When discussing global warming and the climate crisis, CO2 is the first gas that comes to mind. In reality, it is just one of several greenhouse gases contributing to the warming of the Earth.
Carbon dioxide (CO2) accounts for approximately 70% of global greenhouse gas emissions, while the remaining emissions come from methane (CH4), nitrous oxide (N2O), and fluorinated gases (F-gases).
Methane
Methane is the second most potent greenhouse gas contributing to global warming after carbon dioxide.
About 40% of methane is produced from natural sources, primarily wetlands, while 60% is generated from human activities such as agriculture (livestock farming and rice cultivation), fossil fuel extraction, and waste management.
The global warming potential (GWP) of CH4 is, on average, 28 times greater than that of CO2, but its atmospheric lifetime is shorter. Therefore, it is a significant focus in short-term efforts to mitigate global warming.
Researcher Mathijs Harmsen from the Netherlands Environmental Assessment Agency states that reducing CH4 emissions is very effective for cooling the Earth in the short term, as methane concentrations in the atmosphere will rapidly decrease.
However, despite global commitments to reduce greenhouse gas emissions signed by many countries, including the United States and the European Union, the situation remains grim.
In a research report from the Global Carbon Project, scientists noted that CH4 is increasing faster than other greenhouse gases and is currently at 2.6 times the levels seen during the pre-industrial period.
Currently, greenhouse gas emissions are primarily caused by human activities, with the largest share coming from fossil fuel use (Photo: Getty).
Nitrous Oxide
The global warming potential of N2O is nearly 300 times greater than that of CO2.
N2O emissions primarily arise from synthetic nitrogen fertilizers and manure used in agriculture. Other sources include human activities (chemical industry, wastewater, fossil fuel use) and natural sources (soils and oceans).
The key to addressing this issue is to use fertilizers more efficiently. The potential for reducing climate change related to N2O emissions could improve by two-thirds if we reduce fertilizer use by over 20% on global arable land, especially in subtropical agricultural regions.
Fluorinated Gases
F-gases include: PFCs, HFCs, CFCs, and SF6, which are used in cooling (refrigerators and freezers), heat pumps, air conditioning, and electrical grids.
Although the volume used is relatively small, these gases have an extraordinarily strong greenhouse effect. For example, SF6, used in electrical substations, is 24,000 times more harmful than CO2 over a 100-year period.
In 1987, 195 countries ratified the Montreal Protocol with the primary goal of significantly reducing CFCs in the atmosphere.
In 2016, the Kigali Agreement aimed to eliminate the use of HFCs. Most recently, in 2023, the European Union signed a treaty to gradually ban the sale of equipment containing F-gases, with a view to completely phasing out these products by 2050.
