Are we breathing our way to global warming?
Breathing: it’s something we all do without thinking, a natural, life-sustaining process. But could it also be contributing to global warming? According to a new study published in the journal PLOS One, the answer might be yes albeit in a small way.
Researchers in the United Kingdom have revealed that humans exhale trace amounts of methane (CH₄) and nitrous oxide (N₂O), two powerful greenhouse gases.
While these emissions make up just 0.1% of the UK’s total greenhouse gas emissions, the findings raise some interesting questions about our role in climate change — even when we’re just breathing.
The science of breathing and greenhouse gases
When we breathe in, oxygen enters our lungs and is transferred to our bloodstream. In return, carbon dioxide (CO₂) — a waste product of cellular respiration — is released.
This exchange is well-known and, like all CO₂ emissions, plays a role in global warming.
But the new study, led by Dr Nicholas Cowan from the UK Centre for Ecology and Hydrology in Edinburgh, focused on two less-discussed gases: methane and nitrous oxide.
Both are much more potent greenhouse gases than CO₂, even in tiny amounts. Methane, for instance, is about 25 times more effective at trapping heat in the atmosphere than CO₂, while nitrous oxide is 300 times more potent.
Cowan explained: “We would urge caution in the assumption that emissions from humans are negligible. Even if small, they add up when considered alongside other sources.”
The researchers collected breath samples from 104 adult volunteers in the UK and analysed the concentrations of methane and nitrous oxide. Here’s what they found:
Nitrous oxide (N₂O): Every single participant exhaled nitrous oxide.
Methane (CH₄): Only 31% of participants exhaled methane, but those who didn’t were still likely to release it through other means — yes, we’re talking about burping and farting.
The study estimated that human breath contributes about 0.05% of the UK’s methane emissions and 0.1% of the UK’s nitrous oxide emissions. While these numbers sound small, researchers say they shouldn’t be dismissed entirely.
What if I changed my diet?
If you’re thinking this might be another reason to embrace a plant-based diet or cut back on meat, think again. The study found no significant difference in methane or nitrous oxide emissions between vegetarians and meat-eaters.
“Concentration enhancement of both CH₄ and N₂O in the breath of vegetarians and meat consumers are similar in magnitude,” the researchers noted.
So, while switching to a vegetarian diet has plenty of environmental benefits, it probably won’t change how much methane or nitrous oxide you’re exhaling.
Humans aren’t the only ones exhaling greenhouse gases. Livestock and wild animals also emit methane and nitrous oxide through their breath, burps and flatulence. Cows, in particular, are known for their methane-heavy burps, which are a significant source of global emissions.
The study suggests that emissions from wild animals and livestock could account for more than 1% of nitrous oxide emissions in the UK.
While human contributions are much smaller, it’s still a reminder that every organism on Earth plays a role in the planet’s delicate balance.
Should we be worried?
Before you start holding your breath to save the planet, take a deep one and relax. The emissions from human breathing are minuscule compared to other sources of greenhouse gases, like burning fossil fuels, deforestation, and industrial agriculture.
Cowan and her team stressed that their study isn’t meant to alarm people but to highlight a previously overlooked source of emissions.
“The evidence of planet-killing breathing is pretty clear, but it needs to be viewed in context,” she said.
In other words, humans aren’t the villains of the climate crisis just because we breathe.
However, the study does serve as a reminder that tackling climate change requires a broad focus, addressing everything from industrial emissions to individual behaviours.
What can we do to reduce our carbon footprint?
While you don’t need to stop breathing (obviously!), there are plenty of other ways to reduce your carbon footprint:
Drive less: Walk, bike or use public transport when possible.
Switch to renewable energy: Install solar panels or choose green energy providers.
Reduce waste: Compost food scraps, recycle, and cut back on single-use plastics.
Eat sustainably: While your breath won’t change, eating less meat and dairy can significantly reduce emissions from agriculture.
Support reforestation: Trees absorb CO₂ and help offset emissions.
Let’s face it, humans have enough to worry about without adding “breathing” to the list of climate concerns. Still, it’s fascinating to learn how even the most mundane aspects of our lives can connect to global challenges like global warming.