As commuters stayed home in 2020 and airplanes remained on the ground, the nationwide slowdown led to a sizable drop in heat-trapping emissions. U.S. greenhouse gas emissions fell by 10 percent, the largest annual drop since World War II, according to a report by the Rhodium Group.
Still, the climate diet isn't likely to stick. The reductions were largely due to temporary changes during lockdown orders. By the end of the year, Americans were already back to driving and flying more.
To make the deep cuts that climate scientists say are needed to avoid the worst impacts of climate change, the U.S. will need to make more lasting changes, like switching the nation's electric grid to solar, wind and other low-carbon energy sources.
"The emission reductions of 2020 have come with an enormous toll of significant economic damage and human suffering," says the report by the Rhodium Group, an independent research firm. "Without meaningful structural changes in the carbon intensity of the US economy, emissions will likely rise again as well."
The dip in 2020 also isn't likely to dramatically slow the rate of climate change. While emissions over the last year were less than expected, the U.S. continued polluting, so the overall amount of carbon dioxide in the atmosphere went up. Essentially, it's like a bathtub being filled with water. The U.S. turned down the faucet, but it was still filling the tub.
Transportation, the largest source of U.S. emissions, fell by almost 15 percent in 2020 compared to the previous year. Demand for jet fuel fell almost 70 percent in April and has only rebounded by about half since, according to the report. Diesel fuel, which powers the trucking industry, stayed fairly constant as goods and deliveries continued to flow.
Still, not all of the reductions are fleeting. While the demand for electricity was close to normal in 2020, emissions from power plants fell by 10 percent, due in large part to the continued decline of coal. Once the dominant source of electricity in the country, coal-fired power plants have been shuttering in recent years, driven out of business by the low cost of natural gas and renewable energy.
The emissions drop in 2020 is also a sobering reminder of how far the U.S. has to go to achieve international climate targets. Even with the pandemic-driven drop, the country still didn't reach the emissions cuts it had pledged under the Paris Agreement, which aimed for greenhouse gas pollution at 26 to 28 percent below 2005 levels.
The Biden Administration has vowed to make climate a priority, including rejoining the international agreement. But with the Trump Administration's reversal of many Obama-era climate policies, Biden will have to take on even more ambitious policies.