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Carbon dioxide -

Carbon dioxide (or CO2) is the main greenhouse gas emitted from human activities. In 2022, for example, it accounted for 80% of all US greenhouse gas emissions from human activities.

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How it works -

Carbon contributes to the warming planet, because it traps infrared radiation coming off the Earth and prevents it from returning back to space.

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Transportation -

The main way that humans produce carbon dioxide is by burning fossil fuels. And one of the biggest culprits when it comes to fossil fuels is the transportation industry.

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Electricity -

Another reason that we burn fossil fuels is to create electricity, which is a key source of energy in countries all over the world.

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Industry -

There are also various industrial processes that do not involve combustion, but which nonetheless produce CO2, such as the production of cement.

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Forestry -

When it comes to land management and forestry, there are processes that emit CO2. However, in general, the management of forests and land serves to absorb more CO2 than it emits.

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Reducing carbon dioxide emissions -

The best way to reduce carbon dioxide emissions from human activities is to stop burning fossil fuels. All over the world countries have already introduced cross-cutting strategies that apply to homes, businesses, industry, and transportation.

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Methane -

Next up we have methane, a natural gas that, in 2022, accounted for 12% of all US greenhouse gas emissions from human activities.

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How it works -

Methane serves to warm the planet by absorbing long-wave radiation, thereby trapping heat that would otherwise escape into space.

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Livestock -

There are a number of human activities that produce methane, the first being the management of livestock: cattle, swine, sheep, and goats all produce methane as part of their natural digestive process.

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Land use -

Methane emissions also occur as the result of certain land management activities, including methods used to manage flooded lands, such as reservoirs.

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Energy and industry -

Then we have the natural gas and petroleum systems. Methane is released into the atmosphere during the production and storage of crude oil, for example.

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Landfill -

The third-largest source of methane emissions in the US are landfills: methane is produced in landfills as waste decomposes and waters are treated.

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Natural emissions -

It is important to note, however, that methane is also emitted from several natural sources. Natural wetlands, for example, emit methane from the bacteria that decompose the organic material found in them.

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Nitrous oxide -

The third important greenhouse gas is nitrous oxide, which in 2022 accounted for 6% of all US greenhouse gas emissions from human activities.

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Potent -

In terms of its warming effect, nitrous oxide is particularly potent: one pound (0.45 kg) of the gas will warm the atmosphere roughly 300 times more than one pound of CO2 over a 100-year period.

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Agriculture -

One of the key industries responsible for the production of nitrous oxide is agriculture. Various agricultural activities, such as the application of fertilizers, can cause nitrous oxide to escape into the atmosphere.

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Burning fuels -

Nitrous oxide is also emitted when we burn fuels, although the amount largely depends on the type of fuel as well as the combustion technology, maintenance, and operating practices.

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Industry -

Another process that creates nitrous oxide as a byproduct is the production of chemicals, such as nitric acid. Nitric acid is used to build synthetic commercial fertilizers.

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Treating wastewater -

Finally, nitrous oxide is also generated during the treatment of domestic wastewater.

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Natural sources -

It is important to note that nitrous oxide is also produced during many processes associated with the nitrogen cycle, which is the natural circulation of nitrogen among the planet's atmosphere, plants, animals, and microorganisms.

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Fluorinated gases -

Finally, we have fluorinated gases. These are unique in the sense that they have no natural source; they are only created by human activities.

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Refrigerants -

One way in which fluorinated gases are emitted is through their use as a substitute for ozone-depleting substances, such as refrigerants.

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Industrial processes -

There are also various industrial processes that have fluorinated gases as a byproduct, such as manufacturing aluminum and semiconductors.

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High global warming potential -

Many fluorinated gases have a high global warming potential, which means they have a large effect on global temperatures even in small concentrations.

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Long atmospheric lifetime -

Fluorinated gases also have a long atmospheric lifetime. And like other long-living greenhouse gases, they spread all around the world after being emitted.

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How they are removed -

In fact, many fluorinated gases are only removed from the atmosphere when they are destroyed by sunlight in the upper atmosphere.

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Final thoughts -

Overall, fluorinated gases are the most potent, as well as the longest-lasting, greenhouse gases emitted as the result of human activities.

Sources: (EPA)

See also: These foods could help reverse climate change

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