Carbon dioxide CO2

Carbon dioxide has become synonymous with the environmental friendliness of car transport. In recent years, however, CO2 has only been given a negative label. At the same time, it is a non-toxic, inert, colourless, tasteless and odourless gas. CO2 is a normal part of our lives. It is formed by the reaction of carbon with oxygen, for example in a process called combustion, but also in ordinary human breathing … what do you know about it?

First, let’s go back to 1975, when motorists celebrated victory over poisonous carbon monoxide (CO), which was commonly released during fuel combustion. Thanks to the invention and mass deployment of a catalytic converter, this dangerous substance was successfully eliminated. The automotive catalytic converter reduces emissions of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). In simple terms, the catalytic converter transforms harmful emissions into less harmful substances such as carbon dioxide (CO2), water (H2O), and nitrogen (N2).

Over time, however, it became apparent that even inert carbon dioxide (CO2) can be a problem, as it is considered one of the main causes of the greenhouse effect and global warming. CO2 is a greenhouse gas that traps heat in the atmosphere and affects the Earth’s climate.

CO2 - carbon dioxide - illustrative image

Today, carbon dioxide (CO2) has become primarily a political issue and is discussed in various contexts. Car manufacturers are now fined for CO2 emissions produced by the vehicles they manufacture. Carbon dioxide is often confused with the general term exhaust gas emissions, which is not entirely correct. As mentioned in the previous paragraph, exhaust gas emissions consist of many components, and carbon dioxide is just one of them!

What do you know about carbon dioxide (CO2)? How do you perceive this gas? Let’s take a look at a few basic questions and answers in broader contexts.

What Exactly is CO2 and Does Breathing it Harm Health?

The molecule of carbon dioxide is composed of two oxygen atoms and one carbon atom. This compound is heavier than air because the molar mass of carbon dioxide is 44 g/mol (molar mass of air is 28.96 g/mol), so it stays close to the ground. It is an inert, colorless gas, without taste or odor. CO2 is not toxic unlike CO (carbon monoxide). Carbon dioxide (CO2) is a non-toxic gas, but it can be harmful to humans at high concentrations. Inhaling higher concentrations of CO2 can lead to difficulty breathing, dizziness, nausea, and even loss of consciousness. This phenomenon occurs, for example, in poorly ventilated enclosed spaces. CO2 is produced not only during the combustion of hydrocarbon fuels but also during normal respiration.


What is CO2 Used For?

Carbon dioxide is also produced industrially. Due to its properties, it is used, for example, in fire extinguishers, air conditioning units, or in the food industry. CO2 is a gas used, for example, to carbonate popular beverages, especially sodas and beer. Carbonating beverages, among other things, prevents bacterial and fungal growth. CO2 is also used for rapid freezing of food or, for example, to remove caffeine from coffee.

CO2 bubbles - illustrative image

CO2 vs. Life:

It is true that carbon dioxide (CO2) contributes to the greenhouse effect, but it does not necessarily mean catastrophe. Significant greenhouse gases also include water vapor, methane, and ozone. CO2 entered the atmosphere due to volcanic eruptions already in prehistoric times. Its release caused a positive greenhouse effect, which allowed the Earth’s surface to warm to the extent that life could appear here. Without the greenhouse effect, the temperature on Earth would reach only -18°C. Moreover, carbon dioxide is an integral part of the basic process of living nature – photosynthesis and plant growth. With a bit of exaggeration, it could be said that CO2 is actually a manifestation of life.

How is CO2 Formed in Nature?

Most of the carbon dioxide in the atmosphere is of natural origin. It is released, for example, during volcanic eruptions, composting, biomass combustion, etc. As mentioned earlier, carbon dioxide is also produced during the respiration of living organisms. When we inhale, we take in air with an approximate concentration of CO2 of 0.03%, but when the air leaves our lungs, it has a concentration of CO2 of 4%.

Take a look at the following two graphs, which show how rapid population growth is linked to rising CO2 levels:

increasing global population vs. increasing carbon dioxide (CO2) emissions

Interesting Fact:

The average person emits CO2 in various ways including breathing, electricity consumption, heating, driving a car or flying, and other activities – this is called the so-called carbon footprint.

According to rough estimates, an average person emits about 1 kg of CO2 per day through breathing alone, which corresponds to approximately 365 kg of CO2 per year. For perspective, this is the amount of CO2 emitted by an average car when traveling about 3000 km, at an average fuel consumption of 5 liters of gasoline per 100 km. Forgive this gross oversimplification, it’s more of an illustration to give a general idea of how the world works with CO2.

the amount of CO2 produced when breathing vs. the amount of CO2 produced when driving a car 

The total CO2 emissions of a single person are much higher and depend on many factors such as lifestyle, diet, housing and other factors. From transport and industry alone, the global average of CO2 emitted per person is 4.7 tonnes, see charts below.

How Do I Calculate CO2 Emissions for My Vehicle?

CO2 emissions are essentially directly proportional to fuel consumption, so they can be calculated very simply by an approximate calculation. If we know the average consumption in liters per 100 km, we multiply it by a coefficient of 23.92 (for diesel 26.40), and we get the CO2 production. For example, seven liters of gasoline correspond to 166 g of CO2 per km. A more accurate calculation of CO2 production can be found here.

How does transportation contribute to CO2 production?

Transportation accounts for approximately only 12 percent of the total CO2 production! Compared to industry and agriculture, this is not a significant share. Nevertheless, there is enormous pressure on car manufacturers to reduce CO2 production. You can find more interesting graphs here:

 European sources of CO2 production

Where are the main centers of CO2 production / pollution?

Based on statistical data, we can quite easily identify the main centers of carbon dioxide pollution. Among the traditional largest polluters are the USA, Russia, China, but it might surprise some that Canada or states in the Persian Gulf region are also significant. Primarily due to refineries and heavy air traffic, countries like Qatar, United Arab Emirates, Kuwait, and Bahrain produce the most tons of CO2 per capita.

Table of carbon dioxide (CO2) emissions per capita in tons for each country in the given year:

Country CO2
in 1990
in 2000
in 2010
in 2020
Qatar 25.8 62.4 42.8 37.1
UAE 27.2 34.1 21.8 23.3
Kuwait 22.6 28.4 30.9 22.4
Bahrain 22.3 27.0 24.0 25.3
Luxembourg 31.0 20.0 22.1 12.8
USA 20.6 21.3 18.3 14.0
Australia 16.3 18.4 18.4 15.5
Czech Republic 15.9 12.4 11.2 8.7
Russia 17.1 10.1 11.4 11.2
Japan 9.4 10.0 9.5 8.5
Germany 13.3 11.0 10.2 7.8
Slovakia 11.7 7.7 7.1 5.7
China 2.2 2.9 6.4 7.7
India 0.7 0.9 1.4 1.7

CO2 production – interactive emission map of the world:



How much carbon dioxide do newly manufactured cars produce?

If you read an article about calculating CO2 emissions in combustion engines, you will find that the amount of CO2 produced depends mainly on fuel consumption. Sports cars and city vehicles typically have very different fuel consumptions, and therefore different amounts of CO2 produced.

Which brand emits the lowest average fleet CO2 emissions?

Brand Average CO2 emissions [g/km]
in 2003
Average CO2 emissions [g/km]
in 2010
Average CO2 emissions [g/km]
in 2017
Average CO2 emissions [g/km]
in 2020
Average CO2 emissions [g/km]
in 2022
Average CO2 emissions [g/km]
in 2023
Audi 206 159 128 106 99 93
BMW 197 153 122 97 97 94
Ferrari 545 505 358 310 354 341
Ford 190 141 114 97 97 94
Honda 173 134 106 91 91 88
Hyundai 167 128 105 92 92 89
Jaguar 245 192 163 134 129 127
Kia 166 129 105 92 92 89
Lamborghini 495 470 397 382 392 386
Mazda 204 162 127 107 107 103
Mercedes 225 177 129 112 112 109
Nissan 179 136 115 97 97 94
Opel/Vauxhall 182 138 117 96 96 93
Peugeot 166 127 103 93 93 90
Ram 471 412 321 288 218 204
Renault 165 126 100 89 89 86
Skoda 177 137 104 91 91 88
Tesla 0 0 0 0 0 0
Toyota 161 123 93 87 87 84
Volkswagen 181 139 116 99 99 96

source: CHATGTP

What are the average fleet emissions of CO2 in the EU?

The average fleet emissions of carbon dioxide continue to decline, which is certainly a positive trend. However, it needs to be seen in the context of the increasing number of vehicles being manufactured. In 1990, newly manufactured cars emitted an average of 186 grams of CO2 per kilometer driven. By 2010, this had decreased to just 137 grams of CO2 per kilometer. In 2022, it was only 95 g/km, which is actually the basic limit set by the European Union – vehicle emission penalties. However, it should be noted that in 1990, an estimated “only” about 40 million vehicles were produced worldwide, while the estimate for 2020 was about 90 million (though the actual number was ultimately lower due to the COVID-19 pandemic).

Year Total number of manufactured vehicles Average CO2 emissions [g/km]
1990 39 701 000 186
2000 58 374 000 172
2005 69 222 000 163
2010 77 857 705 137
2015 89 691 000 119
2018 95 634 593 111
2019 92 853 006 107
2020 78 794 002 107
2021 83 586 744 101
2022 88 379 486 95
2023 93 172 228 89

source: CHATGTP

Conclusion on the CO2 Issue?

The increasing production of CO2 is indeed a serious global problem that cannot be addressed solely locally, for example, only in Europe! The main reason is that we all share the atmosphere, and when one person smokes in a room, everyone breathes it in!

As we have shown, the growing population of the planet and the related development of human activities have a significant impact on the amount of CO2 in the atmosphere. Each individual has their own needs and carbon footprint, and the size of this footprint depends to some extent on their lifestyle. For these reasons, it is necessary to perceive the increasing production of CO2 primarily in broad contexts. It is good to break free from the popularized notion that “bad” cars are responsible for CO2.

Europe itself, through its green policy (Green Deal), cannot save the world from increasing CO2! The European share of global CO2 production is relatively low compared to global production. Moreover, out of this low share, only 12% is attributed to transportation, as shown in the earlier graph in the text.

Let us realize that further pressure from the EU to reduce CO2 production will be very costly, and its real ecological benefit is likely to be low. If you argue that someone must set an example and be the first, you are certainly right. But will others follow him when they see that he has ruined himself economically and socially?