We explain what carbon dioxide is and why it is so important. Carbon cycle. CO2 and climate change. Uses of CO2.
What is carbon dioxide?
When talking about carbon dioxide, carbon dioxide or CO2 (from its chemical formula: CO 2 ), it refers to a colorless and water-soluble gas , whose molecules are composed of a carbon atom and two of oxygen, joined by covalent double bonds.
CO2 is an extremely abundant gas on Earth, essential for life as we know it and present in numerous organic compounds, including hydrocarbons (natural gas, oil , etc.) or the air that aerobic living beings exhale (or be that we breathe). The biological importance of CO 2 lies in the fact that plants need it to carry out photosynthesis , as well as certain types of cyanobacteria for their energy production processes.
In the presence of a constant pressure, carbon dioxide is a gas, but it can also be forced to become a liquid by increasing the pressure (through the liquefaction process ) or even a solid, forming the so-called “dry ice” or carbonic snow .
The greatest concentration of this gas on the planet is, however, in the atmosphere , dissolved among many other gases that make up the air . It is produced daily as a byproduct of natural processes, such as respiration , the decomposition of organic matter or its combustion (for example, in forest fires) and in the fermentation of sugars. It is also generated artificially, through the burning of fossil fuels.
CO2 can also be found outside our planet: the atmospheres of Venus and Mars have demonstrated an abundant presence of this gas , which makes up 95% of them.
In principle, carbon dioxide is an extremely useful substance for man, who has been able to use the following uses:
- In the food industry, beverages (soft drinks) are injected to give effervescence.
- It is part of the compounds present in fire extinguishers, since CO 2 is not combustible.
- It is frequently used as a refrigerant (in gas or as ice) and in the creation of special effects, such as artificial fog.
- It is part of the gases used to form lasers.
- In medicine, it is used as a contrast agent or as a gas for insufflation in laparoscopy, as well as in aesthetic treatments.
CO 2 on our planet is part of a biogeochemical cycle that exchanges carbon between the layers of the atmosphere, the water of the seas and the deposits on the mainland . This allows carbon atoms to be reused and life is sustainable on the planet.
Thus, the carbon present in methane (CH 4 ) and atmospheric CO 2 passes through photosynthesis to plants, and also to water when diluted in raindrops and going to the ocean , where it forms small amounts of carbonic acid. There involved breathing cycles and microbial decomposition, releasing new CO 2 in gaseous form into the atmosphere.
CO2 and climate change
Despite being naturally present in the atmosphere, carbon dioxide is, together with other compounds, a greenhouse gas. This means that it contributes to forming a gaseous layer in the atmosphere that prevents heat radiation and increases the temperature of the planetary surface , which leads to gradual climatic changes whose effects we suffer from living beings.
Everything indicates that the increase in CO 2 levels in the atmosphere, a product of human industrial activity sustained since the seventeenth century (burning of hydrocarbons, metallurgy, mass fermentation, concrete manufacturing, etc.), would have markedly unbalanced the cycle. of carbon, accumulating much more of this gas in the atmosphere than it is possible to get rid of naturally. To get an idea, atmospheric CO 2 in 1750 was 0.028% , and at the beginning of the 21st century it is 0.037%.
This increase in gas also slowly increases the planet’s temperature by a few degrees, and that, although it may not seem so, has catastrophic effects on the climate by altering the delicate balance of the water cycle , sea currents and heat distribution. This has consequences as serious as the creation of new deserts ; the melting of the poles and perennial snows, thus increasing the level of the oceans; torrential floods and rains that ruin cities and crops, and cause land displacements ; and even more extreme weather stations: colder winters and more intense summers .
As if that were not enough, the increase in atmospheric CO 2 affects the present in the oceans, producing more carbonic acid and changing the pH of the seas, which gradually become more acidic and less suitable for life.
All these processes and consequences are known as climate change and there is currently a debate about what measures to take to stop, prevent and even reverse it , which requires a joint effort of the entire international community.