Carbon dioxide emissions in the United States plunged 10% in 2020 as stay-at-home orders and the economic slump driven by the Covid-19 pandemic took a toll on energy demand.

According to a new report by the International Energy Agency, annual carbon dioxide (CO2) emissions fell by almost 500 million metric tons in 2020, accelerating a trend of declines that had already been in motion for years.

“With a strong coal-to-gas shift as natural gas prices have moved toward historic lows, and the rapid growth of renewables, emissions from coal-fired power generation declined 27% from 2015 to 2019,” according to researchers.

CO2 emissions hit their lowest point in the spring as states implemented stay-at-home orders, but started to bounce back as the restrictions were lifted. By...