The Major Greenhouse Gases and Their Sources

The greenhouse effect that was identified in 1896 is not entirely a bad thing. Greenhouse gases warm the earth’s surface by absorbing heat from the sun and not letting it return to space. This heat absorption is widely known as the greenhouse effect. The greenhouse effect is needed to keep the planet warm and habitable. It protects the earth from being frozen and uninhabitable like Mars.

But over the last one and half-century, due to human activities, greenhouse gases have increased a lot in our planet’s atmosphere. The excessive burning of fossil fuels has artificially excited the natural greenhouse effect. It has negatively impacted the climate of our planet. As a result, every living creature on earth is now facing severe consequences of global warming.

Sunlight makes the earth warm and habitable. As we know, nearly 30 percent of the solar energy that comes to our planet returns to space. Only 70% of the solar energy passes through the atmosphere and is absorbed by the earth’s surface. Then the heat radiates back up as infrared light. While going back to space, almost 90 percent of the infrared light gets absorbed by greenhouse gases and again directs back towards the planet, causing further warming.

For the past 800,000 years, there were almost 200 to 280 molecules of Greenhouse gases per one million molecules of air. Nowadays, the concentration of major greenhouse gases has become much higher, nearly 400 molecules per one million molecules of air. Extra heat is being absorbed in the atmosphere, and the result is global warming.

The greenhouse gases that are the major causes of global warming are water vapor, carbon dioxide, nitrous oxide, methane, and synthetic fluorinated gases.

Water Vapor:

Water vapor is the most abundant of all greenhouse gases. According to NCDC (National Climatic Data Center), changes in the atmospheric concentrations of water vapor are not directly connected to human activities. Still, it is linked to global warming due to the other greenhouse gases that humans emit.

When the air becomes warm, it holds more water. As a result of an increase in the temperature of the atmosphere, more water is vaporized from the earth’s surface. It induces more significant warming and perpetuates ‘a positive feedback loop’. However, climate scientists are not sure about the impact of this ‘positive feedback loop’ because more water vapor increases cloud cover that can reflect the sun’s incoming radiation away from the planet.

Carbon Dioxide:

Carbon dioxide is considered ‘the most important among the greenhouse gases. We all know that with each exhalation, every human being emits this gas. But excess carbon dioxide gas is mainly produced from burning fossil fuels such as oil, coal, and other natural gases. These fossil fuels are used to power machines and vehicles and generate electricity.

Though compared with other greenhouse gases, it is less effective to trap heat in the atmosphere. Carbon dioxide creates a significant impact on our planet’s climate as it is the most abundant and most prevalent among all greenhouse gases. Carbon dioxide accounts for nearly 80 percent of the major greenhouse gases.

Trees help in removing carbon dioxide from the atmosphere. Due to deforestation, carbon dioxide is increasing a lot in the atmosphere. Organisms in the ocean also remove carbon dioxide by converting the gas into calcium carbonate. But this process of rock-forming is prolonged. Overall, carbon dioxide gas lingers in the atmosphere for many years. According to Stephen Montzka, “even if we stopped emitting carbon dioxide today, we would still see warming from that for a very long time.”

Methane:

Methane is a hydrocarbon gas produced not only from natural causes but also from human activities like agriculture and farming, landfills, coal mining, wastewater treatment, oil and gas industry, mobile and stationary combustions, and other industrial processes. Countries like China, the United States, Mexico, Indonesia, Russia, Brazil, India, Nigeria are responsible for half of the methane emissions in the world.

Though it accounts for nearly 10-20 percent of the major greenhouse gases and has a shorter lifespan than CO2, methane is one of the most potent greenhouse gases to absorb the sun’s radiation. It is many times more potent than carbon dioxide to absorb heat in the air. This colorless and odorless gas causes almost 25 percent of today’s global warming.

Nitrous Oxide:

Nitrous oxide, widely known as the ‘laughing gas, is a growing climate threat in today’s world. After carbon dioxide and methane, nitrous oxide is the most significant greenhouse gas. The gas is rapidly increasing in our planet’s atmosphere due to anthropogenic activities like large-scale farming, cattle ranching, and farming with synthetic fertilizers. Nitrous oxide stays in the atmosphere for a long time. Like methane, nitrous oxide has more efficiency than carbon dioxide to trap the heat in the earth’s air.

According to a report, one pound of nitrous oxide can warm the atmosphere of the planet nearly 300 times more than one pound of carbon does over one hundred years. Nitrous oxide emissions are fast increasing in emerging economies such as Brazil, India, and China. Burning fossil fuels contribute nearly one-seventh of nitrous oxide emissions. The emission of nitrous oxide exceeds the predicted levels because most countries in the world have no policy to reduce it.

Fluorinated Greenhouse Gases:

Fluorinated gases are produced only from human-related activities; there are no natural sources of these gases. Fluorinated gases are often called the “high global warming potential (GWP) gases.” Three leading potent fluorinated greenhouse gases contribute to global warming: hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).

The most significant sources of fluorinated gases are heat pumps, air conditioners, stationary refrigerators, electrical transmission equipment, etc. Challenging fluorinated gases emit in smaller quantities compared to other greenhouse gases. They are the most potent and have the most extended lifespans (1 year to 50,000 years). After emission, these gases are widely dispersed all over the world. Only a high level of sunlight can destroy these harmful gases in the upper portion of the atmosphere.

Closure

To limit environmental crisis and global warming, it is needed to reduce greenhouse gas emissions. We should use less electricity. Usage of renewable energy, traveling by bicycles and electric cars, planting more trees, carbon emission reduction technologies, etc., are intelligent ways to reduce the severity of the consequences of greenhouse gas emissions.