Gases produced by landfills are primarily comprised of methane and carbon dioxide.

Methane:
- Methane (CH4) is a potent greenhouse gas that is produced during the decomposition of organic waste in landfills.
- It is formed as a result of anaerobic (oxygen-free) decomposition of organic matter by microorganisms, such as bacteria and archaea, in the absence of oxygen.
- Methane is a flammable gas and can be released into the atmosphere if not properly managed.
- It has a global warming potential (GWP) that is significantly higher than carbon dioxide, meaning it has a greater ability to trap heat in the atmosphere and contribute to climate change.

Carbon Dioxide:
- Carbon dioxide (CO2) is also emitted during the decomposition process in landfills.
- It is produced from the oxidation of carbon-containing materials and the combustion of organic matter.
- Carbon dioxide is a well-known greenhouse gas and is the primary driver of climate change.
- It has a lower GWP compared to methane but is still a significant contributor to global warming.
- Landfills are a major source of carbon dioxide emissions, as they release large amounts of this gas during the decomposition of organic waste.

Other Gases:
- While methane and carbon dioxide are the main gases produced in landfills, there are also smaller amounts of other gases that can be emitted.
- These gases may include trace amounts of volatile organic compounds (VOCs), nitrogen oxides (NOx), sulfur compounds (such as hydrogen sulfide), and trace amounts of other greenhouse gases like nitrous oxide (N2O).
- The composition and concentration of these other gases can vary depending on factors such as waste characteristics, landfill management practices, and environmental conditions.

Conclusion:
In conclusion, the gases produced by landfills are primarily composed of methane and carbon dioxide. Methane is a potent greenhouse gas with a high GWP, while carbon dioxide is a well-known greenhouse gas that is the primary driver of climate change. Proper landfill management practices, such as gas collection and flaring or utilization, are important to minimize the release of these gases into the atmosphere and reduce their impact on climate change.