Emissions of planet-warming methane fell last year as oil and gas production declined, but they were still equivalent to the European Union’s total carbon dioxide emissions. Oil and gas operations emitted just over 70 million metric tons of methane into the atmosphere in 2020, according to the International Energy Agency’s latest edition of its annual Methane Tracker report released on Monday. Emissions were 10% lower than the estimate for 2019 amid production cuts and the introduction of new methane regulations.

“The task now for the oil and gas industry is to make sure that there is no resurgence in methane emissions, even as the world economy recovers, and that 2019 becomes their historical peak,” said IEA executive director Fatih Birol. “Early action on methane emissions will be critical for avoiding the worst effects of climate change.”

Methane emissions are the second-largest cause of global warming after carbon dioxide. While methane is less abundant in the atmosphere than carbon dioxide, and has a shorter lifetime, it absorbs much more energy than CO₂, so it’s a more powerful greenhouse gas.

Agriculture remains the largest source of human-caused methane emissions, while the energy sector comes next. Oil production is responsible for around 40% of the energy industry’s methane emissions, with the natural gas value chain accounting for the remaining 60%.

Detecting methane emissions has been a challenge in the past because they are mostly caused by hard-to-detect leaks, but over the last few months new satellites have provided a way to identify large discharges.