“The heavens declare the glory of God.” With this proclamation David opens Psalm 19, which“celebrates the glory of God as manifested in his works” and “the knowledge of God which shines forth more clearly in his word,” as John Calvin says in his commentary. There is no doubt that this proclamation “includes by synecdoche the whole fabric of the world.” Within this fabric is the Element Carbon, known in part across the disciplines, yet unknown broadly as Gift. Here I describe seven facets of this gift including its being the principal thermostat of Our Common Home.
Seven Facets of Carbon
1. Carbon dioxide is ubiquitous and persistently accessible to plants everywhere.—Carbon’s accessibility on Earth has an unbroken history and held at an atmospheric concentration of 2.8 hundredths of one percent (280 parts per million) for 10,000 years. Its consistent omnipresence as a noncondensing and noncombustible atmospheric gas are essential to life, moment by moment. This extends into the waters where its high solubility and reversibly forming bicarbonate maintains a steep air-to-water gradient that drives it into natural waters everywhere.
2. Carbon dioxide is the exclusive source of life’s structural & respiratory carbon, making it uniquely fit for all living things.—Already in 1909, we knew carbon as “in some sense the basal material or the fundamental food of the organic kingdom.”1Sunlit green plants assimilate it by photosynthesis while below the oceanic photic zone organisms assimilate it by chemosynthesis —thus effectuating construction and energizing life. Carbon’s single, double, and triple bonds interlink, forming molecular backbones and skeletons that support carbon-based life. Tts dioxide, CO2 and its bicarbonate exclusively provide carbon for life’s structural architecture and are uniquely fit for empowering life.
3. Carbon dioxide buffers the oceans, keeping them close to neutrality.—“The most striking of all the ocean’s qualities is its constancy,” wrote Lawrence Henderson, in The Fitness of the Environment in 1913. At its center is the bicarbonate-buffer system that keeps ocean pH slightly alkaline—depicted in the reversible equation:
CO2 + H2O <===> H2CO3 <===> H+ + HCO3
carbon dioxide water carbonic acid hydrogen ion bicarbonate ion
where CO2 reacts with water to form hydrogen and bicarbonate ions via carbonic acid. Addition of acids or bases shifts this reversible reaction, maintaining a hydrogen concentration near neutral (pH about 8.1). This provides “a lodgment for life” wrote Henderson, who pronounced, “No philosopher’s or poet’s fancy, no myth of a primitive people has ever exaggerated the importance, the usefulness, and above all the marvelous beneficence of the ocean for the community of living things.”2
4. Carbon dioxide controls the pH of the blood.— As carbon is key to regulation of ocean pH, so also for blood pH, keeping it near neutral (about 7.4) by this bicarbonate-buffer system. Described by Henderson,3 CO2 is exchanged with blood via lungs, gills, and moist skin—while bicarbonate ions formed by this buffer are excreted by gills or kidneys. When acids or bases are added, pH remains nearly constant, being buffered. Amazed at this system and the solvent power of water in the ocean and blood, Henderson declared these “two of the great factors of the geological and biological history of the earth.”
5. Carbon dioxide and water vapor selectively absorb Earth’s outgoing radiation, retaining heat that makes Earth habitable.— My University of Wisconsin colleague, Verner Suomi, built radiometers for Earth-orbiting satellites, measuring outgoing radiation from the top of Earth’s atmosphere (TOA) at 240 watts per square meter (w/m2), equivalent to a very cold TOA at -18 deg C (-0.4 deg F).4 Yet, Earth’s surface is about 33 C degrees warmer, at about 15deg C (59 deg F)— equivalent to outgoing radiation of 390 w/m2 —150 w/m2 less than the TOA.5 Why this difference of 33 Celsius degrees and 240 watts per square meter? Earth’s atmosphere.
In 1896, Swedish scientist, Svante Arrhenius, wrote: “The selective absorption of the atmosphere is…not exerted by the chief mass of the air, but in a high degree by aqueous vapour and carbonic acid [carbon dioxide], which are in the air in small quantities.”6 And, “The influence of this absorption is comparatively small on the heat from the sun, but must be of great importance in the transmission of rays from the earth.” These two gases are the principal absorbers of these “outgoing rays” making Earth nearly 60 Fahrenheit (33 Celsius) degrees warmer than otherwise.
6. Carbon dioxide is the principal thermostatic controller of Earth’s temperature.—The two major IR-active gases are carbon dioxide and water vapor, but have very different properties, well summarized by NASA scientists at the Goddard Space Flight Center in 2010 in the journal Science, with the telling title, “Atmospheric CO2: Principal Control Knob governing Earth’s temperature.” They showed that removal of all carbon dioxide from the atmosphere, makes water vapor the only major greenhouse gas, but it condenses every time it cools, forming water and ice, decreasing toward zero over about 50 years. While it must be warmer to change to vapor, without CO2, it is continuing to cool, forming what Goddard scientists call snowball Earth. But putting CO2 back provides the needed warming for water once again to vaporize, meaning that CO2 is the thermostat and water vapor a very strong amplifier. In other words, the thermostat doesn’t only help heat the house, but sets the conditions for the regulating its temperature. This occurs because for every 10-degree C fall in temperature, the capacity of the atmosphere to hold water vapor is reduced, by about half, moving near zero at 32 deg F (0 deg C). Putting CO2 back returns the thermostat into service.
What happens if we increase carbon dioxide above 280 ppm? As we now turn up the thermostat above what it has been for 10,000 years, the atmosphere warms, and its water-holding capacity doubles with every 10-degree rise in temperature (increasing 7 per cent for every Celsius degree increase (1.8 F degrees). In this, it holds more water and can precipitate more. As water vapor condenses in the atmosphere; carbon dioxide does not and the interplay between this condensing gas and non-condensing gas has kept Earth’s thermostat at 280 ppm during the past 10,000 years with great benefit to human civilization.
7. Carbon dioxide effectuates stellar triple-alpha fusion in providing carbon for all of life.—At the beginning of every thing, hydrogen, helium, and some lithium were created. Pure energy was turned into matter. But no carbon was present. Harvard astronomer, Owen Gingerich describes how this challenged British astronomer Fred Hoyle to announced “Since we are surrounded by carbon in the natural world and are ourselves carbon-based life, the stars must have discovered a highly effective way of making it, and I am going to look for it.” He made a prediction and asked physicist Willy Fowler to test it at the Cal Tech accelerator. And “there it was. Not only was it there, but at precisely the right energy level. Four percent lower, and there would be essentially no carbon.”7
In stars called red giants at 100 million degrees Kelvin, two Helium4 nuclei, also called alpha particles, fuse to form Beryllium8 and at a precise energy level fuse with a third Hellium4 nucleus to form Carbon12. This “triple-alpha process” is the origin of the carbon that enables all life of Earth.8Way before Earth was formed—this process began producing Carbon— thereby effectuating (making serviceable) life on Earth, including the six facets summarized above.
Responding to Carbon’s Invitation
All seven facets of carbon and its dioxide—as we behold them—reflect the integrative beauty of a remarkable chemical element. They make us think of our Star, the Sun, whose radiation empowers Earth and its life and praise the Son by whom all things were made. Carbon’s invitation is lively and pervasive, reflecting its remarkable support of life, compelling us to conserve and to keep its service to Our Common Home, imaging God’s gift and bountiful care.
- Chamberlin, Thomas C. and Rollin D. Salisbury, 1909. Geology. New York: Henry Holt & Co., p. 639.
- Henderson, Lawrence J. 1913. The Fitness of the Environment: An Inquiry into the Biological Significance of the Properties of Matter. New York: Macmillan Company, New York, 1913, 190
- Henderson, L. J. 1928. Blood: A Study in General Physiology. New Haven: Yale University Press.
- Computed by the Stefan-Boltzmann Law
- Vonder Haar, Thomas H. and Verner E. Suomi. 1971. Measurements of the Earth’s Radiation Budget from Satellites during a Five-Year Period. Part I: Extended Time and Space Means. J. Atmospheric Sciences 28(3):306-314. (0.34 cal cm-2 min -1 in Table 2, converted to 237.32 watts per square meter.)
- Arrhenius, S. 1896. On the Influence of Carbonic Acid in the Air Upon the Temperature of the Earth. Philosophical Magazine 41: 237-276.
- Gingerich, Owen. 2014. Do the Heavens Declare the Glory of God” Perspectives on Science and Christian Faith 65(2):113-117, 115.
- Burbridge, E. Margaret, G. R. Burbridge, William A. Fowler, and Fred Hoyle. 1957. Synthesis of the Elements in Stars. Reviews of Modern Physics 29(4):547-654, 550.