Greenhouse Gases List

Tap to Read ➤ Abhijit Naik

Carbon dioxide and methane are the two names that are likely to come to your mind when we talk about greenhouse gases, which isn't really surprising as the two are the most popular of the lot. However, the actual list of greenhouse gases is considerably lengthy and has quite a few names, which you must have never heard of.

Had it not been for the greenhouse gases, the near-surface temperature of the Earth would have been around 59°F lesser than what it is at present. If these gases are so important for the planet, then why are they always portrayed in bad light?

Greenhouse gases (GHGs) are basically the chemical compounds present in the Earth's atmosphere, which help in regulating the near-surface temperature of the planet by absorbing the infrared radiations from the Sun and emitting them within the thermal infrared range.

Like we pointed out in the beginning, if it was not for these gases, the Earth would have been a lot colder, and life would not have been the same for plants, animals, or humans for that matter.

The most prominent names in the greenhouse gases list are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Other than these, the list also includes chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride, nitrogen trifluoride, etc. As these gases are present in the atmosphere in small quantities, they are not as popular as carbon dioxide or methane.

As for the greenhouse gases being portrayed in bad light today, it is primarily because of their contribution to the global warming phenomenon. Most of these gases are notorious for their global warming potential -- an estimate of how much a given mass of any greenhouse gas will contribute to the hazards of global warming.

Abbreviated as GWP, it is determined by the efficiency of the molecule and the atmospheric lifetime of the said greenhouse gas. (The atmospheric lifetime of a greenhouse gas is the estimated average time it will remain in the atmosphere after it has been emitted.)

List of Greenhouse Gases with its Lifetime in Years and GWP* Carbon Dioxide 200 1 Methane 12 25 Nitrous Oxide 114 298 CFC-11 45 4750

CFC-12 100 10900 CFC-13 640 14400 CFC-113 85 6130 CFC-114 300 10000

CFC-115 1700 7370 Halon-1301 65 7140 Halon-1211 16 1890 Halon-2402 20 1640

Carbon tetrachloride 26 1400 Methyl bromide 0.7 5 Methyl chloroform 5 146 HCFC-21 1.7 151

HCFC-22 12 1810 HCFC-123 1.3 77 HCFC-124 5.8 609 HCFC-141b 9.3 725 HCFC-142b 17.9 2310

HCFC-225ca 1.9 122 HCFC-225cb 5.8 595 HFC-23 270 14800 HFC-32 4.9 675 HFC-41 3.7 92

HFC-125 29 3500 HFC-134 10.6 1100 HFC-134a 14 1430 HFC-143 3.8 4470

HFC-143a 52 4470 HFC-152 0.6 53 HFC-161 5.5 12 HFC-227ea 34.2 3220 HFC-152a 1.4 124

HFC-236cb 13.6 1340 HFC-236ea 10.7 1370 HFC-236fa 240 9810 HFC-245ca 7.6 1030 HFC-365mfc 8.6 794

HFC-43-10mee 15.9 1640 PFC-14 50000 7390 PFC-116 10000 12200 PFC-218 2600 8830 PFC-318 3200 10300

PFC-3-1-10 2600 8860 PFC-4-1-12 4100 9160 PFC-5-1-14 3200 9300 Sulfur hexafluoride 3200 22800

Nitrogen trifluoride 740 17200 *100-Year GWP relative to carbon dioxide (CO 2

It is difficult to determine the global warming potential of water vapor and ozone, and therefore they were excluded from this list. That, however, doesn't mean they are less of a threat. In fact, these gases together have a major share in the atmospheric composition greenhouse gases.

Major Greenhouse Gases Water Vapor Water vapor, i.e., the gaseous form of water, which is produced as a result of evaporation of water and/or sublimation of ice, accounts for approximately 33 to 66 percent of the greenhouse gases in the atmosphere.

The concentration of atmospheric water vapor across the globe is uneven, and therefore, it is difficult to determine its global warming potential. Anthropogenic factors, i.e., human activities, do contribute in the formation of water vapor, but the amount of vapor produced in this case is as good as none.

Carbon Dioxide Carbon dioxide features second in the greenhouse gases list, accounting for 9 to 26 percent of total composition. While water vapor is primarily traced to the natural process of evaporation, carbon dioxide is released in air as a result of numerous anthropogenic activities; combustion of fossil fuels being the most important of the lot.

As of May 2013, the concentration of carbon dioxide in the Earth's atmosphere has reached 400 ppm (parts per million) by volume, which is a significant rise from 280 ppm in pre-industrial times.

Methane Methane accounts for anywhere between 4 to 9 percent of the greenhouse gases, but being highly potent, it is a bigger threat to the planet than carbon dioxide.

In fact, its capacity of trapping heat is 25 times that of carbon dioxide. Methane is found in abundance beneath the Earth's crust from where it is released during the process of mining. Studies reveal that the amount of methane in the atmosphere has gone up from 700 parts per billion (ppb) in 1750 to 1,818 ppb in 2011.

Nitrous Oxide Nitrous oxide is a naturally occurring regulator of the stratospheric ozone, which reacts with the ozone and contributes to the greenhouse effect. Averaged over a century, the impact of nitrous oxide per unit weight is 298 times that of carbon dioxide, which makes it a threat for the environment despite its low concentration.

Ozone Constituting approximately 3 to 7 percent of the total greenhouse gases, ozone acts as a greenhouse gas in the upper troposphere, where it absorbs the infrared energy that is emitted by the Earth.

As with water vapor, even the concentration of ozone is uneven, which, in turn, makes it difficult to determine its global warming potential. However, it's believed that the radiative forcing of ozone present in troposphere is approximately 25 percent more than that of carbon dioxide.

Greenhouse effect has long been considered a nuisance for the environment. In fact, some countries have even gone to the extent of banning products which lead to emission of harmful gases, like CFCs.

The Intergovernmental Panel on Climate Change (IPCC) and other government bodies are striving for the betterment of the environment, but these efforts will only be successful when 'we' understand the seriousness of various environmental issues plaguing our planet.