10 harmful greenhouse gases other than CO2

Did you know that CO2 is not the most powerful greenhouse gas? Since you've learned to read, you've probably learned that carbon dioxide (CO2) harms the environment. But why?

Is CO2 the only greenhouse gas?

Although carbon dioxide emissions account for 84% of all greenhouse gases emitted by humans, they are not the most potent greenhouse gas. However, because it is the most common, it is used as the basis for aggregate reporting of greenhouse gases.

Carbon dioxide equivalent, often measured in metric tons (MT CO2e), has become the standard unit of measurement for climate change-focused sustainability goals and objectives. This is a way to convert greenhouse gases based on global warming potential (GWP) compared to CO2. Standardization allows universal measurement and captures all greenhouse gases such as methane, nitrous oxide and fluorinated gases. For example, the GWP of one metric ton of methane is 29.8 times that of CO2 and therefore corresponds to 29.8 metric tons of CO2 equivalent.

Let's talk about other harmful and common greenhouse gases other than CO2.

Note: GWP values below are based on a 100-year period unless otherwise stated. 

    1. Water vapor (H20)

GWP: Not yet officially measured

Perhaps unsurprisingly, steam, or water vapor, is the most abundant greenhouse gas on the planet.

At one point, the IPCC stated that   water vapor accounts for approximately 60% of the greenhouse effect. However, this figure may be skewed; When water vapor is released into the air it tends to cause a false positive feedback loop. Atmospheric levels increase as the Earth warms, along with the rate of evaporation.

Good news? Water vapor remains in the air for about nine days before turning into rain or snow.

2. Methane (CH4)

GWP: 29.8

Methane is odorless and highly flammable, trapping heat if released without combustion. Common sources of methane come from animal farming (i.e. cattle), which   contributes significantly to climate change. Cattle production and other agricultural practices   produce a quarter of anthropogenic methane emissions

Methane remains in the atmosphere for about ten years.

3. Nitrogen oxide (N₂O)

GWP: 273

If you've ever been to the dentist and used laughing gas, you're familiar with this greenhouse gas. But did you know that this colorless gas is also used in rocket fuel and aerosol?

According to IPCC, it remains in the atmosphere for 114 years.

4. Ground level ozone (03)

GWP: 62–69 (20-year horizon)

Ground-level ozone is a highly irritating gas that occurs above the Earth's surface and is formed when nitrogen oxides and volatile organic compounds react in still air under sunlight.

Approximately 95% of nitrogen oxides from human activities come from the burning of oil, gasoline and coal. Human activities produce volatile organic compounds (VOCs) from solvent evaporation, wood combustion, and gas and oil production.

5. Trifluoromethane (CHX₃)

GWP: 12,400

Trifluoromethane, also known as fluoroform, has two uses: fire extinguishers and silicon computer chip engraving.

It is the most abundant hydrofluorocarbon (HFC) with an atmospheric lifetime of 260 years.

6. Hexafluoroethane (C2F6)

GWP: 12,200

Hexafluoroethane is a refrigerant and is used in semiconductor production. It is the most stable greenhouse gas (FYI, this is not a good thing).

While most gases remain around for hundreds of years, they persist for as long as 10,000 years. Its longevity and high GWP make it one of the most dangerous greenhouse gases.

7. Sulfur hexafluoride (SF6)

GWP: 25,200

Sulfur hexafluoride is used as an insulator in electrical power systems, in dispersing chemicals, and in various scientific experiments. Good news for those dependent on sulfur hexafluoride:  Safer alternatives are available.

While sulfur hexafluoride contributes a smaller percentage to greenhouse emissions, the colorless and odorless gas is the most potent greenhouse gas, remaining in the atmosphere for 3,200 years.

8. Trichlorofluoromethane (CCl3F)

GWP: 4,600

Trichlorofluoromethane, a gas used as a coolant in refrigerators and to make foam in liquid fire extinguishers, disrupts the global climate on two fronts. First, the gas  produces chlorine molecules that deplete the ozone layer  and, as you might expect, has a high GWP.

9. Perfluorotributylamine (C12F27N)

GWP: 7,100

Cooling CPUs in the electronics industry Perfluorotributylamine (PFTBA), which has been administered for over 50 years in China and as a component of artificial blood, has recently come on the radar as a potentially harmful greenhouse gas. Although its concentration in the atmosphere is relatively low (about 0.2 parts per trillion), the gas can remain there for more than 500 years.

10. Sulfuryl fluoride (SO2F2)

GWP: 4,780

Sulfuryl fluoride, a fumigant used to manage termites, was only identified as a greenhouse gas by MIT scientists in 2009 .

Sulfuryl fluoride is highly inert and has an atmospheric shelf life of up to 40 years. The chemical only takes up 1.5 parts per trillion in the atmosphere, but that figure is increasing by 5% each year.