Carbon dioxide (CO2) is one of many greenhouse gases. Learn about the impact of global warming, its origins and its contribution to the EU’s emissions, which aims to drastically reduce greenhouse gases that cause climate change.
Carbon dioxide (CO2) is the best known, but other substances present in smaller quantities in the atmosphere can contribute more to global warming.
What do greenhouses gases do?
Greenhouse gases act similarly to the glass in a greenhouse: they absorb the sun’s heat that radiates from the Earth’s surface, trap it in the atmosphere and prevent it from escaping into space. The greenhouse effect keeps the Earth’s temperature warmer than it would otherwise be, supporting life on Earth.
Many greenhouse gases occur naturally in the atmosphere, but human activity contributes to their accumulation. As a result, the greenhouse effect in the atmosphere is boosted and it alters our planet’s climate, leading to shifts in snow and rainfall patterns, a rise in average temperatures and more extreme climate events such as heatwaves and floods.
Which greenhouse gases are there?
There are different types of greenhouse gases and their global warming potential varies.
Naturally occurring gases in the atmosphere – but also generated through human activities – include among others carbon dioxide, methane (CH4), and nitrous Oxide (N2O).
Fluorinated greenhouse gases (F-gases) are man-made gases used in industry and they have a high global warming potential, often several thousand times stronger than CO2. They include Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), Sulphur hexafluoride (SF6), and Nitrogen trifluoride (NF3).
F-gases are often used as substitutes for ozone-depleting substances – human-made chemicals that, once emitted, reach the upper atmosphere and destroy the protective ozone layer. Unlike ozone-depleting substances, F-gases do not damage the atmospheric ozone layer.
The following seven types of greenhouse gases are covered by the Kyoto Protocol and the Paris Agreement, which aim to coordinate the global response to climate change:
CO2 is naturally produced by animals during respiration and through the decay of biomass. It also enters the atmosphere through burning fossil fuels and chemical reactions. It is removed from the atmosphere by plants in the process known as photosynthesis that turns sunlight into energy. That is why forests have an important role in capturing carbon.
Methane is a colourless gas, which is the main constituent of natural gas. Its emissions result from the production and transport of coal, natural gas and oil, as well as from livestock and other agricultural practices, land use and by the decay of organic waste in municipal solid waste landfills. In 2021, most methane emissions came from agriculture, forestry and fishing.
This gas is mainly produced as a result of microbial action in the soil, the use of fertilisers containing nitrogen, the burning of timber and in chemical production. It is emitted in agricultural and industrial activities as well as in land use; the combustion of fossil fuels and solid waste; and the treatment of wastewater. In the EU, agriculture, forestry and fishing were the sectors that emitted more nitrous oxide in 2021.
Hydrofluorocarbons represent about 90% of the fluorinated gas emissions and the EU is working to phase them out by 2050.
They are mainly used to absorb heat in refrigerators, freezers, air conditioners and heat pumps; as propellants in asthma sprays and technical aerosol spray cans; as blowing agents for foams and in fire extinguishers. In 2021, they prevailed in the wholesale and retail trade, repair of motor vehicles and motorcycles sectors.
Perfluorocarbons are man-made compounds commonly used in industrial manufacturing processes.
Sulphur hexafluoride is commonly used in the insulation of power lines.
Nitrogen trifluoride is used as a chamber-cleaning gas in production processes to clean unwanted build-ups on microprocessor and circuit parts as they are being constructed.
Greenhouse gases and their global warming impact
As greenhouse gases have different global warming potential, their impact is typically converted into a CO2 equivalent to make comparisons meaningful.
In 2021, greenhouse gas emissions generated by EU economic activities stood at 3.6 billion tonnes of CO2 equivalent, 22 % lower than in 2008.
CO2 represented almost 80% of the volume of all greenhouse gases emissions in the EU in 2021, followed by methane with more than 12%.
Methane doesn’t stay in the atmosphere as long as CO2 – but it absorbs much more sun energy, is a dangerous air pollutant and its leaks can provoke explosion.
Together, all F-gases only account for approximately 2.5% of the EU’s greenhouse gas emissions. However, even if emitted in smaller quantities, they trap heat far more effectively than CO2.
How does the EU plan to reduce greenhouse gases?
The EU Climate Law sets legally binding targets for reducing greenhouse gas emissions: they should be down 55% by 2030 compared to 1990 levels and the EU should reach net zero emissions by 2050.
To reach these goals, the EU is taking a wide range of measures:
- cutting emissions in transport
- setting rules to save energy and invest in renewables
- preventing the relocation of greenhouse gas emitting industries outside the EU in a bid to avoid tighter standards
- boosting the world’s first major carbon market – the European Emissions Trading System
- setting reduction targets for each EU country
- boosting forests and other carbon capturing areas