Last year a student at a nearby university complained she couldn’t focus in class; she was convinced high levels of carbon dioxide (CO2) were the cause. The entire building was immediately evacuated and tested for “toxic levels of this dangerous gas.” After determining the CO2 levels were less than 500 parts-per-million (ppm), the classroom air was considered “safe” and classes again resumed.

Recently, this same school advertised that you can now “offset carbon emissions from previously completed university-funded ground-transportation and air travel trips” — by filling out a “travel carbon offsets” form, available in their “Sustainability Office.” Plus, this school is offering a course on “how to lower your carbon footprint.”

National Association of Scholars is planning a meeting to discuss indoor CO2 levels, because they “may reach levels harmful to cognition by the end of this century, and the best way to prevent this hidden consequence of climate change is to reduce fossil fuel emissions.” A publication this week in Nature Climate Change states that “government policies and human activity data, due to decreases in travel during forced COVID-19 confinements, have decreased daily global CO2 emissions by ~17% to ~25% by early April 2020, compared with mean 2019 levels.”

As I read this nonsense in the news every day, I feel like screaming: “This nonsensical obsession with CO2 and the ‘carbon footprint’ is absolute insanity! Where has common sense gone?” Doesn’t anyone remember — from grade school and high school biology — what they learned about plant photosynthesis requiring CO2 and all animals requiring oxygen (O2) and exhaling CO2? Life on this planet is carbon-based; if we were not carbon-based, the next available tetrahedral element (having four chemical bonds) in Mendeleev’s Periodic Chart is silicon — in which case we would be able to live on the sun’s surface!

CO2 levels in our lungs reach ~40,000-50,000 ppm, which causes us to inhale our next breath. One of the first things medical students learn in respiratory physiology — is that the carotid body (small cluster of chemoreceptor cells, located at bifurcation of the common carotid artery running along both sides of neck) detects changes in arterial blood flow pO2 (partial pressure of oxygen), pCO2, blood pH, and temperature. When the blood pCO2 reaches a critical level, this message is quickly sent to the medulla oblongata in the brainstem, which then sends signals our diaphragm to breathe; more O2 is needed, and excessive CO2 must be expelled.

The human breathing reflex is controlled by blood CO2 levels, not O2 levels. Too little CO2, which can happen from hyperventilating, leads to respiratory alkalosis. This is called hyperventilation syndrome — usually brought on by stress and anxiety. Symptoms include light-headedness; tingling in the fingers, toes and face; and chest pain; sometimes people fear they’re having a heart attack. Treatment for hyperventilation syndrome is to breathe into a paper bag, which increases your blood CO2 back to normal.

As the only physician on a commercial airlines cross-country flight, I was asked to examine a ~35-year-old woman who thought she was having a heart attack; the obvious diagnosis was hyperventilation syndrome (due to anxiety of meeting her inlaws for the first time). I had her breathe intermittently into a paper bag to increase her blood pCO2 levels; within ~20 minutes she was no longer symptomatic. Had no physician been on that flight, they would have diverted the aircraft to St. Louis to a waiting ambulance, rather than proceeding to Portland, OR, the scheduled destination.

Breathing is automatic (controlled by our autonomic nervous system) — meaning that we don’t think about it; it “just happens” about 16 times a minute. This is one of God’s many miracles in all animals with lungs. Heart rate, kidney blood flow, and digestion of our food — are other examples of autonomic-nervous-system regulation that constantly functions while we don’t think about it.

Today’s global atmospheric CO2 levels are about 415 ppm; at these levels CO2 remains a limiting factor for growth of farm crops and trees. Plants today are “at least 25% CO2-starved.” In fact, standard procedures for commercial greenhouse growers are to elevate CO2 to 800-1200 ppm; this enhances growth and yield ~20-50%. Indoor air routinely ranges between 500 and 2,000 ppm of CO2. Submarines regularly operate with ambient CO2 levels between 2,000 and 5,000 ppm.

In past ages, ice-core data suggest CO2 levels have been as high as 10,000-15,000 ppm (this was before humans; in fact, before mammals evolved), and plant life flourished. In recent times, “normal” CO2 ranges between ~150-180 ppm during Glacial Periods and ~280-300 ppm during Inter-Glacial Periods. Industrialization during the past 130 years has probably increased global atmospheric CO2 levels by ~135 ppm, which has improved crop growth.

To paraphrase Professor Zbigniew Jaworowski (Chair, Scientific Council of Central Laboratory for Radiological Protection; Warsaw, Poland) who testified before the US Senate Committee on Commerce, Science, and Transportation in 2004: “The basis — of most conclusions by United Nation’s Intergovernmental Panel on Climate Change (IPCC) on anthropogenic (man-made) causes, and their projections of climatic change — relies on the assumption that low levels of CO2 in the pre-industrial atmosphere represent the ‘normal’ baseline. From glaciological studies, we know this assumption is false. Therefore, IPCC projections should not be used for national and global economic planning and governmental policy.”

The atmospheric impact of CO2 on climate is overstated. Since the Little Ice Age (1300-1860), Earth has been warming naturally. As temperatures rise, CO2 in the liquid phase (oceans) moves to the gaseous phase (air); we learn this in introductory chemistry. Hence, rising global atmospheric temperatures cause CO2 to increase — not the other way around!

Carbon emissions” and “carbon footprint” as causes of global warming are nothing more than scaremongering buzzwords — created by global warming alarmists, insincere environmentalists, certain manipulative dishonest politicians, and misinformed journalists. Earth has undergone climate change and local severe weather since its formation ~4.54 billion years ago. Causes of natural variations in climate include: solar activity; cloud type and amount; radiative forcing and insolation (amount of sunlight absorbed vs amount radiated back into space); Earth’s rotation and interplay between its atmosphere and oceans; variations in precession, eccentricity and axial tilt of our planet; gravitational pull of other planets of substantial mass (especially Jupiter); and volcanic eruptions both on land and underwater.

CO2 is an odorless, tasteless, invisible non-polluting gas on which all life on Earth depends. “Smoke” from factory chimneys usually represents water vapor, not CO2. Dirty industrial fossil-fuel pollution is, of course, undesirable and causes health problems. However, many scientific lines of evidence — including geological history and basic radiation-transfer physics — show that anthropogenic CO2 emissions have negligible influence on climate, in comparison to the natural factors listed above.


  • Daniel (“Dan”) Walter Nebert is an American physician-scientist, molecular biologist, and geneticist. He has authored/coauthored publications in fields of biochemistry, molecular biology, pediatrics, developmental biology, pharmacology, drug metabolism, toxicology, mouse genetics, human genetics, evolutionary genomics, gene nomenclature, and cancer.