Though carbon dioxide is the most well-known and second most abundant greenhouse gas, it’s only one piece of the climate change puzzle. While sunlight reaches Earth, the planet absorbs some of this energy and reflects it back as infrared waves, which we experience as heat. These waves normally escape into space, but certain gases in the atmosphere, known as greenhouse gases, trap this infrared energy, preventing it from escaping. This is the greenhouse effect, essential for maintaining life on Earth, but an excess of these gases leads to global warming.
While carbon dioxide is the primary culprit due to its abundance, amplified by fossil fuel burning, other gases have significantly higher heat-trapping potential, known as Global Warming Potential (GWP), compared to CO2.
Methane
, for instance, has a GWP of 30, meaning it traps 30 times more heat than carbon dioxide. Around 60% of methane emissions result from human activities, primarily agriculture, fossil fuels, and waste decomposition. While efforts are underway to reduce methane emissions from the energy sector, full implementation of current pledges would only cut emissions from oil and gas by 20% by 2030.
Nitrous oxide (N2O)
, another potent greenhouse gas, has a GWP of 265. While naturally present in the atmosphere, around 40% of N2O emissions are human-driven, primarily from agricultural soil management, including the use of fertilizers. Efforts to limit this gas in the EU have faced opposition from farmers, highlighting the complex challenges of climate action.
Fluorinated gases (F-gases)
, man-made substances containing fluorine, have GWPs ranging from thousands to tens of thousands, trapping significantly more heat than CO2. These gases are widely used in refrigeration, heat pumps, fire protection, insulation, and aerosols. While initially developed as replacements for ozone-depleting substances, their high GWP makes them a significant concern. They are categorized into four main groups:*
Hydrofluorocarbons (HFCs):
The largest subset of F-gases, used in refrigeration, insulation, and air conditioning, with a GWP thousands of times greater than CO2.*
Perfluorocarbons (PFCs):
A byproduct of aluminum manufacturing and used in electronics, with a GWP nearly 10,000 times that of CO2.*
Sulfur hexafluoride (SF6):
Used to insulate power lines, with a GWP of 23,500, making it the most potent greenhouse gas evaluated by the Intergovernmental Panel on Climate Change.*
Nitrogen trifluoride (NF3):
Used in electronics manufacturing, with a GWP of 17,200, contributing to its growing atmospheric concentration due to the booming electronics market.Finally, while
water vapor
is the most abundant greenhouse gas, it does not directly cause global warming. It plays a critical role in the natural cycle, trapping heat and contributing to a liveable climate. However, as temperatures rise due to other greenhouse gases, water vapor acts as a feedback loop, amplifying the warming effects. Higher temperatures lead to increased evaporation and water vapor in the atmosphere, further contributing to warming.Understanding the multifaceted nature of greenhouse gases is crucial for addressing climate change. While CO2 receives the most attention, these other gases, often overlooked, are playing a significant role in global warming. Effective climate action requires a comprehensive approach that addresses all greenhouse gas emissions, not just carbon dioxide.
