What are greenhouse gases?

Skleníkové plyny sú plyny prítomné v atmosfére Zeme, ktoré absorbujú a emitujú infračervené žiarenie. Tento proces spôsobuje skleníkový efekt, ktorý vedie k otepleniu planéty. Tieto plyny umožňujú prenikaniu slnečného žiarenia na povrch Zeme, ale zadržiavajú teplo vyžarované späť do vesmíru, čím prispievajú k udržiavaniu teploty potrebnej pre život, no súčasný nadmerný nárast ich koncentrácií spôsobuje globálne otepľovanie a meniace sa klimatické podmienky.

1 – Water vapor or H2O

Yes, good old H2O, a formula familiar even to those who skipped physics class, is a major greenhouse gas. However, if water vapor contributes to a large extent to the natural greenhouse effect, it hardly outweighs the anthropogenic greenhouse effect that is related to human activity. Especially since the lifetime of water vapor in the atmosphere is only a few days.

2 – Carbon dioxide or CO2

When we talk about global warming, his name comes first. Is correct ! CO2 is public enemy number 1. Although it occurs naturally from the decomposition of animal and plant matter, its concentration has increased by more than 50 % since the beginning of the industrial era. Carbon dioxide alone is responsible for two-thirds of the human-caused greenhouse effect. 80 % of CO2 emissions of human origin come from fossil fuels (coal, oil, gas), which we use for heating, for movement, from the pre-chemical and steel industries... The remaining 20 % come from the destruction of forests. In addition, CO2 is a gas that decomposes very slowly: it remains in the atmosphere for approximately one hundred years.

3 – Methane (CH4)

It is the second most important greenhouse gas after carbon dioxide. And in recent years, it has reached record concentrations in the atmosphere. On a global scale, about 18 % contribute to warming. Methane emissions are half of natural origin (fermentation or rotting, wetlands, etc.), half of human origin: intensive cattle breeding, rice cultivation, landfilling of organic waste, oil and gas extraction, etc. This is one of the reasons why the reduction consumption of meat beneficial for the planet. This is also why environmental activists rebel against new projects for gas fields or liquefied natural gas. Even though methane decays faster in the atmosphere – 14 years on average – it has a GWP twenty-five times that of CO2!

4 – Nitrous oxide (N2O)

Another name for laughing gas. But it's no fun for the environment. Nitrous oxide is responsible for approximately 6% of global warming and is also involved in the destruction of the ozone layer. Its main human sources of emissions are agriculture (nitrogen fertilizers), biomass burning (cleaning by fire in tropical countries), industrial activities. With a lifetime of 121 years in the atmosphere, nitrous oxide has a GWP of 310.

5 – Ozone (o3)

A paradoxical gas. Unlike the others, ozone is an indirect greenhouse gas. It is actually formed by a photochemical process from precursor gases (methane, volatile organic compounds, etc.). Ozone has a protective effect in the stratosphere (upper atmosphere) by absorbing particularly harmful filtering UV-B rays, while in the lower atmosphere it contributes to global warming.

6 – Halogenated hydrocarbons and other artificial fluorinated gases (HFC, CFC, PFC, SF6)

Unlike other greenhouse gases, halogenated hydrocarbons do not exist naturally, except for carbon fluoride (CF4), which is used in the manufacture of semiconductors. However, they are the most powerful greenhouse gases, with most lifetimes of several hundreds or even thousands of years, making them particularly problematic.

Among them, SF6 or sulfur fluoride, used as an insulator in high-voltage technology, has a GWP of 22,800. Technical magnesium production and semiconductor manufacturing also produce large amounts of sulfur fluoride. Perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs) are used primarily in air conditioning systems, in the production of synthetic foams and electrical insulators, and in the production of aluminum and semiconductors.

Hydrochlorofluorocarbons (CFCs), which have contributed to increasing the greenhouse effect in depleting the ozone layer, have been very strictly controlled or even banned since the Montreal Protocol in 1987. Ironically, the replacements on the market (HFCs, PCFs and SF6) are potent greenhouse gases . Spring