What are the main greenhouse gases
Pro Research Analysisby 
Searched over 200M research papers
Main Greenhouse Gases: Key Contributors to Climate Change
Introduction to Greenhouse Gases
Greenhouse gases (GHGs) are atmospheric gases that absorb and emit infrared radiation, leading to the greenhouse effect, which warms the Earth's surface. The primary greenhouse gases include water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3) .
Water Vapor: The Dominant Greenhouse Gas
Water vapor is the most abundant greenhouse gas in the atmosphere, contributing significantly to the greenhouse effect. It accounts for approximately 85-90% of the greenhouse effect due to its ability to absorb and emit infrared radiation across a wide range of wavelengths . Unlike other greenhouse gases, water vapor levels are not directly influenced by human activities but are instead controlled by natural processes such as evaporation and condensation.
Carbon Dioxide (CO2): The Key Anthropogenic Greenhouse Gas
Carbon dioxide is a critical greenhouse gas, primarily produced by the burning of fossil fuels, deforestation, and various industrial processes. Although it constitutes a small fraction of the atmosphere (about 0.040%), its concentration has significantly increased due to human activities, contributing around 72% of the enhanced greenhouse effect . The current atmospheric CO2 levels have consistently exceeded 400 ppm, the highest in recorded history.
Methane (CH4): A Potent Greenhouse Gas
Methane is another significant greenhouse gas, with a much higher heat-trapping capability per molecule than CO2. It is released from natural sources such as wetlands and anthropogenic sources including agriculture (especially livestock), landfills, and fossil fuel extraction. Methane contributes about 21% to the enhanced greenhouse effect .
Nitrous Oxide (N2O): A Powerful Greenhouse Gas
Nitrous oxide, though present in smaller quantities, is a potent greenhouse gas with a global warming potential significantly higher than CO2. It is mainly emitted from agricultural activities, fossil fuel combustion, and industrial processes. N2O contributes approximately 7% to the enhanced greenhouse effect .
Ozone (O3): A Dual Role in the Atmosphere
Ozone plays a dual role in the atmosphere. In the stratosphere, it forms the ozone layer, which protects life on Earth by blocking harmful ultraviolet radiation. However, in the troposphere, it acts as a greenhouse gas, contributing to warming. Ozone is formed by photochemical reactions involving pollutants from vehicle emissions and industrial activities .
Conclusion
The main greenhouse gases—water vapor, carbon dioxide, methane, nitrous oxide, and ozone—play crucial roles in regulating the Earth's climate. While water vapor is the most abundant and naturally occurring greenhouse gas, CO2, CH4, and N2O are significantly influenced by human activities and are major contributors to the enhanced greenhouse effect and global warming. Understanding and mitigating the emissions of these gases is essential for addressing climate change.
Sources and full results
Most relevant research papers on this topic