Where do greenhouse gases come from?
Everywhere.
The number of processes that produce greenhouse gases is nearly endless. While natural processes tend to balance themselves within their own cycles, this balance is missing in human-driven processes: although they support our way of life, they place a significant burden on the environment.
CARBON DIOXIDE CO₂
CO₂e = 1
CO₂ has a moderate warming effect. However, since it remains in the atmosphere for up to a million years, it influences the climate for a very long time.
- gas exchange at water surfaces (oceans, rivers and lakes)
- wildfires
- respiration (natural vegetation, wildlife, humans)
- decomposition processes
- volcanic eruptions
- combustion of organic materials (e.g. coal, oil, gas, wood) for energy and electricity production used in transportation, industry, housing, heating, construction, and the operation of the digital world (incl. artificial intelligence, web browsing, streaming, cryptocurrency), etc.
- waste incineration for energy production
- waste management in landfills
- land use changes (slash-and-burn, gas release from soil cultivation such as tillage, deforestation, draining of wetlands, urban development)
- fires
- respiration (livestock, crop plants)
METHANE CH₄
- bacterial decomposition processes in oceans, swamps and other wetlands
- gas release from thawing permafrost
- dissolution of methane hydrate deposits on the ocean floor and in polar coastal regions
- digestive processes in ruminant animals in livestock farming
- soil cultivation in agriculture
- bacterial decomposition processes in agriculture (e.g., rice paddies)
- storage and application of fertilisers in agriculture and forestry (e.g., manure, farm slurry)
- natural gas and oil production, coal mining
- bacterial decomposition processes in landfills, cesspits and sewage treatment plants
CO₂e = 28
Methane warms Earth 28 times more than CO₂, but only remains in the atmosphere for about 9 years. However, it causes significant damage during this short period. A CO₂e of 28 means that 1 ton of methane has the same warming effect over a 100-year period as 28 tons of CO₂.
NITROUS OXIDE N₂O (LAUGHING GAS)
CO2e = 273
Nitrous oxide is 273 times more potent than CO₂ and remains in the atmosphere for about 100 years.
- bacterial decomposition processes in oxygen-poor environments (e.g., in ocean areas with high plankton concentrations and in soils)
- bacterial decomposition of agricultural nitrogen fertilisers
- combustion of biomass and fossil fuels
FLUORINATED GASES (F-GASES)
NO NATURAL OCCURRENCE
HUMAN-EMITTED- tetrafluoromethane (CF₄): refrigerant in cooling systems, production of aluminium and electronic devices
- hydrofluorocarbons (e.g., CHF₃): refrigerants in cooling systems, blowing agents in foam materials, propellants for aerosol sprays
- nitrogen trifluoride (NF₃): production of solar cells, LC displays and semiconductors
- sulphur hexafluoride (SF₆): protective gas for technical processes, insulation for electric power plants, gas for car tires (tire gas)
CO₂e = 25 000
Although F-gases only occur in relatively small amounts, they have an extremely powerful warming effect (up to 25 000 times greater than CO₂) and can persist in the atmosphere for thousands of years. With emissions steadily rising and no natural processes to remove them from the atmosphere, they continuously warm the climate.
CO₂ EQUIVALENTS (CO₂e)
Various greenhouse gases contribute to climate change in different ways, as they retain heat in the atmosphere to different degrees and remain in the atmosphere for different lengths of time. To make their effects comparable and to better understand their overall contribution to global warming, they are converted into a common unit, the CO₂ equivalent (CO₂e). CO₂e indicate how much stronger a greenhouse gas is compared to the same amount of CO₂ over a period of 100 years, or how much CO₂ would be needed to achieve the same warming effect.