Human-caused methane emissions — the majority of which stem from food and
agriculture
waste,
cow
burps,
and oil and gas
operations
— are responsible for half of the planet’s warming and are likely to cause
temperatures to overshoot Paris targets in the coming decades. Recent UN
research flags the importance of
mitigating this greenhouse gas for stabilizing climate in the short term while
potentially adding another, much-needed .5°C of wiggle room for warming from
CO2.
“Decades ago, had we gotten a handle on CO2, our additional methane emissions
might not have mattered,” Erika
Reinhardt, co-founder of Spark
Climate Solutions, told Sustainable
Brands®.
But those days are gone. Continuously rising CO2 levels have pushed methane
emissions above a threshold where the short-term warming they’ll cause could
have dangerous impacts; there’s about two-and-a-half times
more
methane in the atmosphere now than before the Industrial Revolution.
Levels of the extra-potent greenhouse gas have thrown a wrench in the plans of
climate scientists, as they’re seeing greater climate impacts from methane even
at temperatures lower than predicted — “and that’s partially because the CO2
bathtub is so high now that there’s increased importance on the [methane] layer
that’s on top,” Reinhardt said. “The really important point here is that cutting
methane over the next few decades is really our only way of bringing
temperatures down.”
the exciting potential of cultivated, fermented and plant-based protein innovation
Join us as Aleph Farms, the Better Meat Co, the Good Food Institute and Plantible Foods discuss the latest advancements in cultivated, plant-based, and fermentation-derived proteins — and how incorporating alternative proteins can help brands significantly reduce environmental impacts, while conserving natural resources — Tuesday, Oct. 15 at SB'24 San Diego.
According to the IPCC’s Sixth Assessment
Report,
human greenhouse gas emissions have caused the world to warm about 1.1° C.
Methane — though with orders of magnitude less atmospheric concentration than
CO2 — is responsible for half a degree of that warming. While it only hangs
around in the atmosphere for 10-12 years, methane has about 30 times more
warming force than CO2. Nonetheless, as long as anthropogenic methane emissions
remain steady or increase, methane will continue to spend its short lifespan in
the atmosphere making the planet hotter.
“CO2 is long lived — as you emit more CO2, the atmospheric impact continues to
rise,” Reinhardt explained. “Methane is a bit different — the amount of warming
in the atmosphere is more driven by the current rate of emissions of recent
periods, rather than the accumulated emissions of decades or centuries.”
Think of it like a bathtub: As long as CO2 is turned on, the bathtub will
continue to fill up — but most of the near-term warming will come from methane.
“We have a unique opportunity by mitigating emissions to actually see some of
that warming go down, which is critically important to having manageable
temperatures over the next century,” Reinhardt said.
One of the largest anthropogenic sources of methane, oil and gas infrastructure
is particularly ripe for interventions that can be scaled now. Similarly, other
heavy-emitting sectors have their own portfolio of mitigation strategies that
should be enacted. But there’s still more to do if we want to fully
“de-methanize.” And it needs to happen fast.
The future of methane
Like other greenhouse gases, methane itself isn’t the problem. Natural methane
sources include marshland, termites, permafrost and more — it’s a natural
product of various biological processes that have been going on as long as life
itself. What’s not normal is how quickly we’re pushing ecosystems toward a
methane-emitting tipping point.
“We have growing evidence that some of these systems are going to emit more
methane than they were,” Reinhardt said. “Even though they’re natural emissions,
they’re doing an unnatural thing.”
Scientists have been warning for years about a ticking “methane time
bomb” in
the thawing
Arctic;
and changes in temperature and precipitation in tropical wetlands are also being
studied
closely. Reinhardt urges immediate and sweeping action to eliminate human-caused
methane emissions to stave off potentially disastrous cascading effects, as well
as secure a half-degree buffer against future warming.
“Given the time sensitivity that we have here, it’s really important that we
mitigate what we can with the solutions we have available today while also
investing in [further] solution development,” Reinhardt said.
One of those solutions will tackle the problem of
aerosols (defined here as a
suspension of particles in the atmosphere vs the propellant used in spray cans),
which help to mask the effects of climate
change.
Ironically, as we decarbonize, fewer aerosols will be co-produced — meaning
greenhouse gases will have an even greater impact in the future than they do
now. Aerosols such as sulfur dioxide are largely co-emitted with CO2. Sulfur
dioxide’s lifespan is on the order of days, not decades; so, when aerosols stop
being emitted, warming is immediately accelerated. That doesn’t cancel the
mandate to decarbonize, Reinhardt asserts; but the world should expect rapidly
accelerated warming as masking aerosols stop being emitted.
“People are increasingly worried that the next few years we’re going to be
seeing much faster warming than what has happened in the past,” she said.
But removing our methane emissions could help flatten the heating bump as
aerosols fizzle out of the atmosphere.
Unfortunately, the methane discussion is still relatively new; so measuring and
predicting its effects often gets wedged into metrics optimized for CO2.
Reinhardt and
others
are calling for different ways to measure global warming potential of various
greenhouse gases, with separate metrics for long-lived (ex: CO2) and short-lived
(ex: methane) gases. Policy wonks and scientists are still debating what kind of
a metric should be developed for short-lived gases such as methane; but they
agree that we should be setting both long-term and short-term goals as opposed
to single, cumulative metrics such as global warming potential
(GWP).
“We should be setting separate targets for long-lived and short-lived climate
pollutants, so that we can best ensure that we are controlling both and not
creating tradeoffs,” Reinhardt said.
Get the latest insights, trends, and innovations to help position yourself at the forefront of sustainable business leadership—delivered straight to your inbox.
Christian is a writer, photographer, filmmaker, and outdoor junkie obsessed with the intersectionality between people and planet. He partners with brands and organizations with social and environmental impact at their core, assisting them in telling stories that change the world.
Published May 12, 2023 8am EDT / 5am PDT / 1pm BST / 2pm CEST