According a Paris-based data analytics company, Kayrros SAS, the 12th highest methane emission rate detected this have been recorded in Bangladesh.
"It has the strongest sustained emissions we have seen to date where we can't clearly identify the source," said Stephane Germain, president of GHGSat Inc, which also picked up the plumes, reports Bloomberg.
Bluefield Technologies Inc., which analysed European Space Agency data to identify a large methane plume in Florida in May, also detected the concentrations over Bangladesh.
"Our analysis shows that Bangladesh has some of the highest methane emissions in the world that can be detected by satellites," said Yotam Ariel, the company's founder.
Recently scientists have begun to pinpoint the biggest sources of methane. Observations from space can be seasonal due to cloud cover, precipitation and varying light intensity. Satellites can also have difficulty tracking offshore emissions and releases in higher latitudes such as the Arctic, where Russia has extensive oil and gas operations. Existing data isn't yet globally comprehensive because of these limitations.
Bangladesh's low elevation and high population density makes it particularly vulnerable to extreme weather events and rising oceans. The country chairs the Climate Vulnerable Forum, whose 48 members represent 1.2 billion people most threatened by climate change.
"We are aware of the problems," Bangladesh's Environment and Climate Change Minister Shahab Uddin said in an interview, adding that the bulk of the methane likely came from rice paddies. When farmers flood their fields, bacteria in the waterlogged soil can produce large quantities of the gas.
"The other source is the landfill gas," Uddin said, released when trash breaks down.
"We are working to take mitigation measures."
Domesticated livestock, leaks from the oil and gas industry, landfills and coal mining are just some of the human activities that result in methane emissions, according to the Global Methane Initiative. The Environmental Defense Fund estimated that at least a quarter of recent global warming is caused by man-made methane emissions.
Methane concentrations in Bangladesh likely originate from a combination of sources including paddy fields, landfills, leaky natural gas pipelines and coal stockpiles, according to Kayrros. The company used data from the ESA's Sentinel-5P and Sentinel-2 satellites. It ran a dispersion simulation that took into account atmospheric conditions such as wind, which can move methane plumes away from their source.
Methane is a particular concern for those working to slow the pace of climate change. The gas is odorless and colorless, making leaks extremely difficult to detect. Halting accidental emissions from energy infrastructure is some of the lowest-hanging fruit because companies stand to benefit from cleaning up operations. They are losing product that could have been sold and risk reputational damage as investors such as BlackRock Inc. demand higher standards.
"The methane concentrations we see over Bangladesh are a signal and deserve more study," said Steven Hamburg, chief scientist at the EDF, which plans to launch its own satellite to track methane emissions next year.
"It will require more work to make reliable quantitative estimates of emissions and determine sources."