https://www.independent.co.uk/environment/methane-paris-climate-change-crisis-atmosphere-noaa-a8928711.html
[images and links in online article]
Methane being released faster than ever, posing new threat to Paris
climate goals
Risings emissions from tropical regions possibly due to climate feedback
loop
Phoebe Weston
Science Correspondent
May 23, 2019
Record levels of methane in the atmosphere will make it even harder to
reach targets set by the Paris climate agreement, scientists have warned.
Researchers from the National Oceanic and Atmospheric Administration
(NOAA) found increasing amounts of the potent greenhouse gas were coming
from the tropics.
They are uncertain about the source but believe it is likely to be due
to microbial changes in methane-belching tropical wetlands. They believe
warmer temperatures could be causing them to emit more methane than ever
before.
“Methane’s unexpected rise is a major challenge to the Paris agreement
and we don’t know why it’s happening,” Euan Nisbet, professor of earth
sciences at Royal Holloway University of London, told the Financial Times.
“It looks very much as if the warming is feeding the warming, but
exactly how is a major puzzle,” he said.
Methane is the second largest cause of human-induced global warming
after carbon dioxide. It is 28 times more potent and can trap heat in
the atmosphere for more than 100 years.
Researchers found the amount of methane released increased by 50 per
cent between 2013 and 2018 compared with the five years before.
Professor Grant Allen, an atmospheric physicist from the University of
Manchester who has been working on the Global Methane Budget project,
told the The Independent this increase will “without a doubt” make it
harder to reach the Paris emissions goal.
“Since 2006 methane concentrations in the atmosphere have been rising
and not only rising but accelerating. All of the atmospheric models that
try and explain where those extra emissions come from have been pointing
us towards the tropics. We never had measurements there until recently,”
he said.
“We’ve been doing campaigns in the tropics and we went out with an
aircraft in January and February. Sure enough we did see huge amounts of
methane being emitted from stagnant freshwater swamps, especially in
Zambia.”
The hypothesis is that as the climate warms the efficiency of the
microbial communities that convert organic matter into methane increases.
Like our bodies, bacteria are most efficient at warmer temperatures so
as the climate warms these emissions are likely to increase.
“This is really a worry because this is a natural feedback and something
we can’t control. It’s likely to begin with these feedbacks will be slow
but they will rapidly become something we can’t control. Our scope to
mitigate impacts is going,” said Prof Allen.
“If we were to stop all natural gas use tomorrow we could reverse this.
It’s only increasing because it’s the sum total of all these effects –
our anthropogenic emissions and our natural emissions. If the climate
continues warming this natural feedback could certainly accelerate.”
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