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The Carbon Cycle


‘Circularity’ is the principle that each element on a chain serves as raw material or input for the next until the chain closes its loop. Circular-design uses this principle to create product-systems that generate, preserve, and compound value, without creating waste or dead-ends. Circularity can be seen most intensely in Earth’s Carbon Cycle.

Forged by aging stars, carbon is the fourth most abundant element available in the Universe. It forms the building block of all life on Earth and is found stored in rocks, the ocean, the atmosphere, plants, soil, and deep underground in fossil fuels. 

Carbon flows between each reservoir via an exchange called the carbon cycle. With both slow and fast-paced components, the processes that remove carbon from one state add it back to another. 


The Slow Carbon Cycle / From the Atmosphere to the Lithosphere

Carbon cycles from the atmosphere to the lithosphere using rain. Carbon in the atmosphere combines with water from rain to form carbonic acid. When it falls to the surface, the acid dissolves rocks (chemical weathering) and releases calcium, magnesium, potassium, or sodium ions. 

Once in the ocean, the calcium ions (carried there by rivers) combine with bicarbonate ions to form calcium carbonate, a process done mostly by calcifying organisms (such as corals) and plankton. After they die, these organisms sink to the ocean floor, creating layers of shells and sediment, fusing into rock over time, and storing carbon as stone. 

While approximately eighty percent of carbon-containing rock forms this way, the rest results from living things embedded in layers of mud over millions of years, creating oil, coal, and natural gas.

Slowly, the lithosphere returns carbon to the atmosphere via volcanoes. When the plates beneath our land and ocean surfaces collide, one sinks beneath the other, melting the rock above. The molten rock recombines into silicate minerals and is released along with carbon dioxide when the volcano erupts. The gas escapes to the atmosphere; the fresh silicate rock covers the land, beginning the cycle again.  

The Fast Carbon Cycle / Movement of Carbon through Earth’s lifeforms

1,000 to 100,000 million metric tons of carbon move through the fast carbon cycle every year. The fast carbon cycle mainly consists of plants and phytoplankton that absorb carbon dioxide from the atmosphere and store it into their cells. They combine energy from the Sun, carbon dioxide from the air (CO2), and water from the Earth to form sugar (CH2O) and oxygen. 

CO2 + H2O + energy = CH2O + O2 

Plants use the sugar they make for the energy they need to grow. Animals and people eat the plants (or plankton) to break down the plant sugars and gain the energy stored. When plants and plankton die, the decay combines their sugars with the oxygen in the air to release as water, energy, and carbon dioxide back into the atmosphere. 

CH2O + O2 = CO2 + H2O + energy 

Humans, causing problems.

The fast and slow carbon cycles usually maintain steady carbon flow between the atmosphere, land, plants, and ocean carbon stores. But when disturbed, the effects ripple through all of them. While volcanoes emit between 130 and 380 million metric tons of carbon dioxide per year, humans, on the other hand, emit about 30 billion tons of carbon dioxide per year (thanks to burning fossil fuels). That is 100–300 times that of volcanoes. Of course, this problem further compounds by the fact that humans are also very busy clearing forests.

By removing forests, we eliminate the vast carbon absorption and storage capacities of our land. We then replace the dense forest vegetation with crops or pasture, comparatively processing far less carbon. Doing this also exposes the soil below, resulting in the carbon stored there (from decayed plant matter) to vent back into the atmosphere.

While fossil fuels (which take millions of years to accumulate) are essentially a part of the slow carbon cycle, by burning coal, oil, and natural gas, we accelerate this process, moving all this extra carbon into the fast cycle.

Unfortunately for us, CO2 is what controls the Earth’s temperature. Scientists have calculated that carbon dioxide causes about twenty percent of Earth’s greenhouse effects; water vapor accounts for about fifty percent, and clouds account for twenty-five percent. The rest is accounted for by small aerosol particles and other minor greenhouse gases like methane.

“Carbon is the currency of life. The rapid formation of carbon-rich topsoil is the greatest priority and opportunity of our time” – Dr. Rattan Lal 

Carbon Sequestration / Reducing Atmospheric Carbon Dioxide

One way to reduce atmospheric carbon dioxide is to increase global carbon storage in our soil. When plants (such as grasses) absorb carbon from the air for photosynthesis, not only do they use it for their growth, but they also use it in symbiosis with micro-organisms in the soil, making carbon bank deposits in exchange for various microbial nutrients. 

The organic matter from the biomass of plant roots, the agitation of grazing animals, and the manure that they leave behind all adds carbon (and other nutrition) for the soil microbes to convert into complex yet, stable carbon compounds. Collectively called humus, these carbon compounds are the backbone of building new soil, and the process of storing them is called carbon sequestration.  

As seen in old-growth forest soils and the un-plowed American prairies, soil can reach over six feet deep, indicating no limit to the soil volume that can build over time. Therefore, managing pastures in similar methods can play a vital role in this process of global land carbon sequestration. 

Much like houseplants that have growth spurts when pruned, grasslands also withstand grazing and benefit from it to grow back stronger. Fossil records show us that grasslands and ruminants co-evolved fifty-five million years ago, with one side doing the grazing and the other side being grazed. With every bite, cows trigger the plant to exchange carbon compounds with soil microbes for rapid regrowth nutrition. The grass’s photosynthesis rate goes up, which grows more grass (biomass), and removes more carbon from the air, to deposit into the soil.  

Any grazing action pushes grass back to its growth stage. As long as the grass grows actively, it continues to remove carbon from the atmosphere, sequestering it into the ground. This carbon pathway supports healthy underground ecosystems in a positive feedback loop. It builds organic matter, creates humus, and deep, fertile, well-functioning soil.  

Understanding Flow / Conscious Decision Making 

Roaming, grazing animals sequester carbon and provide us with nutritious, functional, and versatile by-products, such as milk, and wool. In old-world civilizations, such as in the Native American and Indian Cultures, grazing animals such as cows hold sacred space for this very reason. They are nature’s perfect beings, transforming energy from the Sun into nutrition for the land and everybody on it.  

Understanding natural carbon cycles makes it easier for us to make carbon-friendly decisions instead of making accidental choices that abuse the planet’s natural flow. Purchasing 100% grass-fed, free-range animal products or biodegradable and chemical-free products can quickly compound and significantly catalyze positive impact in the face of global climate change. 

To learn more about thriving soil cultures watch:

–– Presentation on Soil Health by Dr. Rattan Lal, Professor of Soil Sciences, Ohio State University and member of 
the Nobel Peace Prize-winning Intergovernmental Panel on Climate Change.



Riebeek, H. (2011, June 16). The Carbon Cycle. Retrieved September 01, 2020, from

Page, C. (2018, February 14). Carbon Mooooves. Retrieved September 01, 2020, from

Stebbins, G. (1981). Coevolution of Grasses and Herbivores. Annals of the Missouri Botanical Garden, 68(1), 75-86. doi:10.2307/2398811

Gustavus Adolphus College. (2018, October 2). Rattan Lal, Ph.D. Presenting at Nobel Conference 54 [Video]. YouTube. from

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