The Heat You Can’t See: Greenhouse Gases Explained

We hear the most about carbon dioxide (CO2) because it’s the main greenhouse gas causing climate change. Most of the CO2 comes from burning fossil fuels like coal, oil, and gas for things like electricity, cars, and factories. Since humans produce so much of it every day, CO2 has the biggest long-term impact on Earth’s temperature. That’s why people talk about it the most. We just reached 430 ppm CO2, a more than 50% increase since 1750.

CO2 levels haven’t been this high in millions of years. That’s way before humans—or even most of the animals and plants we know today—existed. That’s a big warning sign for our planet.

Don’t Forget Methane—The Climate’s Other Heavy Hitter

Methane is a strong greenhouse gas that helps warm the planet. It’s the second biggest cause of climate change after carbon dioxide (CO2). Even though there’s less methane in the air, each methane molecule traps more heat than a CO2 molecule. But it doesn’t last as long—methane stays in the atmosphere for about 7 to 12 years. On the other hand, CO2 can stick around for hundreds of years.

Where Does Methane Come From?

Methane comes from both nature and human activities. Today, about 60% of methane pollution comes from things people do—like farming, using fossil fuels, and trash rotting in landfills. The other 40% comes from natural places like wetlands, which are the biggest natural source.

As the planet warms, it releases even more methane into the air, which makes climate change worse. For example, when frozen ground in the Arctic—called permafrost—starts to melt, it can release methane that was trapped for thousands of years. Warmer temperatures can also cause wetlands to produce more methane and make it easier for methane to leak from places like oil and gas wells. This extra methane adds more heat to the atmosphere, creating a dangerous cycle where warming causes more methane, and more methane causes more warming.

The Lesser-Known Greenhouse Gases

Did you know there are some lesser-known gases that also trap heat and warm our planet—like ground-level ozone, nitrous oxide, and chlorofluorocarbons (CFCs).

Ground-level ozone isn’t released directly into the air. Instead, it forms when sunlight reacts with pollution from cars, factories, and power plants. While ozone high up in the atmosphere is a good thing—it protects us from the Sun’s harmful rays—ground-level ozone is harmful—it pollutes the air we breathe and acts like a powerful greenhouse gas, adding to global warming.

Nitrous oxide (N₂O) is sometimes called “laughing gas,” but it’s no joke for the climate. Although there are natural sources of N₂O from soil microbes, the ocean, and wetlands, there are also human-caused sources. The biggest sources comes from farming—especially from fertilizers used on crops and animal waste. It’s about 300 times stronger than carbon dioxide at trapping heat. That means one molecule of N₂O traps as much heat as 300 molecules of CO₂! and it can stay in the atmosphere for over 100 years.

Chlorofluorocarbons (it’s a mouthful!), or CFCs, were chemicals once used in things like air conditioners, refrigerators, and spray cans. They’ve mostly been banned now because they also destroyed the ozone layer that protects Earth from ultraviolet radiation. But CFCs are still in the atmosphere from past use, and they’re very powerful greenhouse gases—thousands of times stronger than CO₂. In addition, scientists recently found signs of new CFC-11 pollution, which may mean someone is still making or using them illegally.

Even though CFCs are much less common than carbon dioxide in the air, they’re about 10,000 times stronger at trapping heat and can stay in the atmosphere for 45 to 100 years.

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Bottom line: Every greenhouse gas we release—whether it’s carbon dioxide, methane, or CFCs—adds more heat to our planet and puts our future at risk.

We need to cut emissions now by switching to clean energy, protecting forests, and pushing for strong climate action—because every bit of warming we prevent matters.