Methane: Even Worse Than CO2
WHY YOU SHOULD CARE
The faster Arctic ice melts, the more buried methane will be released and the more swiftly we’ll hurtle toward a warming planet.
By Melissa Pandika
Carbon dioxide is usually judged public enemy number one when it comes to greenhouse gas emissions. But new research suggests we may be overlooking a more dangerous villain: methane.
True, CO2 accounted for roughly 64 percent of the world’s greenhouse gas emissions from human activities in 2007, while methane made up just 14 percent. CO2 also remains in the Earth’s atmosphere for up to 200 years before chemical processes break it down, compared to methane, which lasts about 12 years.
But methane packs a bigger punch: One pound traps about 25 times more heat than a pound of carbon dioxide. Even more worrisome, scientists reported last week that U.S. methane emissions might be vastly higher than EPA estimates. Another group at the University of Alaska Fairbanks concluded they had underestimated methane emissions from the Arctic seabed. If the Arctic continues to melt, huge amounts of methane could vent into the atmosphere with devastating environmental and economic consequences.
Tons of methane the U.S. released in 2008
Where does methane originate? Bacteria that live in landfills, cow intestines and many other places release methane when they make energy. It’s also the main component of natural gas. The EPA estimated that the U.S. released 32 million tons of methane in 2008. But climate scientists from Harvard University and other institutions found that the U.S. had actually released 50 percent more methane than originally estimated, according to a study published in the Proceedings of the National Academy of Sciences.
The discrepancy came mainly from the region that includes Kansas, Texas and Oklahoma, where releases from oil and gas production may be five times higher than EPA estimates. Meanwhile, cattle and other livestock throughout the country excreted about twice as much methane as previously thought.
In the ocean, methane exists as an ice-like solid called methane hydrate. More than one trillion tons of methane hydrate are thought to be buried in Arctic marine sediments and permafrost. But the Arctic is thawing fast — with some scientists predicting that the region could be completely free of summer ice as early as 2020, which could cause the methane to bubble to the surface.
Kansas, Texas, Oklahoma
Main sources for methane emissions that were overlooked in original estimates, released from oil and gas production
Percentage change in the amount of methane released into the atmosphere by the U.S. from what was originally estimated
How much more methane cattle and other livestock emit than previously thought
Last Sunday, University of Alaska Fairbanks researchers reported in Nature Geoscience that the East Siberian Arctic Shelf spews about one million tons of methane into the atmosphere each year — more than twice the amount they had estimated earlier.
The methane beneath the East Siberian Arctic Shelf “is likely to be emitted as the seabed warms, either steadily over 50 years or suddenly,” triggering a catastrophic “methane time bomb,” according to a recent Nature commentary. A sudden burst of 50 billion metric tons of methane between 2015 and 2025 would mean that the global mean temperature would rise more than 3.6 degrees Farenheit some fifteen years earlier than expected, in 2035 instead of 2050. That 3.6-degree change has been set as the threshold for potentially catastrophic climate changes, along with a cost of about $60 trillion — the equivalent of the entire world economy in 2012.
We don’t want this methane to burst or even slowly be released — we don’t want it to be released at all.
Skeptics agree that the Arctic could vent 50 billion metric tons of methane; but over centuries, not decades. Still, even a slower release would contribute to global warming, and with the unprecedented warming of the Arctic, we should be prepared for surprises.
“We don’t want this methane to burst or even slowly be released — we don’t want it to be released at all,” climate scientist Gail Whiteman of Erasmus University Rotterdam, co-author of the Arctic Shelf study, told Reuters. “But if [the world] keeps warming, it will be released. It’s just a matter of time.”
The recent findings prompted calls for tighter control of methane emissions, which are minimally regulated. In a promising first step, the European Parliament voted in favor of a measure in October that requires all shale gas firms to undertake an Environmental Impact Assessment prior to drilling. And last month, Colorado proposed air quality regulations that, if passed, would make it the first state to control methane emissions associated with oil and gas drilling.
Artic Ice and Methane’s Effects
1 trillion tons
Ice-like methane hydrate trapped in Arctic ice
Years until the Arctic will no longer be covered by summer ice, thus releasing methane to the surface
1 million tons
Methane released annually from the shallow waters of the East Siberian Arctic Shelf – twice as much as previously estimated
The debate on whether to exploit oil and gas reserves in the Arctic may also be swayed by the findings. As Whiteman says, “The Arctic is so important for the global climate system. As soon as it starts to change, we can start anticipating large impacts around the world.”
With such vast quantities of methane poised to enter the atmosphere, we need to break the cycle now, before the damage becomes irreversible.
- Melissa Pandika Contact Melissa Pandika