Greenhouse Gases
- Greenhouse Gases and the Greenhouse Effect
Greenhouse gases (also known as GHGs) are heat-trapping gases in the Earth's atmosphere.
During the day, sunlight travels through the atmosphere, warming the Earth's surface. At night, the Earth's surface cools, releasing heat back into the air. But some of the heat is trapped by greenhouse gases in the atmosphere. That's why the Earth's average temperature remains at 14°C (57°F).
These gases act like the glass walls of a greenhouse—hence the name greenhouse gases. Without this greenhouse effect, temperatures would drop to -18°C (-0.4°F); too cold to support life on Earth.
But human activities are changing the Earth's natural greenhouse effect, and emissions of greenhouse gases have increased dramatically. Scientists agree that greenhouse gases are responsible for global warming and climate change.
Since the Industrial Revolution, humans have emitted large amounts of greenhouse gases into the atmosphere. This number has increased dramatically over the past century as global warming has knock-on effects. Global temperatures have accelerated over the past 30 years and are now at their highest level on record.
- What are the Main Greenhouse Gases?
- Carbon dioxide (CO2): Carbon dioxide is released through natural processes such as volcanic eruptions, plant respiration, and animal and human respiration. But since the beginning of the Industrial Revolution in the 1800s, the concentration of carbon dioxide in the atmosphere has increased by 50 percent due to human activities such as the burning of fossil fuels and massive deforestation. Due to its abundance, carbon dioxide is a major contributor to climate change.
- Methane: Methane occurs naturally through decomposition. But human activities once again broke the natural balance. Cattle farming, landfills, rice farming, and traditional oil and gas production release large amounts of methane.
- Nitrous Oxides (NOx): Nitrous oxide is produced through the large-scale use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass combustion.
- Water vapor: Water vapor is the most abundant greenhouse gas. As Earth's atmosphere warms, water vapor increases, but unlike carbon dioxide, which can remain in Earth's atmosphere for centuries, water vapor persists for days.
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