How Does The Carbon Cycle Impact Humans?

The carbon cycle is the process by which carbon moves through Earth’s various systems. Carbon is an essential element that is found in all living things and helps support life on Earth.

Carbon cycles between the atmosphere, ocean, land, plants, animals and fossil fuel deposits over periods of time. The basic carbon cycle starts with plants absorbing carbon dioxide from the atmosphere through photosynthesis. Some of this carbon then passes to animals when they consume plants. Carbon returns to the atmosphere when plants and animals respire, releasing carbon dioxide. When plants and animals die, some of their carbon becomes trapped in sediments, which may eventually turn into fossil fuels like oil and coal over millions of years. Burning of fossil fuels by humans then releases carbon back into the atmosphere at a much faster rate than natural processes.

Photosynthesis

Photosynthesis is the process plants use to convert sunlight, water, and carbon dioxide into energy and oxygen. During photosynthesis, plants absorb carbon dioxide (CO2) from the atmosphere through tiny pores in their leaves called stomata. The CO2 molecules combine with water and light energy to produce glucose (sugar) for the plant to use as food. Oxygen is released as a byproduct of photosynthesis.

This process removes massive amounts of CO2 from the atmosphere each year. Scientists estimate that land plants and phytoplankton (microscopic plants) in the ocean absorb 110-120 billion metric tons of CO2 annually through photosynthesis. This natural process serves as a carbon “sink” that takes CO2 out of the air and locks it away in plant matter. Without photosynthesis, CO2 would continue building up in the atmosphere more rapidly.

Respiration

Humans and animals release carbon dioxide (CO2) through the process of respiration. Respiration is the process by which organisms convert oxygen and carbohydrates into carbon dioxide, water, and energy. When we breathe, we inhale oxygen and exhale carbon dioxide. This carbon dioxide is added to the atmosphere through our breath. The CO2 molecules we exhale come from the food we eat. Plants absorb carbon dioxide during photosynthesis, incorporate the carbon into carbohydrates like glucose, and release oxygen back into the air. When we eat plants, or other organisms that eat plants like meat, we are consuming those carbohydrates that contain carbon. Then through cellular respiration, our bodies break down those carbohydrates by combining them with oxygen to produce energy, water, and carbon dioxide as waste. The carbon dioxide gas we exhale is the same carbon that was originally absorbed from the air by plants. In this way, through the processes of respiration and photosynthesis, carbon cycles between plants, animals, and the atmosphere. Human respiration makes a significant contribution to the amount of carbon dioxide in the atmosphere.

Fossil Fuels

Fossil fuels like coal, oil and natural gas contain carbon that has been stored underground for millions of years. Humans have burned massive amounts of these fuels since the Industrial Revolution, releasing huge quantities of CO2 into the atmosphere.

When fossil fuels are extracted and burned for energy, the carbon stored inside them combines with oxygen in the air to create CO2. This CO2 is released into the atmosphere, increasing the concentration of CO2 significantly.

Before the Industrial Revolution, atmospheric CO2 was around 280 parts per million (ppm). Today it is over 400 ppm and rising fast. The majority of this increase comes from burning fossil fuels like coal and oil, which has disrupted the natural carbon cycle by pumping out ancient carbon at an alarming rate.

Deforestation

Cutting down forests has a major impact on the carbon cycle and CO2 levels. Trees play a vital role in absorbing CO2 from the atmosphere through photosynthesis. The larger the forest, the more CO2 it can absorb. When forests are cleared, whether for logging or agriculture, there are fewer trees available to perform this critical function.

Deforestation is a massive contributor to increased CO2 levels around the world. It’s estimated that 15% of global CO2 emissions result from deforestation. As more forests disappear each year, the Earth loses an essential carbon sink. Less CO2 is absorbed and more remains in the atmosphere. This accelerates the greenhouse effect and global warming.

Preserving forests is crucial for maintaining balance in the carbon cycle. Old growth forests are especially important, as mature trees absorb significantly more CO2 than younger trees. Policies and initiatives to curb deforestation and implement reforestation can help restore forests as carbon stores. But preventing further loss of forests is vital to avoid dangerous CO2 buildup.

Ocean Absorption

The oceans play a crucial role in regulating the amount of carbon dioxide in the atmosphere. Ocean water naturally absorbs CO2 from the air. Through the process of dissolution, CO2 gas molecules dissolve into the ocean’s surface waters. The oceans currently absorb over a quarter of the CO2 emitted from human activities annually.

As more CO2 enters the atmosphere through fossil fuel burning and deforestation, more of it is dissolving into the oceans. Absorption happens more quickly in cold polar waters. This natural oceanic absorption significantly reduces the CO2 levels in the atmosphere and slows the rate of climate change. However, increased absorption leads to ocean acidification, negatively impacting marine ecosystems.

Climate Change

Increased carbon dioxide in the atmosphere is a major contributor to climate change. CO2 is a greenhouse gas, meaning it absorbs and traps heat from the sun. As human activities like burning fossil fuels release large amounts of CO2 into the atmosphere, more heat is trapped, causing global temperatures to rise. This leads to changes in climate patterns around the world.

Higher concentrations of CO2 act like a blanket enveloping the earth, preventing heat from escaping into space. More heat is retained within the atmosphere, land and oceans. The planet’s average temperature has already risen by 1°C compared to pre-industrial levels. Climate scientists project it could increase by 1.5°C between 2030 and 2052 if major reductions in CO2 emissions don’t occur.

Rising temperatures lead to melting glaciers and ice sheets, increasing sea levels. Changing rainfall patterns disrupt agriculture and food supplies. Extreme weather events like storms, droughts and heatwaves become more frequent and intense. All these impacts threaten human health, food security, biodiversity and infrastructure. Urgent action is needed to mitigate climate change by transitioning from fossil fuels to renewable energy sources.

Ocean Acidification

As carbon dioxide emissions have increased over the past century, the oceans have absorbed a significant amount of the excess CO2 from the atmosphere. While the oceans help reduce the amount of CO2 in the air, this comes at a steep cost. When CO2 dissolves into seawater, chemical reactions occur that reduce the pH and increase the acidity of the water. This process is known as ocean acidification.

More acidic ocean waters have major detrimental effects, especially on organisms that build shells out of calcium carbonate like corals, oysters, clams, and plankton. The increased acidity interferes with their ability to form protective shells, causing the shells to dissolve faster than they can be rebuilt. This leaves these creatures vulnerable to predators, infections, and other threats.

The impacts on these foundational marine organisms and plankton can ripple up the food chain, threatening food supplies and economies that depend on healthy oceans. Researchers estimate that ocean acidity has already increased by about 30 percent since pre-industrial times. If carbon emissions continue to rise, ocean acidity could increase by 100-150 percent by 2100 compared to pre-industrial levels. This would cause enormous harm to ocean ecosystems around the world.

Health Impacts

The increase in carbon dioxide emissions from human activities has led to rising global temperatures that profoundly impact human health. As the climate warms, heat waves are becoming more frequent and intense. Extreme heat can cause heat stroke, exhaustion, cramps, and swelling. It can also worsen pre-existing conditions like cardiovascular and respiratory diseases. High temperatures put strain on the heart and lungs as the body attempts to cool itself down through increased blood circulation and respiration.

Higher pollen counts and longer pollen seasons due to climate change have increased allergic illnesses like hay fever and asthma. Rising temperatures allow pollen producing plants like ragweed to grow faster and produce more pollen over longer periods. Increased exposure to pollen triggers allergic reactions like sneezing, runny nose, irritated eyes, and bronchial constriction.

Climate change has also expanded the geographic range and seasonality of many infectious diseases. Warmer weather allows disease carrying insects like mosquitos to proliferate and spread to new regions. This increases the transmission of vector-borne illnesses like malaria, dengue fever, Lyme disease, and West Nile virus to wider populations. Extreme weather events like flooding can further spread water-borne diseases.

Conclusion

To conclude, the carbon cycle is intrinsically linked to human activities and has significant impacts on our health and environment. By burning fossil fuels, deforestation, and altering natural carbon sinks, humans have increased the amount of CO2 in the atmosphere, amplifying the greenhouse effect and accelerating climate change. This leads to rising sea levels, more extreme weather, ocean acidification harming marine life, and increased spread of diseases. However, by transitioning to renewable energy sources, planting more trees, protecting forests, and finding ways to capture carbon, we can mitigate some of these impacts and work toward stabilizing the carbon cycle. More research and initiatives focused on reducing human carbon emissions are still needed to fully understand and address the carbon cycle’s complex interactions with humanity.