Breathing And Pollution: Are Humans Harming The Planet?

Human activities have significantly contributed to global warming and climate change. While breathing is an essential human function, releasing almost three billion tons of carbon dioxide annually, it is not the primary cause of environmental pollution. The carbon dioxide exhaled by humans is part of a natural fast carbon cycle or carbon cycle, where plants absorb CO2 from the atmosphere during photosynthesis and store carbon in their tissues. When humans consume these plants or animals that eat them, we ingest that carbon, which is then exhaled as CO2. This cycle maintains equilibrium, ensuring that there is no net increase in atmospheric CO2 from human breathing. However, human activities like burning fossil fuels, deforestation, mining, and industrial processes significantly impact the environment, contributing to the rising global temperatures and climate change.

The carbon dioxide we exhale is from food produced by photosynthesis

The carbon dioxide (CO2) that humans exhale does not contribute to global warming. This is because the carbon in the CO2 we exhale comes from the food we eat, which can be traced back to photosynthesis. Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar. The energy stored in plants is then passed on to the animals that eat those plants. Herbivores obtain this energy by eating plants, and carnivores obtain it by eating herbivores.

During photosynthesis, plants take in carbon dioxide from the air and soil and store the carbon in their tissues. When people eat those plants, or eat the animals that ate those plants, we ingest that carbon. The carbon in the CO2 we exhale is the same carbon that was "inhaled" from the atmosphere by the plants we consume or that was consumed by the animals we eat. In this way, the carbon dioxide we exhale is from food produced by photosynthesis.

The carbon cycle is the process that moves carbon between plants, animals, microbes, minerals in the earth, and the atmosphere. Carbon is constantly moving within this cycle, but the Earth itself is a closed system, meaning it does not gain or lose carbon overall. Within the carbon cycle, the carbon dioxide we exhale returns to the atmosphere, and the cycle begins again. This natural ""fast carbon cycle"" has been at work throughout Earth's history and helps to regulate the amount of CO2 in the atmosphere, keeping the Earth's climate in balance.

In contrast, when we burn fossil fuels such as gasoline, coal, or natural gas, we are releasing carbon dioxide that forms from carbon atoms that had been removed from the atmosphere millions of years ago by photosynthesis. By burning these fossil fuels, we are increasing the current levels of carbon dioxide in the atmosphere, contributing to global warming. Unlike the carbon we exhale, which does not contribute to net increases in atmospheric CO2, the carbon released from burning fossil fuels adds to the carbon in the atmosphere.

CO2 from breathing is part of a closed-loop carbon cycle

The carbon dioxide (CO2) that humans breathe out is part of a closed-loop carbon cycle. This cycle, also known as the fast carbon cycle, has been in operation throughout Earth's history and is essential for maintaining the balance of carbon dioxide in the atmosphere. The carbon cycle is the process by which carbon moves between plants, animals, microbes, minerals in the earth, and the atmosphere.

Plants and phytoplankton are the main components of the fast carbon cycle. During photosynthesis, plants and phytoplankton absorb carbon dioxide from the air and soil and store the carbon in their tissues. Animals, including humans, then ingest this carbon by consuming plants or other animals that have eaten these plants. The carbon is then exhaled back into the atmosphere as CO2, completing the cycle.

This natural process ensures that there is no net increase in atmospheric CO2 levels due to breathing, as the carbon is simply being recycled. The carbon cycle helps to regulate the amount of CO2 in the atmosphere, which is crucial for controlling the Earth's temperature. Without greenhouse gases like CO2, the Earth would be a frozen -18 degrees Celsius.

However, human activities, such as burning fossil fuels and clearing land, have perturbed the carbon cycle. Fossil fuels contain carbon that was removed from the atmosphere by photosynthesis millions of years ago and sequestered underground. When we burn these fuels, we release carbon that would not have naturally re-entered the atmosphere for a very long time, leading to an increase in atmospheric CO2 levels and contributing to global warming.

Therefore, while the CO2 from human breathing is part of a closed-loop carbon cycle and does not directly contribute to global warming, human activities that disrupt this cycle are a significant concern for the planet's climate.

Humans account for 8.5% of global emissions by breathing

The carbon dioxide we exhale does not contribute to global warming because we also take up an equivalent amount of carbon dioxide from the air, albeit indirectly. This is because everything we eat can be traced back to photosynthesis, the process by which plants take up carbon dioxide from the air and use it to produce the organic compounds needed for life. When we eat plants or animals that ate those plants, we ingest the carbon that the plants stored in their tissues. The carbon dioxide we exhale is the same carbon that was "inhaled" from the atmosphere by the plants we consume or by the animals that we eat.

However, when we burn fossil fuels, we release carbon dioxide formed from carbon atoms that were removed from the atmosphere millions of years ago by photosynthesis and sequestered in coal, petroleum, and natural gas. By burning these fossil fuels, we are increasing the current levels of carbon dioxide in the atmosphere, contributing to global warming.

While human respiration does release carbon dioxide, it is part of a closed-loop system where the carbon dioxide returns to the atmosphere, and the cycle begins again. The amount of carbon that enters the atmosphere from human breathing is roughly equal to the amount pulled out of the air by other natural processes, like plant growth. This natural ""fast carbon cycle" has been at work throughout Earth's history.

According to calculations, the global mass of CO2 produced by human exhalation is approximately 3.13 billion metric tons, with the global population estimated at 7.9 billion. This means that humans account for about 8.5% of total global emissions just by breathing. This percentage increased to about 9% during the COVID-19 pandemic in 2020 as total emissions declined due to various lockdown measures.

While human respiration does release a significant amount of carbon dioxide into the atmosphere, it is important to note that it is a natural part of the carbon cycle and does not contribute to global warming. The primary concern regarding global warming and climate change is the burning of fossil fuels, which releases carbon dioxide that has been sequestered for millions of years, disrupting the natural balance of carbon dioxide in the atmosphere.

Burning fossil fuels increases carbon dioxide levels

The carbon dioxide exhaled by humans does not contribute to global warming because humans also take up an equivalent amount of carbon dioxide from the air through the food they eat. This food can ultimately be traced back to photosynthesis, the process by which plants take up carbon dioxide from the air and use it to produce the organic compounds needed for life. Thus, the carbon dioxide humans exhale is part of a closed loop, and they are not disturbing the carbon dioxide content of the atmosphere by breathing.

However, burning fossil fuels does increase carbon dioxide levels in the atmosphere. Fossil fuels like coal, oil, and natural gas contain carbon from millions of years of photosynthesis, and when they are burned, this carbon is released back into the atmosphere. Since the middle of the 20th century, annual emissions of carbon dioxide from burning fossil fuels have increased every decade, from about 11 billion tons of carbon dioxide per year in the 1960s to an estimated 37.4 billion tons in 2024.

The burning of fossil fuels releases greenhouse gases such as carbon dioxide and nitrous oxide, which intensify the greenhouse effect and increase the Earth's average air temperatures. These gases can remain in the atmosphere for decades to hundreds of years. The effects of burning fossil fuels, especially carbon dioxide, are having far-reaching consequences on the climate and ecosystems. It is the primary cause of current climate change, altering the Earth's ecosystems and causing human and environmental health problems.

In addition to increasing carbon dioxide levels, burning fossil fuels also emits a range of pollutants that reduce air quality and harm life, such as sulfur dioxide, nitrogen oxides, and airborne particles like soot. These pollutants can cause respiratory diseases and increase the reflectivity of the atmosphere, leading to a slight cooling effect. They also contribute to the formation of acid rain, which can contaminate freshwater sources and harm wildlife.

To address the issue of increasing carbon dioxide levels and mitigate the impacts of climate change, a transition to renewable energy sources and improved energy efficiency is necessary. Reducing the burning of fossil fuels and transitioning to cleaner alternatives are crucial steps in this process.

Carbon dioxide amplifies the natural greenhouse effect

The carbon dioxide exhaled by humans does not contribute to global warming. This is because humans also take up an equivalent amount of carbon dioxide from the air, albeit indirectly. Everything we eat can be traced back to photosynthesis, the process by which plants take up carbon dioxide from the air and use it to produce the organic compounds needed for life. Our bodies can be regarded as "living engines" that require fuel and oxygen to produce the energy needed to sustain life. In that sense, we are not very different from a car. Both for us and for the car, the source of oxygen is the air, roughly 20% of which is made up of oxygen.

However, human activity has been warming the planet. By burning fossil fuels, we are releasing carbon dioxide that forms from carbon atoms that had been removed from the atmosphere millions of years ago by photosynthesis. This carbon dioxide is then sequestered in coal, petroleum, and natural gas, which form when plants and animals die and decay. By burning these fossil fuels, we are increasing the current levels of carbon dioxide in the atmosphere, amplifying the natural greenhouse effect.

The greenhouse effect is the process by which heat is trapped near Earth's surface by substances known as "greenhouse gases," such as carbon dioxide, methane, and nitrous oxide. These gases absorb heat radiating from the Earth's surface and re-release it in all directions, including back toward the Earth's surface. Without any carbon dioxide, Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, people are causing global temperatures to rise.

In the past 60 years, carbon dioxide in the atmosphere has increased 100-200 times faster than it did during the end of the last ice age. Carbon dioxide is Earth's most important long-lived greenhouse gas, and it has been determined that if carbon dioxide were removed, the terrestrial greenhouse effect would collapse, and Earth's surface temperature would drop significantly, by approximately 33°C (59°F).

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