By Gloria Dickie
BAKU (Reuters) – Research shows the world’s warming tropical wetlands are releasing more methane than ever before – an alarming sign that the world’s climate goals are moving further out of reach.
A massive increase in methane in wetlands – which is not accounted for in national emissions plans and undercounted in scientific models – could increase pressure on governments to make deeper cuts to their fossil fuel and agricultural industries, according to researchers.
Wetlands contain enormous amounts of carbon in the form of dead plant material that is slowly broken down by soil microbes. Rising temperatures are like stepping on the gas pedal of that process, accelerating the biological interactions that produce methane. Meanwhile, heavy rainfall causes flooding, causing wetlands to expand.
Scientists have long predicted that methane emissions in wetlands would rise as the climate warmed, but from 2020 to 2022, air samples showed the highest methane concentrations in the atmosphere since reliable measurements began in the 1980s.
Four studies published in recent months say tropical wetlands are the most likely culprit for the spike, with tropical areas contributing more than 7 million tons to the methane spike in recent years.
“Methane concentrations are not only rising, they are rising faster over the past five years than ever before in the data,” said environmental scientist Rob Jackson of Stanford University, chairman of the group that publishes the five-year Global Methane Budget, last published in September .
Satellite instruments revealed that the tropics were the source of a large increase. Scientists further analyzed various chemical signatures in the methane to determine whether it came from fossil fuels or a natural source – in this case wetlands.
Congo, Southeast Asia and the Amazon (NASDAQ:) and southern Brazil contributed the most to the tropical peak, researchers found.
Data published in Nature Climate Change in March 2023 shows that annual emissions from wetlands over the past two decades were about 500,000 tonnes per year higher than what scientists had predicted under the worst climate scenarios.
Capturing emissions from wetlands is a challenge with current technologies.
“We should probably be a little more concerned than we already are,” says climate scientist Drew Shindell of Duke University.
The La Nina climate pattern, which brings heavier rainfall to parts of the tropics, appeared to be somewhat responsible for the surge, according to a study published in September in the journal Proceedings of the National Academy of Sciences.
But La Nina alone, which last ended in 2023, can’t explain the record high emissions, Shindell said.
For countries trying to tackle climate change, “this has major implications when planning for the reduction of methane and carbon dioxide emissions,” said Zhen Qu, an atmospheric chemist at North Carolina State University who led the study on the impacts of La Nina led.
If methane emissions in wetlands continue to rise, scientists say governments will need to take stronger action to keep warming at 1.5 C (2.7 F), as agreed in the United Nations Paris climate agreement.
WATER WORLD
Methane is 80 times more powerful than carbon dioxide (CO2) at trapping heat over 20 years, and is responsible for about a third of the 1.3 degrees Celsius (2.3 F) of warming the world has experienced since 1850 registered. However, unlike CO2, methane washes out of the atmosphere after about ten years, making it less impactful in the long term.
More than 150 countries have pledged to make a 30% reduction from 2020 levels by 2030 to tackle leaking oil and gas infrastructure.
But scientists have yet to see a slowdown, even as technologies to detect methane leaks have improved. According to the International Energy Agency’s 2024 Global Methane Tracker report, methane emissions from fossil fuels have remained at a record high of 120 million tonnes since 2019.
According to a U.N. Environment Program report published Friday, satellites have also picked up more than a thousand large plumes of methane from oil and gas activities over the past two years, but notified countries responded to only 12 leaks.
Some countries have announced ambitious plans to reduce methane.
China said last year it would aim to curb flaring, or burning, emissions from oil and gas wells.
President Joe Biden’s administration last week finalized a methane tax on major oil and gas producers, but it is likely to be scrapped by the incoming presidency of Donald Trump.
Democratic Republic of Congo’s Environment Minister Eve Bazaiba told Reuters on the sidelines of the UN climate summit COP29 that the country was assessing methane rises from the Congo Basin’s swampy forests and wetlands. In the 2024 methane budget report, Congo was the largest hotspot of methane emissions in the tropics.
‘We don’t know how much [methane is coming off our wetlands]she said. “That’s why we’re bringing in those who can invest in this way, also to do the monitoring to take stock of how much we have, how we can also exploit them.”
