The Greenhouse Gas Effect

The greenhouse gas effect can be complicated to understand. It is important because it is the mechanism that causes global warming. By adding excess CO2 from fossil fuels, poor forestry practices, poor agricultural practices, and using carbon-intensive industrial processes, we enable the greenhouse gas effect to increase our planet’s average temperature. Too much of this is going to be a very bad idea, so understanding what is happening is smart. Here are some details with a “sort of” simple explanation to start with.

The sun heats up the plants, the earth, lakes, the air and the ocean. Because the earth gets warm, it radiates heat away from itself back toward space. Infrared radiation is part of the spectrum of light, so the wavelengths of infrared are just colours we can’t see with our eyes. But we can see it with instruments that are sensitive to those wavelengths. Imagine yourself in space looking back at the planet earth, but also imagine that you have eyes that can see infrared wavelengths. If there were no atmosphere, you could see all the wavelengths of infrared displayed as the earth radiates its heat (infrared) back out to space. If we add an atmosphere that contains a little bit of water vapour, ozone, methane, nitrous oxide, and carbon dioxide. Now we can still see some of the infrared, but some of the colours have disappeared and some are not as bright. If we add more of these gases, we still see infrared, but now more colours are completely gone and more are dimmed. The less infrared we can see from space, the warmer the surface of the planet and the atmosphere must be because that infrared is also heat!

The Science Background

That’s one way to imagine how CO2 trapping infrared radiation heading back out to space from the planet can cause an increase in temperature. It is complex. This little video makes it easier to understand.