What is carbon dioxide? Concept, Uses, Cycle and Climate Change

Carbon dioxide

We explain what carbon dioxide is and why it’s so important. Carbon cycle. CO2 and climate change. Uses of CO2.

carbon dioxide

Normal levels of CO2 in the atmosphere are increased by industrial activity.

What is carbon dioxide?

When we speak of carbon dioxide, carbon dioxide or CO2 (from its chemical formula: CO2), we refer to a colorless gas soluble in water, whose molecules are composed of a carbon atom and two oxygen atoms, joined by covalent double bonds.

CO2 is an extremely abundant gas on Earth, indispensable for life as we know it and present in many organic compounds, including hydrocarbons (natural gas, oil, etc.) or the air we breathe out as aerobic living beings (that is, we breathe).

The biological importance of CO2 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 so-called “dry ice” or carbonic snow.

The highest 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 by-product of natural processes such as respiration, decomposition of organic matter or combustion of organic matter (e.g. in forest fires) and 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 the abundant presence of this gas, which makes up 95% of them.

 Uses of CO2

In principle, carbon dioxide is an extremely useful substance for man, who has been able to give it the following uses:

  • In the food industry, beverages (soft drinks) are injected to give effervescence.
  • It forms part of the compounds present in extinguishers, as CO2 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 laser beams.
  • In medicine, it is used as a contrast agent or as a gas for insufflation in laparoscopies, as well as in cosmetic treatments.

Carbon cycle

CO2 on our planet is part of a biogeochemical cycle that exchanges carbon between the layers of the atmosphere, seawater and land-based deposits. This allows carbon atoms to be reused and life to be sustainable on the planet.

Thus, the carbon present in methane (CH4) and atmospheric CO2 passes through photosynthesis to plants, and also to water by diluting into raindrops and going into the ocean, where it forms small amounts of carbonic acid.

This is where the cycles of respiration and microbial decomposition intervene, releasing new CO2 into the atmosphere in gaseous form.

 CO2 and climate change

Climate change is causing melting at the poles.

Although naturally present in the atmosphere, carbon dioxide is, along with other compounds, a greenhouse gas.

This means that it contributes to the formation of 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 living beings suffer.

Everything points to the fact that the increase in CO2 levels in the atmosphere, the product of sustained human industrial activity since the 17th century (burning of hydrocarbons, metallurgy, massive fermentation, manufacture of concrete, etc.), would have notoriously unbalanced the carbon cycle, accumulating much more of this gas in the atmosphere than it is possible to get rid of naturally.

To give you an idea, atmospheric CO2 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 temperature of the planet 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, marine currents and heat distribution.

This has consequences as serious as the creation of new deserts; the melting of the poles and perennial snows, thus raising the level of the oceans; floods and torrential rains that ruin cities and crops and cause land shifts; and even more extreme climatic seasons: more icy winters and more intense summers.

As if that were not enough, the increase in atmospheric CO2 affects the present in the oceans, producing more carbonic acid and modifying the pH of the seas, which gradually become more acidic and less fit for life.

All of these processes and consequences are known as climate change and there is currently a whole debate about what measures to take to halt, prevent and even reverse it, which requires a joint effort by the entire international community.

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