drop in tailpipe smog compared to prior years.
Planes, trains and automobiles (and presumably to a lesser extent, boats) accounted for an estimated 31 percent of total net emissions in 2020, and the transportation industry experienced the largest drop in total emissions of any sector — though not enough to dethrone it as the nation’s top polluter. And if the Rhodium estimates hold, the industry’s slice of the climate change pie will actually be larger than it’s been in years past; it was just 28 percent in 2018, the most-recent year for which the Environmental Protection Agency has provided final data.
And a closer look at the data reveals that not all modes contributed equally to the transportation sector’s historic emission declines — because decreases in driving were considerably lower than decreases in flying.
Demand for jet fuel fell to as low as 32 percent of 2019 levels at the height of the COVID-19 lockdowns, and barely achieved 65 percent of those levels even when travel demand rose in around the December holidays. Gasoline demand, by contrast, had already rebounded to about 90 percent of its pre-pandemic levels by the last month of the year, and diesel demand was roughly the same as it was  in December 2019 — a surge which the Rhodium analyst says was “likely spurred by holiday deliveries.”
National vehicle miles travelled, meanwhile, were only down about 15 percent in 2020 compared to the 2019 annual total — and that’s even accounting for a historically unprecedented 40-percent VMT drop-off in April, when more states and cities had implemented shelter-in-place orders than at any other point in the pandemic.
The Rhodium analysts say our national patchwork of quarantine mandates probably explain most of the transportation sector’s emissions seeming “wins.” (Before you ask: no, this was far from banner year for fuel emissions standards, electric vehicle adoption, or even the sale of plain-old fuel-efficient vehicles.) But some advocates are wondering why 2020’s driving-related emissions weren’t even lower — and if a global pandemic couldn’t do it, it what it might take to finally get Americans out of their cars at large scale.

True.