Gas flaring at an oil rig. Pic courtesy Ken Doerr. Flickr / CC BY 2.20
Hannah Stewart
Mainstream attention is all focused on rising carbon dioxide, a clear cause of global warming. But less attention has been focused on methane, which is responsible for a quarter of the warming seen today.
A new analysis points out that reducing methane emissions may give humans a little more room to maneuver, cutting down about a quarter degree Celsius (0.45 degrees Fahrenheit) of warming by 2050.
Climate change mitigation is the idea that reducing or preventing greenhouse gas emission now can soften the blow of climate change later. Most conversations about mitigation focus on carbon dioxide, the most common greenhouse gas, which made up 80% of U.S. emissions in 2019.
Methane, though, has 28-36 times the Global Warming Potential of carbon dioxide, and traps more heat. It also produces ozone at the ground level, which is toxic to plants.
But it also has a much shorter lifespan in the atmosphere. While carbon dioxide may linger in the atmosphere for centuries, methane only lasts for about 12 years, during which it combines with oxygen to form more carbon dioxide and hydrogen. Methane may play a smaller role in the long-term, but cutting down emissions can provide some immediate relief from climate change now.
Ilissa Ocko, a senior scientist at the Environmental Defense Fund, speaks up for methane mitigation in her recent paper.
“Acting rapidly to deploy readily available methane mitigation measures by sector can immediately slow global warming.” she says.
Ocko’s research focuses on how different human activities contribute to climate change. According to her, “One of the complexities with that is that each different type of pollutant we emit impacts the climate in a different way.”
For the last decade, the EDF has been studying methane emissions from the oil and gas industry. The new study expanded that focus to calculate the impacts of methane emissions from all sources, including livestock, rice agriculture, landfills, and coal mining.
The study surveyed existing economically and technologically feasible methane mitigation methods. It and came up with three theoretical possible simulations involving implementing them at different speeds: “fast action,” in which mitigation measures are deployed by 2030; “slow action,” which begins in 2020 but will not be fully deployed until 2050; and “delayed action,” in which mitigation initiatives begin in 2040 and are complete by 2050.
The study found that starting all mitigation measures immediately can slow short-term global warming by 30%. This would avoid the 0.25 degrees Celsius of warming we mentioned by the middle of the century.
The researchers rejected more radical possibilities, such as phasing out methane pipelines or even a global vegan revolution. They used a popular analysis software often used when making policy decisions known as the Model for the Assessment of Greenhouse-gas Induced Climate Change. Yes, MAGICC.
Ocko had previously tested MAGICC, which relies on repetitive computer simulations, to ensure its reliability. Still, this study was dealing with a moving target and the simulations had to be repeatedly reworked to incorporate the new data.
A slightly exasperated Ocko commented, “New research is always coming out and so…the number of times I reran my model simulations because better data existed [was high].”
Around the time that Ocko was frequently recalculating her model’s new data, she also became a first-time mother – a time of bleary-eyed days and sleepless nights that are hard enough without the stress of, well, having to try and save the world. In addition, the dearth of childcare available during to COVID-19 hampered her work, even though she was working remotely.
The biggest problem was intellectual ennui, or, as Ocko put it, “trying to get the novelty of it out there. I think a lot of times it was interpreted as, ‘but we know all of this.’” She says that this was particularly true of the time they sent the paper out for peer review.
The researchers ran 50 separate 335-year simulations, for the years 1765 to 2100. They found that if no changes are made, methane emissions will rise by 70% by 2100. A third of this will come from livestock, oil and gas, and landfills. Methane contributes 0.5 degrees Celsius (0.9 degrees Fahrenheit) to global warming – which is half of what carbon dioxide does. It does not bode well for us if a lot more methane breaks down into carbon dioxide.
If not addressed, methane emissions could contribute to around 0.9 degrees Celsius (1.6 degrees Fahrenheit) by 2100. Quick action to cut methane emissions could slow warming between 2030 and 2050 by 12%. Methane mitigation is now as productive if efforts are slowly ramped up until 2050, which would mean a 5% increase in the average rate of global warming.
That would not bode well for our immediate future.
Hannah Stewart is an editorial assistant for a cancer research publishing house by day and a freelance science writer by night. She specializes in the environmental sciences with a focus on climate change.
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