So What Is a Greenhouse Gas, Anyway?

We’ve been hearing about greenhouses gases and their effect on climate change for decades. But typical news reports don’t go into the what, how or why of these emissions — so let’s cover the basics.

The Greenhouse Effect

This physical phenomenon is the main way the Earth retains heat. The greenhouse effect impacts the climate by altering global air currents, shifting regional moisture and increasing available energy — thereby increasing the frequency and power of extreme weather events, like hurricanes.

The greenhouse effect also indirectly impacts ecosystems and the climate by changing plant growth and animal migration, as well as by melting permafrost and releasing trapped gases into the atmosphere — some of which further contribute to the greenhouse effect.

But what is the greenhouse effect?

Greenhouses are used by horticulturalists to raise plants that cannot be easily grown in the open air. Also known as hothouses, greenhouses are not typically heated by a thermostat-controlled system. Instead, the walls and ceiling are made primarily of glass, to allow lots of sunlight to reach the plants.

But the type of glass used is also one that prevents heat loss, because it allows UV and visible rays in sunlight to pass through, while blocking infrared light — the main kind of radiation emitted from warm objects, and a major method of heat loss. In other words, the glass in greenhouses seals in heat.

Greenhouse gases include any gas whose chemical structure mimics this property. If you increase the concentration of greenhouse gases in our atmosphere, the air itself becomes more and more like a pane of greenhouse glass. That is, sunlight continues to come through, carrying with it all kinds of energy all the way down to the soil and plants and buildings those rays strike.

However, as more of these heat-insulating gases enter into the atmosphere, the planet becomes even better at holding in heat, and the overall average temperature increases.

Significant Greenhouse Gases

Carbon dioxide is one of the most well-known greenhouse gases, not because it is the most potent but because we produce so much of it — and have no easy way of reversing this process.

Carbon dioxide, or CO2, is naturally produced by all living things each time we respirate, however plants are also constantly taking in carbon dioxide as part of the chemically-opposite process of photosynthesis. In theory, this should balance out — as long as we don’t radically increase CO2 production or reduce’s the world’s plant population. Unfortunately, we’ve continued a pattern of burning coal for electricity, burning gasoline for motor vehicles and destroying forests. Besides the greenhouse effect, a higher CO2 concentration can also contribute to ocean acidification.

Methane is an even more potent greenhouse gas. This chart compares some of the key numbers between greenhouse gases, and you’ll see that methane has 25 times the effect of global warming compared to the same number of particles of CO2.

Humans contribute to a higher atmospheric methane concentration by storing garbage in landfills and through industrial farming, particularly cattle-raising. On the plus side, methane has a shorter life in the atmosphere compared to CO2, so we could see a fairly quick improvement in greenhouse gas mitigation efforts if we severely curbed methane production. But if we fail to do so, methane will undoubtedly increase global temperature.

Water is not much of an issue by itself, as there is pretty well a constant amount on the planet — unlike CO2 produced by burning fossil fuels. That said, water vapor in the atmosphere has a substantial effect on capturing infrared heat radiation and keeping it from escaping into space.

The amount of water vapor increases over time, as higher temperatures mean more liquid water evaporates and enters into the atmosphere as vapor. So each time we increase the concentrations of other greenhouse gases and the global average temperature goes up, the amount of water vapor will also increase. Therefore, water magnifies the effect of everything else. Water vapor is one of several examples of positive feedback loops and tipping points that could lead to ever more accelerated rates of warming over time.

What to Take Away

Each gas has a lesson for us. CO2 is long-lived in the atmosphere — easy to produce but hard to get rid of. The lesson here is to cut back on emissions quickly and decisively, as there’s no easy fix later for what could be avoided now.

Methane, as an even more powerful greenhouse gas, shows us we could focus on high-yield targets  and make an immediate and major impact on climate change alongside our long-term transitions.

The lesson of water is that warming will not always be predictable and steady. There will be times in our changing climate when there could be sudden jumps in temperature and major shifts in weather. We can’t do anything about the water vapor;  it’s just part of the price of messing with the planet’s atmosphere — and one more reason to control and limit our production of other greenhouse gases.

Photo Credit: Jason Blackeye/Unsplash


Marie W
Marie W2 months ago

Thanks for sharing.

Frances G
Frances G4 months ago


David C
David C4 months ago

Don't Give UP! We still can save the world from ourselves!

Renata B
Renata B6 months ago

Very good article: thank you.

Clare O
Clare O6 months ago


Danuta W
Danuta W6 months ago

Thank you for sharing

Peggy B
Peggy B6 months ago


Chad Anderson
Chad Anderson6 months ago

Thank you.

danii p
danii p6 months ago

Thank you

danii p
danii p6 months ago

Thank you