Center for Science Education

Have you ever worn a t-shirt, a long sleeved thermal undershirt, a hot scratchy sweater and a heavy coat on a warm summer day? All those extra layers could cause you to feel overheated. Our planet is also wrapped in outer layers called the atmosphere, which is is full of gases. Most of them are nitrogen and oxygen which have no impact on the climate. In the right amounts, greenhouse gases, like carbon dioxide, methane, nitrous oxide, are helpful, rather than harmful, because they can help regulate the temperature of the planet.

The problem is that human activity has led to a dramatic increase of greenhouse gases in the atmosphere and, like you wearing all of those layers, the Earth becomes overheated.

Not all greenhouse gases have the same heat-trapping abilities. And they don’t all stay in the atmosphere for the same amount of time. So, some greenhouse gases are stronger than others.

Some greenhouse gases cause more warming than others. The chart above shows the relative impact of six greenhouse gases. Compared with carbon dioxide, sulfur hexafluoride (SF6) causes 23,500 times as much warming and tetrafluoromethane (PFC-14), which is used as a refrigerant and in electronics, causes 6,630 times as much warming. Nitrous oxide (N₂O) causes 265 times as much warming and methane causes 28 times as much warming. HFC-152a, which is used as a refrigerant and in aerosol sprays causes 128 times as much warming.

Chart by Our World in Data with data from IPCC (2014)

Carbon Dioxide (CO2)

Carbon dioxide (CO2) is a gas that is naturally-occurring and generated by human and animal respiration that is made of one carbon atom and two oxygen atoms. The right amount of CO2 is important so that people, animals, and plants can breathe.

How strong is it? CO2 has a low heat-trapping ability compared to other greenhouse gases, but there is now so much of it in the atmosphere that it causes much of climate warming. CO2 accounts for a vast 82% of greenhouse gases emissions. CO2 molecules remain in the atmosphere for a long time – after 100 years, 40% of the CO2 that is in our atmosphere today will still be present.

What can we do to reduce CO2 emissions? Besides reducing our use of fossil fuels, we use carbon-negative technology, such as using biochar, a charcoal-like fertilizer that keeps excess carbon underground. Some companies are investigating other options, such as building artificial “trees” to help filter the air.

Methane