Climate models suggest that continued increases in methane levels could see global temperatures increase by 3-4 degrees Celsius by 2100, researchers from the Global Carbon Project said in a statement published Wednesday.
Researchers looked at methane emissions from 2000 to 2017, the last year for which complete global data are available, and warn that the current path leads toward a "dangerous temperature threshold," according to the statement.
Both natural disasters, such as wildfires, floods and droughts, and social disruptions, including mass migrations and famines, would become "almost commonplace," it said.
Methane is 28 times more effective than carbon dioxide at trapping heat over 100 years, the team said, and human activity accounts for more than half of methane emissions.
Annual emissions of the greenhouse gas have risen by 9% since 2000, which has the same effect on warming as adding 350 million cars to our roads.
The team, led by Rob Jackson, a professor of Earth system science in Stanford University's School of Earth, Energy & Environmental Sciences, published two papers in the journals Earth System Science Data and Environmental Research Letters on Wednesday.
The research showed that cattle ranching is the main reason for increased methane levels.
"Emissions from cattle and other ruminants are almost as large as those from the fossil fuel industry for methane," Jackson said. "People joke about burping cows without realizing how big the source really is."
Agriculture as a whole produces two-thirds of total emissions, with rice cultivation and biomass burning also significant contributors, according to the researchers.
Fossil fuels account for most of the remaining third, and the two sources have contributed almost equally to the recent increases.
While carbon emissions fell significantly during the coronavirus lockdown, as manufacturing and transport activity fell o