Carbon Dioxide Is Not Toxic, but The Moon Is

Too much of something can be bad, but too little can also be bad. We examine the influence of carbon dioxide in earth’s atmosphere.

Scientists seem conflicted about CO₂ (carbon dioxide). It gets blamed for all kinds of bad things, but with few exceptions, every living thing either takes it in or gives it off. Each one of us gives off carbon dioxide in every breath. Outside the body, CO₂ doesn’t poison us unless the ratio is bad and we can’t get oxygen, as when people enter some caves or mine shafts. The 12 soccer players and their coach trapped in a cave in Thailand for two weeks had to be resupplied with oxygen during the rescue operation, which was successful on Tuesday, to everyone’s relief (Fox News). Too much oxygen, though, can also be problematic. It could drastically aggravate the danger from wildfires. Some substances are toxic in any concentration, but others have to be considered in relation to the whole.

These days, we usually hear about carbon dioxide in relation to climate change. It is a greenhouse gas, though not nearly as potent as methane. Mars has a lot of frozen CO₂ at its poles, but no oxygen to breathe (Phys.org), and is very cold. To help illuminate CO₂‘s role in earth’s biosphere, we bring you some news items that touch on this common, simple tri-atomic molecule. What a difference adding one carbon atom to O₂ makes!

Rising carbon dioxide levels pose a previously unrecognized threat to monarch butterflies (Phys.org). Scientists at the University of Michigan found that higher CO₂ levels change milkweed, the monarch butterfly’s only food in the caterpillar stage. Under higher carbon dioxide air, milkweed produces less of the cardenolides that monarchs rely on to keep from being eaten. It also exposes them to parasites and reduces their lifespan. The scientists speculated that rising CO₂ levels might also affect other plants that humans rely on for medicines, but provided no empirical studies.

Is carbon dioxide worth a yawn? (The Conversation). For your amusement, this article by Christine Calder explores theories about a universal animal behavior – yawning. For those who look to science to provide answers about observable, repeatable phenomena that can be studied for thousands of years, her final answer is way out yawn-der.

In the past, people have had many hypotheses. As far back as 400 B.C., Hippocrates thought yawning removed bad air from the lungs before a fever. In the 17th and 18th century, doctors believed yawning increased oxygen in the blood, blood pressure, heart rate and blood flow itself. More recently, consensus moved toward the idea that yawning cools down the brain, so when ambient conditions and temperature of the brain itself increase, yawning episodes increase.

Despite all these theories, the truth is that scientists do not know the true biological function of a yawn.

Oxygen levels on early Earth rose and fell several times before the successful Great Oxidation Event (University of Washington News). We tend to assume that earth has an ideal ratio of oxygen to other gases, but the secular moyboys at UW, divining the rocks, envision big swings over vast ages. “Earth’s oxygen levels rose and fell more than once hundreds of millions of years before the planetwide success of the Great Oxidation Event about 2.4 billion years ago,” the article by Peter Kelley says. He sees trouble ahead. This announcement casts doubt on finding life on other planets by looking for oxygen. It also complicates the myth of the Great Oxidation Event (sometimes called the Great Oxygenation Event). Maybe it wasn’t so great. Maybe it was just the final tipping point in the story.

Ten products you may not realise are threatened by the CO₂ shortage (The Conversation). Mercedes Maroto-Valer is a former climate alarmist who’s had a change of heart. When she realized that carbon dioxide is what makes beer fizz, she started looking at all the things humans use CO2 for. Then she became alarmed to hear that there’s a shortage of the gas in industry.

I have found myself in a rather unexpected place over the past few days. For more than two decades, I have been incessantly proclaiming that we produce far too much carbon dioxide (CO₂) with the associated risks of global warming. But while ever more is being pumped into the atmosphere, Europe and Mexico are also running out of usable CO₂ – as several plants that produce CO₂ have closed down for maintenance.

Her list of products that depend on CO₂ is quite astonishing: everything from wine to decaf coffee to aviation fuel. Dry ice is frozen carbon dioxide; read about some of the uses that has (hint: one is to preserve bodies in the morgue). CO₂ is used for fire extinguishers, pain killers, and all kinds of foods. Agriculturalists promote plant growth by adding CO₂. Are you ready for a world with less of this useful gas?

So, I have come to realise that after all these years talking about CO₂ associated with global warming and climate change, I need to change my research narrative. Let me try this: our research is committed to ensuring that every day you have the CO₂ required for you to continue enjoying your lifestyle, from your preferred food and drink to riding your bike or even using a life jacket.

Vent from underground coal fire, Kaiparowitz Plateau, Utah (DFC)

One commenter added that CO₂ is used for leavening bread, and that underground coal fires, some of which have been burning for centuries, are a significant source of atmospheric CO₂. They are found throughout the world. Some may have been started by humans long before the Industrial Revolution. Many may have started naturally via spontaneous combustion or from lightning.

Our Toxic Moon

Dave Scott and James Irwin at work, Hadley Rille, by Apollo astronaut and artist Alan Bean.

Ever hear of “lunar hay fever”? Only 12 Apollo astronauts who walked the surface of the moon can relate to it. Lunar dust is made of small particles as sharp as broken glass. It sticks to everything and irritates tissues. An article on Phys.org says,

“Particles 50 times smaller than a human hair can hang around for months inside your lungs. The longer the particle stays, the greater the chance for toxic effects,” explains Kim.

The potential damage from inhaling this dust is unknown but research shows that lunar soil simulants can destroy lung and brain cells after long-term exposure.

We may have problems with toxins on earth, but this comparison with our next nearest planetary companion shows we have a lot to be thankful for.

Anecdote regarding the artwork above: I heard Alan Bean speak at JPL in 1998. As I got his autograph afterward for his book Apollo: An Eyewitness Account, I told him I write and speak about space, and he granted me full permission to use his artwork for my purposes. I remember him being a gracious and humble man, very talented with a brush, as is evident in the piece here. He used that talent to document the Apollo era with a level of detail and historic accuracy that only a member of the Apollo team could. He passed away on May 26.