Final answer:
Methane (CH4) and carbon dioxide (CO2) both contribute to the greenhouse effect, with methane having a higher global warming potential but a shorter atmospheric lifespan than CO2. Both gases are released through human activities such as burning fossil fuels and livestock farming, and adversely affect the global climate.
Step-by-step explanation:
Methane (CH4) and carbon dioxide (CO2) are both significant atmospheric pollutants that contribute to the greenhouse effect. However, they differ in their global warming potential (GWP), with methane being approximately 28 times more effective than carbon dioxide at absorbing infrared radiation over a 100-year period. Despite methane's potency, it does not last as long in the atmosphere as CO2. Burning fossil fuels is a major source of CO2, while methane is released from activities such as livestock farming and decomposing organic matter in landfills. The presence of these gases in the atmosphere is a global issue because their effects are not contained by national borders and can lead to worldwide climate changes.