Humans are destroying the planet by emitting greenhouse gases. We’ve heard that time and time again. But if you stand there and do nothing but breathe … you still are emitting greenhouse gases!

But maybe not only in the way you think.

Go outside and stand there for several minutes. No external heating, no cooling, no transportation. Are you leaving a carbon footprint by producing greenhouse gases?

Sure you are!

You are no doubt aware that by simply partaking in the act of breathing, you are taking in oxygen and exhaling carbon dioxide. Your respiratory process does that.

Moreover, you are probably aware that if you perspire, or simply if a gradient exists between the moisture in your skin and the moisture in the air, and your skin’s moisture is higher, you will be providing water vapor to the atmosphere. And remember, water vapor is the most important greenhouse gas.

And yes, by simply exhaling, you also are adding water vapor to the atmosphere from the moisture in your lungs, mouth, and throat.

Obvious, right?

But what if I told you we weren’t done yet. You might think for a moment and then conclude, “Ah yes, methane.” Sure, it comes from rotting plants and burping cattle and their flatulence, and, yes, humans too. But merely breathing produces methane from humans.

How?

In a 2023 study published in the journal PLOS-One, nearly a third of the one-hundred-four Britons that were sampled were exhaling methane. The “methane producers,” as the article refers to them, were more likely to be over the age of thirty, female, and of African descent. For unexplained reasons, young Asian males produce the least amount of methane by simply exhaling.

Now, livestock ruminants such as cattle, sheep, and goats account for about twenty percent of the anthropogenic emissions of methane. Ruminants have a digestive system that allows them to break down and digest food that is undigestible by non-ruminants, such as humans. Cattle, for example, store partially digested food in one of their four stomachs and let it ferment. Later, they regurgitate the food and finish the digestive process. But the fermentation process produces methane, which is expelled through, well, both ends, if you know what I mean.

Since we have but one stomach, humans don’t participate in this process. Nevertheless, methanogenic flora in the human gut produce methane that we emit by exhaling, flatulence, and outgassing it through the skin.

We are not finished, however. The third evil gas, or the fourth greenhouse gas on our list, is nitrous oxide and, yes, humans produce it too. Virtually all people outgas nitrous oxide as they breathe. It derives from the reduction of nitrates in food and water by denitrifying bacteria in the gut and mouth. Eating vegetables rich in nitrates also increases the production of nitrous oxide.

Okay, okay, okay. But certainly, the production of methane and nitrous oxide by the human body is negligible in the grand scheme of things, right?

This study by five Scots found that Britons—standing silent in a field and doing nothing—will emit approximately 0.05% of the total methane emissions and 0.1% of the total nitrous oxide emissions in the UK. No doubt, these percentages will be higher in undeveloped and underdeveloped nations because they emit less from other sources, such as the transportation sector. Moreover, the decomposition of human sewage contributes about three percent of the total nitrous oxide emissions by humans.

But aren’t these numbers trivial?

Not according to the lead author of the article, who wrote, “We would urge caution in the assumption that emissions from humans are negligible. Even if small, they add up when considered alongside other sources.”

One news outlet discussed the article under the headline, “Are We Breathing Our Way to Global Warming,” while another led with “Humans Are Fueling Global Warming by Just Breathing.” The latter article again cited the authors of the study, who concluded that there is no link between diet and the exhalation of methane and nitrous oxide. “When estimating emissions from a population within the [United Kingdom], diet or future diet changes are unlikely to be important when estimating emissions across the [United Kingdom] as a whole,” the study determined. So, simply curbing your meat intake, therefore, is not a solution to your exhaling methane and nitrous oxide.

Again, alarmism is always the key to getting in the news. But life is characterized by altering its environment to optimize its living conditions. A philosopher and environmentalist, James Lovelock, was hired by NASA to figure out how we would determine whether life existed on a planet that was visited by a space probe. If alien life emerged from behind a rock and waved to the cameras, then we might be persuaded that it existed. But if the life were microscopic, albeit widespread, how could we detect it? Lovelock’s idea was that all life needs a fluid—either an atmosphere or an ocean, or both—to transport in raw materials and remove waste products. If the fluid on the planet is in chemical equilibrium, life is nonexistent or limited. On the Earth, our atmosphere should not have oxygen, and it should be composed largely of carbon dioxide. Plant life removes carbon dioxide and gives off oxygen, thereby showing that life exists on Earth due to the chemical disequilibrium of the atmosphere, and a similar analysis can be made for the oceans. The atmosphere of all the other planets we have visited is in chemical equilibrium, suggesting that life does not exist on them—at least not life that is widespread.

Lovelock also is famous for his simple model of Daisyworld. Daisyworld is a planet that contains only two species of daisies—one dark in color and one light. As the Sun’s output is modulated, the temperature of a similar world without daisies would follow the standard warming curve driven by the Stefan-Boltzmann radiation law. But when daisies are introduced, the temperature curve changes drastically. Under low sun conditions, dark daisies are preferred and the temperature of the planet quickly rises to the optimum growth temperature. As the sun’s output is increased, dark daisies are replaced by light daisies and the proportion of dark-to-light daisies on the planet serves to maintain a nearly constant optimum growth temperature. Although the real world does not work like Daisyworld—that is, the temperature of the Earth is not modulated by changing the reflectance of solar radiation—Daisyworld suggests that with a very simple set of equations and assumptions, life can modulate the environment to optimize its living conditions.

So, why should humans be any different? Most of us no longer live in thatched huts or hunter-gatherer societies. Civilization has changed our way of life to optimize our ability not just to survive, but to thrive. Warmer conditions have always benefited the development of civilization, and cold kills far more people than heat. By modulating the temperature of the planet by removing most of the carbon dioxide that should be in the atmosphere and emitting oxygen that we need to survive, plants make the Earth habitable for themselves—and for us as well.

The common message of this vein of research and the concomitant discussion in the popular press is that humans are destroying the planet, and the only path forward is to limit our numbers drastically. Once again, secular research argues that humans are the sole cause of our planet’s supposed distress. However, God instructs us to go forth and multiply and that children are a gift of the Lord. Limiting our numbers to save a planet from greenhouse gases when it does not need saving is not what God requires. Rather than deleting humans to save the planet on which we live, it is the humans who live on the planet who need the saving grace provided to us by our Lord Jesus Christ.

Photo by Isaac Wendland on Unsplash.