The Other Greenhouse Gases Warming the Planet

AFP/APP

Paris: While carbon dioxide (CO2) is widely recognized as the primary greenhouse gas, others, such as methane and nitrous oxide, are significantly impacting global warming and climate change.

Methane

CO2 contributes to approximately two-thirds of the warming attributed to greenhouse gases. Methane (CH4) ranks as the second most important greenhouse gas tied to human activity.

About 40 percent of methane emissions originate from natural sources, particularly wetlands, while the majority (60 percent) is linked to human activities such as agriculture, fossil fuels, and waste management.

Methane is over 80 times more potent than CO2 over a 20-year period but has a shorter atmospheric lifespan, making it a crucial target for short-term climate mitigation efforts.

Mathijs Harmsen, a researcher at the Netherlands Environmental Assessment Agency PBL, notes that reducing methane emissions could provide a substantial short-term cooling effect.

However, despite global commitments to cut greenhouse gas emissions, methane levels continue to rise rapidly, now standing 2.6 times higher than pre-industrial levels.

Nitrous Oxide

Nitrous oxide (N2O) is the third major greenhouse gas, nearly 300 times more potent than CO2. Its emissions mainly stem from synthetic nitrogen fertilizers and manure used in agriculture.

Other emissions arise from human activities, including the chemical industry and fossil fuel combustion, as well as natural sources like soil and oceans. Research indicates that human-induced nitrous oxide emissions have increased by 30 percent over the past four decades, with efficient fertilizer use being a key solution for mitigation.

Fluorinated Gases

Fluorinated greenhouse gases, such as perfluorocarbons (PFCs), hydrofluorocarbons (HFCs), and sulfur hexafluoride (SF6), are found in various appliances, including refrigerators and air conditioners.

Despite their lower concentrations, these gases have an extremely high warming potential. For instance, SF6 has a greenhouse effect 24,000 times greater than CO2 over a century.

International agreements, such as the Montreal Protocol and the Kigali Amendment, have aimed to phase out harmful fluorinated gases. Last year, the EU reached an agreement to progressively ban the sale of equipment containing these gases, particularly HFCs, with the goal of complete elimination by 2050.