Methane is less abundant in the atmosphere
than carbon dioxide, but it is more potent in its near-term effects on global
warming. Large amounts of methane pour into the air from wells and pipelines,
sometimes through unintentional leaks. Other sources include livestock,
landfills and the decay of organic matter in wetlands. Atmospheric concentrations of methane have
increased steadily over the past 15 or so years, and in 2021, they rose by a
record amount over the year before, reaching a new high, according to
preliminary analysis by the National Oceanic and Atmospheric Administration.
The previous record for annual increase in methane levels had been set in 2020. “Our data show that global emissions
continue to move in the wrong direction at a rapid pace,” said Richard W.
Spinrad, the NOAA administrator. “Reducing methane emissions is an important
tool we can use right now to lessen the impacts of climate change in the near
term, and rapidly reduce the rate of warming.” Surging methane emissions in recent years
have brought increasing attention to the gas’ role in accelerating climate
change. Carbon dioxide still contributes much more
to the warming of the planet overall. The NOAA analysis published Thursday
indicates that levels of carbon dioxide also continued to rise rapidly in 2021.
During the past 10 years, carbon dioxide concentrations grew at their quickest
pace in the six-plus decades since monitoring began, NOAA said. However, because of how much more methane
contributes to warming over shorter periods of time, scientists regard reducing
methane emissions as a way to curb warming more rapidly. And, unlike carbon dioxide, which is
released into the atmosphere when fossil fuels are burned for energy, methane
is the main component of natural gas, which means emitters have economic
reasons not to let too much of it be released into the air through leaks. The
energy industry accounts for about one-third of global methane emissions,
scientists estimate. Apart from trapping heat at Earth’s
surface, methane also contributes to ground-level ozone pollution, which can
cause breathing problems and other health issues. By NOAA’s estimates, methane
is now more than 2 1/2 times more abundant in the atmosphere than it was before
the Industrial Revolution. At a global climate summit last year in
Glasgow, Scotland, more than 100 nations joined together and pledged to slash
global methane emissions 30 % by 2030. The Biden administration has announced
new rules governing methane from oil and gas rigs across the United States. One factor that may have contributed to the
rapid growth in methane emissions during the past two years might be increased
rainfall in tropical regions resulting from the climate phenomenon known as La
Niña, said Xin Lan, an atmospheric scientist at the NOAA Global Monitoring
Laboratory in Boulder, Colorado. The added rain and moisture may have led to
increased methane production by microbes living in tropical wetlands, she said.
These micro-organisms are also more active in warmer weather, she said, so
natural emissions from wetlands and other places may be generally increasing as
the planet heats up. Even so, limiting leaks from fossil fuel
facilities should be an easier way to stabilise methane levels than trying to
manipulate rainfall in the tropics, Lan said. “Fossil-fuel methane emission
reduction seems to be low-hanging fruit to us,” she said, particularly given
that emitters could be using this methane as fuel and making money from it. That leaked methane is “a waste of pure
energy,” Lan said. “It shouldn’t be there in the atmosphere.” 
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