A worldwide inventory of methane sources reported by researchers online in Environmental Research Letters reveals that atmospheric levels of the heat-trapping greenhouse gas are at an all-time high.

Africa and Asia are seen as major contributors due to increasing agriculture activity. Increasing fossil fuel use and landfill waste also heighten emissions in China and the United States.

Science News reports that methane “is one of the most important greenhouse gases—arguably the second-most important after CO2,” according to atmospheric scientist Alexander Turner. Methane can trap approximately 30 times as much heat as the same amount of CO2. Possible solutions include strategies to moderate pollution such as consuming less meat to cut down on emissions from cattle ranches and using aircraft or satellites to find gas pipeline leaks. In 2017, human activities discharged about 364 million metric tons of methane into the atmosphere, compared with 324 million tons per year on average in the early 2000s. About half of the increase was the result of expanding agriculture and landfills, while the rest came from fossil fuels. Emissions from natural sources such as wetlands held steady.