The world’s largest oil and gas companies pledged in 2018 to reduce the proportion of methane released from their operations by one fifth, to less than a quarter of a percentage of the gas they sell, by 2025 — a target the companies said they reached last year — with an ambition of achieving 0.2 percent.
Minimizing methane from landfills also plays a role, as does lowering methane emissions from livestock. But emissions-reduction technologies are less certain in those fields. Releases from livestock, in particular, are expected to make up a growing share of future methane emissions unless there are technological breakthroughs, or the world’s top meat consumers change their diets.
Over all, more than half of global methane emissions stem from human activities in three sectors: fossil fuels, landfill and other waste, and livestock and other agriculture. Methane also seeps from wetlands and other natural sources.
The U.N. report also underscores how reducing methane emissions may bring significant public health benefits. Methane is an important contributor to the formation of ozone near the earth’s surface. Ozone is known to increase the risk of hospitalizations and early deaths. It also reduces crop yields and forest growth.
Rolling back methane emissions would prevent more than 250,000 premature deaths, and more than 750,000 asthma-related hospital visits, each year from 2030 onward, the report finds. The lower emissions would also prevent more than 70 billion hours of lost labor from extreme heat and more than 25 million tons of crop losses a year.
The flip side is that, with no action, methane emissions may help push the world to the brink of catastrophic climate change. If left unchecked, methane emissions are projected to continue rising through at least 2040, the U.N. report predicts.
“We’re still going wildly in the wrong direction, but we can turn that around very, very quickly,” Dr. Shindell said. “We could all use a climate success story.”