Why Is The Carbon Cycle Important Short Answer?

The carbon cycle is the biogeochemical cycle by which carbon is exchanged between Earth’s biosphere, geosphere, hydrosphere, and atmosphere. Carbon is an essential element for life on Earth and cycles through both living and non-living components of the planet.

The cycle begins with atmospheric carbon dioxide (CO2) being absorbed by plants through photosynthesis or directly dissolving into the oceans. The carbon is then transferred between organisms through food webs and cellular respiration. It is also released back into the atmosphere through natural processes like respiration and decomposition, as well as through human activities such as the burning of fossil fuels.

In the atmosphere, carbon dioxide gas makes up a very small percentage of the overall atmospheric gases. However, it plays an enormously important role in trapping heat close to Earth’s surface through the greenhouse effect. The exchange of carbon between Earth’s systems maintains an overall balance that regulates global temperatures and climate.

Role in Climate Regulation

The carbon cycle plays a crucial role in regulating Earth’s climate by controlling the amount of carbon dioxide (CO2) in the atmosphere. CO2 is a greenhouse gas that traps heat and warms the planet. When CO2 levels rise, more heat is retained, causing global temperatures to increase.

The primary way CO2 is added to the atmosphere is through burning fossil fuels like coal, oil, and natural gas. Deforestation also releases large amounts of CO2. The ocean and terrestrial ecosystems help regulate CO2 through carbon sequestration, absorbing it from the atmosphere through photosynthesis and storing it in biomass like trees and marine organisms.

However, human activities are disturbing the natural balance of the carbon cycle by putting more CO2 into the air than natural sinks can remove. This anthropogenic increase in atmospheric CO2 is the main driver of climate change. A balanced carbon cycle is therefore critical for stabilizing Earth’s climate and averting the most damaging impacts of global warming.


One of the most important roles carbon plays in the carbon cycle is during photosynthesis. Photosynthesis is the process plants use to convert sunlight into chemical energy. Plants absorb carbon dioxide (CO2) from the atmosphere through tiny pores in their leaves. The CO2 molecules combine with water from the soil and energy from the sun to produce glucose (food for the plant) and oxygen.

This chemical reaction is crucial for life on Earth. Through photosynthesis, plants use the carbon from CO2 to build their stems, roots, leaves and fruits. At the same time, photosynthesis releases oxygen into the atmosphere. The oxygen gas produced through photosynthesis is what animals and humans breathe.

Photosynthesis also results in the storage of carbon in plants. As plants grow bigger, the carbon that makes up their tissues comes from the CO2 absorbed during photosynthesis. Photosynthesis therefore acts as a carbon “sink,” taking carbon dioxide out of the atmosphere and depositing it in plant biomass.

Cellular Respiration

Cellular respiration is an important process in the carbon cycle that releases carbon dioxide (CO2) into the atmosphere. During cellular respiration, cells break down glucose and produce ATP for energy. This process occurs in all living organisms, including animals, plants, bacteria and fungi.

Both plants and animals take in oxygen (O2) and release CO2 through respiration. For most animals, respiration occurs continuously to provide the energy they need to live and move. Plants also respire continuously to provide energy for basic cell functions. However, plants release the majority of their CO2 during the night when photosynthesis has stopped. The CO2 released from respiration is then absorbed by plants for photosynthesis during the day, creating a cycle of carbon between plants and animals.

Overall, cellular respiration plays a key role in the carbon cycle by releasing CO2 into the atmosphere. The balance between photosynthesis and respiration maintains stable levels of atmospheric CO2. However, increases in respiration due to human activities have contributed to rising CO2 levels and climate change. Understanding the role of cellular respiration in the carbon cycle is therefore essential.


Combustion releases carbon stored in fossil fuels, including coal, oil, and natural gas, into the atmosphere. When fossil fuels like gasoline, diesel, and coal are burned, chemical reactions with oxygen produce carbon dioxide (CO2) and other gases, converting carbon that had been stored underground for millions of years back into atmospheric carbon. This dramatically increases the flow of CO2 into the atmosphere. Before the Industrial Revolution, natural amounts of CO2 released from the burning of wood fires, forest fires, etc. were roughly balanced by CO2 absorbed and sequestered by ocean phytoplankton and plants. However, the massive amount of CO2 emissions from burning fossil fuels for energy, heat, transportation, and industry over the last two centuries has rapidly added carbon back into the atmosphere and oceans faster than it’s being removed. This human-caused disturbance to the carbon cycle is a major factor driving global climate change.

Ocean-Atmosphere Exchange

The oceans are an important part of the carbon cycle, acting as another carbon reservoir that exchanges CO2 with the atmosphere. CO2 dissolves into ocean water, where it reacts to form carbonic acid. The dissolved CO2 can then be used by marine organisms for photosynthesis or stored in deep ocean waters.

The oceans both absorb and release CO2 from the atmosphere. When atmospheric CO2 is high, more CO2 dissolves into the oceans. Colder water can also dissolve more CO2. As atmospheric CO2 rises due to human emissions, the oceans act as a carbon sink, absorbing CO2 and storing it. However, as water warms, it can no longer hold as much CO2, causing the oceans to release CO2 back into the atmosphere. The ocean carbon cycle helps regulate Earth’s temperature and climate by absorbing and releasing CO2.


Decomposition of organic matter by bacteria and fungi is another key process in the carbon cycle that releases CO2. When organisms like plants and animals die, they become food for decomposers like bacteria and fungi. These decomposers break down the dead organic matter through digestion and release carbon back into the atmosphere as CO2 gas.

For example, a dead tree log on the forest floor is broken down by decomposers, releasing the carbon stored in the tree’s biomass back into the air. Similar decomposition happens in grasslands, aquatic ecosystems like the ocean, and even in our own bodies when bacteria decompose organic waste. The rate of decomposition depends on environmental factors like temperature, moisture, soil quality, and the type of organic matter. But overall, the decomposition process steadily returns carbon in organic matter to the atmosphere.

Carbon Sequestration

Carbon sequestration plays a key role in regulating the amount of carbon dioxide in the atmosphere. It refers to the long-term capture and storage of carbon in plants, soils, geologic formations, and the ocean. This process removes CO2 from the atmosphere and stores it in what are known as “carbon sinks.”

Terrestrial ecosystems like forests, wetlands, and soils absorb massive amounts of carbon through photosynthesis. Plants use CO2 to grow and build plant tissue. Much of this carbon ends up stored in roots, stems, branches and leaves. Forests are particularly important carbon sinks as trees can live for centuries, locking away carbon for long periods.

The ocean is another major reservoir for carbon. It absorbs CO2 from the atmosphere through gas exchange across the air-sea interface. This CO2 dissolves in seawater and can be stored for hundreds to thousands of years. Some carbon makes its way to the deep ocean by the biological pump, transported via sinking organic matter from dead plankton.

Geologic sequestration involves injecting CO2 into underground geologic formations for secure storage. Depleted oil and gas reservoirs, deep saline formations, and unmineable coal seams are potential storage sites. When CO2 is injected it becomes trapped underground and isolated from the atmosphere.

Enhancing natural and engineering carbon sequestration provides a way to mitigate climate change. Removing excess carbon from the atmosphere via storage in sinks and reservoirs helps restore balance to the carbon cycle.

Human Impact

Human activities have substantially impacted the carbon cycle, mainly through burning fossil fuels like coal, oil, and natural gas. When we burn fossil fuels, carbon that has been stored underground for millions of years is released into the atmosphere as carbon dioxide. Since the Industrial Revolution began in the 1800s, humans have increased the amount of carbon dioxide in the atmosphere by over 40%. This has major implications for the carbon cycle.

The increase in atmospheric carbon dioxide caused by burning fossil fuels is the primary driver of human-caused climate change. Carbon dioxide is a heat-trapping greenhouse gas, so increased levels cause more heat to be retained in the atmosphere and less to escape back into space. This enhances the natural greenhouse effect and causes global temperatures to rise. The rate at which humans are adding carbon dioxide to the atmosphere is drastically faster than natural processes can remove it. This human-caused disruption of the carbon cycle leads to climate change impacts like rising sea levels, melting glaciers, more extreme weather events, and ocean acidification.

Importance of Balance

A balanced carbon cycle is critical for maintaining a stable climate and supporting life on Earth. The movement of carbon between the atmosphere, oceans, ecosystems and geosphere acts as a global thermostat, regulating Earth’s temperature.

Without a balanced carbon cycle, excess carbon dioxide can build up in the atmosphere and oceans, causing global temperatures to rise rapidly. This can lead to severe climate change impacts like melting glaciers, rising seas, more extreme weather, and habitat loss. Even small disruptions to the carbon cycle get amplified over time and can throw off the entire planet’s climate equilibrium.

The carbon cycle also provides the carbon atoms that make up the basis of all life. Carbon forms the backbone of key biological molecules like proteins, fats, DNA and RNA. It moves through the food chain to sustain every living thing. An imbalance in the carbon cycle affects the availability of this fundamental element for plants and ecosystems.

For all these reasons, the carbon cycle must remain in harmony through natural processes of carbon exchange. Human activities like burning fossil fuels have severely disrupted this balance by overloading the atmosphere with extra carbon. Restoring equilibrium to the carbon cycle through reduced emissions and carbon sequestration is now essential for the continued prosperity of life on Earth.

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