We could be 16 years into a methane-fueled 'termination' event significant enough to end an ice age

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Planet Earth

Climate Change

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Sascha Pare

published 16 August 2023

Methane emissions from tropical wetlands have been soaring since 2006 and accelerating at the same breakneck speed as when Earth's climate has flipped from a glacial to an interglacial period.

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Methane is a powerful greenhouse gas emitted from both natural and human-caused sources.

(Image credit: Reuben Krabbe/ Ascent Xmedia via Getty Images)

A dramatic spike in atmospheric methane over the past 16 years may be a sign that Earth's climate could flip within decades, scientists have warned.

Large amounts of methane wafting from tropical wetlands into Earth's atmosphere could trigger warming similar to the "termination" events that ended ice ages — replacing frosty expanses of tundra with tropical savanna, a new study finds. Researchers first detected a strange peak in methane emissions in 2006, but until now, it was unclear where the gas was leaking from and if it constituted a novel trend.

"A termination is a major reorganization of the Earth's climate system," study lead author Euan Nisbet , a professor emeritus of Earth sciences at Royal Holloway, University of London, told Live Science. "These repeated changes have taken the world from ice ages into the sort of interglacial we have now."

Ice age terminations typically occur in three phases, which are recorded in ice cores going back 800,000 years . The initial phase is characterized by a gradual rise in methane and CO2, leading to global warming over a few thousand years. This is followed by a sharp increase in temperatures fueled by a burst of methane, leveling off in a third phase lasting several thousand years.

Related: New map of methane 'super-emitters' shows some of the largest methane clouds ever seen

"Within the termination, which takes thousands of years, there's this abrupt phase, which only takes a few decades," Nisbet said. "During that abrupt phase, the methane soars up and it's probably driven by tropical wetlands."

Methane is a powerful greenhouse gas released both by human activities — including fossil-fuel burning, landfills and agriculture — and natural processes, such as decomposition in wetlands. Human emissions soared in the 1980s with the expansion of the natural gas industry and stabilized in the 1990s, Nisbet said.

Plants that grow in tropical wetlands decompose and release methane into the atmosphere.

(Image credit: Humberto Ramirez via Getty Images)

But in late 2006, something "very, very odd" happened, he said. Methane started rising again, but there was no dramatic shift in human activity to blame — and researchers were left scratching their heads. Then, in 2013, Nisbet and his colleagues realized this rise was accelerating . By 2020, methane was increasing at the fastest rate on record, he said.

"It looks as if there's a big, new methane source turning on," Nisbet said.

A flurry of studies since 2019 has linked the strange spike to soaring emissions from tropical wetlands, predominantly in Africa. A "significant change" in tropical weather ascribed to human-caused climate change has led wetlands to get bigger and more plants to grow there, thus leading to more decomposition — a process that produces methane, Nisbet said.

In the new study, published July 14 in the journal Global Biogeochemical Cycles , Nisbet and colleagues compared current trends in atmospheric methane to the abrupt phase of warming during ice age terminations.

"The closest analogy we have to what we think is happening today is these terminations," Nisbet said.

— Massive methane leaks mapped from space

— First underwater methane leak discovered near Antarctica

— Huge methane cache beneath Arctic could be unlocked by the moon

While the evidence remains inconclusive, the scale of such a shift in climate is worth pondering, he added. In the past, terminations have flipped vast expanses of icy tundra in the Northern Hemisphere into tropical grasslands roamed by hippos, Nisbet said. There is no way to know what a termination could signify today, given that we are not in an ice age. "We're not saying we've got proof this is happening, but we're raising the question."

Regardless of whether termination-scale climate shifts are on the horizon, tackling methane emissions should be high on our list of priorities, Nisbet said. "We can do a great deal to bring down methane," he said, and this includes plugging gas leaks, and tackling emissions from manure, landfill and crop waste.

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Sascha Pare

Sascha is a U.K.-based trainee staff writer at Live Science. She holds a bachelor’s degree in biology from the University of Southampton in England and a master’s degree in science communication from Imperial College London. Her work has appeared in The Guardian and the health website Zoe. Besides writing, she enjoys playing tennis, bread-making and browsing second-hand shops for hidden gems.

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3 Comments

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Broadlands "Regardless of whether termination-scale climate shifts are on the horizon, tackling methane emissions should be high on our list of priorities, Nisbet said. "We can do a great deal to bring down methane," he said, and this includes plugging gas leaks, and tackling emissions from manure, landfill and crop waste." However, none of that can be effectively done without using conventional transportation. And that adds CO2 in the process. Between a rock and a hard place? Reply

rjh The authors mistakenly state we are not in an ice age. We are in an ice age that started 3 million years ago, in an inter-glacial where the ice partially and temporarily receded 10,000 years ago. Would breaking out of an ice age be bad, overall? Things would change. "At least five major ice ages have occurred throughout Earth's history: the earliest was over 2 billion years ago, and the most recent one began approximately 3 million years ago and continues today ( yes, we live in an ice age !). Currently, we are in a warm interglacial that began about 11,000 years ago." Reply

Giovani admin said: Methane emissions from tropical wetlands have been soaring since 2006 and accelerating at the same breakneck speed as when Earth's climate has flipped from a glacial to an interglacial period. We could be 16 years into a methane-fueled 'termination' event significant enough to end an ice age : Read more admin said: Methane emissions from tropical wetlands have been soaring since 2006 and accelerating at the same breakneck speed as when Earth's climate has flipped from a glacial to an interglacial period. We could be 16 years into a methane-fueled 'termination' event significant enough to end an ice age : Read more So many aspects to the current climate models. Ironically, humankind may be staving off the return to a cyclic ice episode naturally occurring but overridden due to the introduction of carbon emissions. If we were able to reduce this human generated condition, the earth would rapidly cool as should be. Ironic would be the word to describe our mortal wisdom. Reply

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Planet Earth. Climate Change. News. Sascha Pare. published 16 August 2023. Methane emissions from tropical wetlands have been soaring since 2006 and accelerating at the same breakneck speed as when Earth's climate has flipped from a glacial to an interglacial period. Comments (3) Methane is a powerful greenhouse gas emitted from both natural and human-caused sources. (Image credit: Reuben Krabbe/ Ascent Xmedia via Getty Images) A dramatic spike in atmospheric methane over the past 16 years may be a sign that Earth's climate could flip within decades, scientists have warned. Large amounts of methane wafting from tropical wetlands into Earth's atmosphere could trigger warming similar to the "termination" events that ended ice ages — replacing frosty expanses of tundra with tropical savanna, a new study finds. Researchers first detected a strange peak in methane emissions in 2006, but until now, it was unclear where the gas was leaking from and if it constituted a novel trend. "A termination is a major reorganization of the Earth's climate system," study lead author Euan Nisbet , a professor emeritus of Earth sciences at Royal Holloway, University of London, told Live Science. "These repeated changes have taken the world from ice ages into the sort of interglacial we have now." Ice age terminations typically occur in three phases, which are recorded in ice cores going back 800,000 years . The initial phase is characterized by a gradual rise in methane and CO2, leading to global warming over a few thousand years. This is followed by a sharp increase in temperatures fueled by a burst of methane, leveling off in a third phase lasting several thousand years. Related: New map of methane 'super-emitters' shows some of the largest methane clouds ever seen. "Within the termination, which takes thousands of years, there's this abrupt phase, which only takes a few decades," Nisbet said. "During that abrupt phase, the methane soars up and it's probably driven by tropical wetlands." Methane is a powerful greenhouse gas released both by human activities — including fossil-fuel burning, landfills and agriculture — and natural processes, such as decomposition in wetlands. Human emissions soared in the 1980s with the expansion of the natural gas industry and stabilized in the 1990s, Nisbet said. Plants that grow in tropical wetlands decompose and release methane into the atmosphere. (Image credit: Humberto Ramirez via Getty Images) But in late 2006, something "very, very odd" happened, he said. Methane started rising again, but there was no dramatic shift in human activity to blame — and researchers were left scratching their heads. Then, in 2013, Nisbet and his colleagues realized this rise was accelerating . By 2020, methane was increasing at the fastest rate on record, he said. "It looks as if there's a big, new methane source turning on," Nisbet said. A flurry of studies since 2019 has linked the strange spike to soaring emissions from tropical wetlands, predominantly in Africa. A "significant change" in tropical weather ascribed to human-caused climate change has led wetlands to get bigger and more plants to grow there, thus leading to more decomposition — a process that produces methane, Nisbet said. In the new study, published July 14 in the journal Global Biogeochemical Cycles , Nisbet and colleagues compared current trends in atmospheric methane to the abrupt phase of warming during ice age terminations. "The closest analogy we have to what we think is happening today is these terminations," Nisbet said. — Massive methane leaks mapped from space. — First underwater methane leak discovered near Antarctica. — Huge methane cache beneath Arctic could be unlocked by the moon. While the evidence remains inconclusive, the scale of such a shift in climate is worth pondering, he added. In the past, terminations have flipped vast expanses of icy tundra in the Northern Hemisphere into tropical grasslands roamed by hippos, Nisbet said. There is no way to know what a termination could signify today, given that we are not in an ice age. "We're not saying we've got proof this is happening, but we're raising the question." Regardless of whether termination-scale climate shifts are on the horizon, tackling methane emissions should be high on our list of priorities, Nisbet said. "We can do a great deal to bring down methane," he said, and this includes plugging gas leaks, and tackling emissions from manure, landfill and crop waste. Live Science newsletter. Stay up to date on the latest science news by signing up for our Essentials newsletter. Terms & Conditions. Privacy Policy. Sascha Pare. Sascha is a U.K.-based trainee staff writer at Live Science. She holds a bachelor’s degree in biology from the University of Southampton in England and a master’s degree in science communication from Imperial College London. Her work has appeared in The Guardian and the health website Zoe. Besides writing, she enjoys playing tennis, bread-making and browsing second-hand shops for hidden gems. 'The stage was now set for the birth and growth of desert dunes': How the Sahara turned from a vast forest to the arid landscape we see today. 15 unexpected effects of climate change. Bizarre polygons on Mars' surface hint that alien life on Red Planet was possible. See more latest  ►. See all comments (3) 3 Comments. Comment from the forums. Broadlands "Regardless of whether termination-scale climate shifts are on the horizon, tackling methane emissions should be high on our list of priorities, Nisbet said. "We can do a great deal to bring down methane," he said, and this includes plugging gas leaks, and tackling emissions from manure, landfill and crop waste." However, none of that can be effectively done without using conventional transportation. And that adds CO2 in the process. Between a rock and a hard place? Reply. rjh The authors mistakenly state we are not in an ice age. We are in an ice age that started 3 million years ago, in an inter-glacial where the ice partially and temporarily receded 10,000 years ago. Would breaking out of an ice age be bad, overall? Things would change. "At least five major ice ages have occurred throughout Earth's history: the earliest was over 2 billion years ago, and the most recent one began approximately 3 million years ago and continues today ( yes, we live in an ice age !). Currently, we are in a warm interglacial that began about 11,000 years ago." Reply. Giovani admin said: Methane emissions from tropical wetlands have been soaring since 2006 and accelerating at the same breakneck speed as when Earth's climate has flipped from a glacial to an interglacial period. We could be 16 years into a methane-fueled 'termination' event significant enough to end an ice age : Read more admin said: Methane emissions from tropical wetlands have been soaring since 2006 and accelerating at the same breakneck speed as when Earth's climate has flipped from a glacial to an interglacial period. We could be 16 years into a methane-fueled 'termination' event significant enough to end an ice age : Read more So many aspects to the current climate models. Ironically, humankind may be staving off the return to a cyclic ice episode naturally occurring but overridden due to the introduction of carbon emissions. If we were able to reduce this human generated condition, the earth would rapidly cool as should be. Ironic would be the word to describe our mortal wisdom. Reply. View All 3 Comments. Most Popular. Mystery mass death of seals on remote, uninhabited Siberian island under investigation. By Jacklin Kwan August 16, 2023. By Sascha Pare August 16, 2023. No, this spider's venom will not give you a permanent erection, but it might last a few hours. By Ben Turner August 16, 2023. Europe's 1st humans were likely wiped out by a sudden freeze 1.1 million years ago. By Tom Metcalfe August 15, 2023. Maui satellite photo shows full scale of deadliest US fire for more than a century. By Harry Baker August 15, 2023. Drones equipped with lasers uncover secrets of bloody WWII battle. By Kiley Price August 15, 2023. Odds of 'strong' El Nino now over 95%, with ocean temperatures to 'substantially exceed' last big warming event. By Sascha Pare August 15, 2023. Medieval girl buried face down with bound ankles, likely so she couldn't 'return' from the grave. By Laura Geggel August 15, 2023. Vlad the Impaler may have cried tears of blood, chemical analysis of his letters finds. By Jennifer Nalewicki August 15, 2023. Save $85 on the Soundcore Liberty 3 Pro Earbuds at Amazon. By Ravi Davda August 15, 2023. Save 56% with this Garmin Enduro smartwatch deal. Hurry, before it sells out! By Ravi Davda August 15, 2023. 1 What's the largest planet in the universe? 2 100-year-long 'megastorms' on Saturn are creating radio signals that scientists can't fully explain. 3 Medieval girl buried face down with bound ankles, likely so she couldn't 'return' from the grave. 4 2,000-year-old gold treasure from Iron Age tribe unearthed by metal detectorists in Wales. 5 Mystery mass death of seals on remote, uninhabited Siberian island under investigation. 1 We could be 16 years into a methane-fueled 'termination' event significant enough to end an ice age. 2 Vlad the Impaler may have cried tears of blood, chemical analysis of his letters finds. 3 Medieval girl buried face down with bound ankles, likely so she couldn't 'return' from the grave. 4 Europe's 1st humans were likely wiped out by a sudden freeze 1.1 million years ago. 5 Drones equipped with lasers uncover secrets of bloody WWII battle.