So, what are the greenhouse gases that are enhancing the greenhouse effect? As mentioned before, greenhouse gases naturally occur in the atmosphere, but human production has been increasing the concentration of certain ones faster than they can break down. This increase is mainly due to human activities such as burning fossil fuels (like coal, oil and natural gas) and excess methane production from livestock and landfills.
The most important greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide, ozone and fluorinated gases.
Water vapor is the most abundant and possibly the most important greenhouse gas. Water vapor is not only very good at trapping heat on Earth but also amplifying the effects of other greenhouse gases. Water vapor does this through a vicious cycle: as the amount of water vapor increases in the atmosphere, the temperature on Earth increases as well, which then causes more water vapor absorption in the air, which again increases the warming of the earth…you can see how this is an issue!
Carbon dioxide (CO2) comes from the burning of fossil fuels and is important because even though it’s not the most potent greenhouse gas, it is one of the most abundant. CO2 concentrations naturally fluctuate over time, but recently reached a milestone concentration of 400 parts per million. To put this in perspective, in the past 800,000 years it has not been over 300 parts per million.
The real worry though is how quickly CO2 is accumulating in the atmosphere. Since the beginning of the Industrial Revolution (about 1750), human activity has continually increased atmospheric CO2 levels from 280 parts per million to the current high. There is no other period in the history of Earth where CO2 levels have increased so quickly.
Methane (CH4)is also rapidly increasing in the atmosphere. Methane is released into the air from fossil fuels and livestock. Atmospheric methane has increased 151% since the beginning of the Industrial Revolution and is currently at its highest concentration in at least 650,000 years.
Nitrous oxide (N2O) : Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.
Fluorinated gases : Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydro chlorofluorocarbons, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases (“High GWP gases”).
Each gas’s effect on climate change depends on three main factors:
How much of these gases are in the atmosphere?
Concentration, or abundance, is the amount of a particular gas in the air. Larger emissions of greenhouse gases lead to higher concentrations in the atmosphere. Greenhouse gas concentrations are measured in parts per million, parts per billion, and even parts per trillion. One part per million is equivalent to one drop of water diluted into about 13 gallons of liquid (roughly the fuel tank of a compact car). How long do they stay in the atmosphere?
Each of these gases can remain in the atmosphere for different amounts of time, ranging from a few years to thousands of years. All of these gases remain in the atmosphere long enough to become well mixed, meaning that the amount that is measured in the atmosphere is roughly the same all over the world, regardless of the source of the emissions.
How strongly do they impact global temperatures?
Some gases are more effective than others at making the planet warmer and “thickening the Earth’s blanket.”
EPA’s Climate Change Indicators (2014)
The concept and science of Climate change by Glory Oguegbu