How does carbon dioxide cause greenhouse effect?
Any greenhouse gas (CO2 isn’t the only one) works because it’s transparent to light, but not to infrared radiation. So sunlight comes right through it to be absorbed by the earth or sea. This warms the material the light strikes. The warmed material will then re-radiate some of the energy–as infrared light. But CO2 is not transparent to infrared, so it the heat is trapped in the atmosphere. It’s called the “greenhouse effect” because glass has the same property–which is why greenhouses and cars are heated so well by sunlight. As with a greenhouse’s glass, you want a certain amount of heat trapping. The current controversy is whether we have too much “greenhouse effect” at present…
The greenhouse effect is the process in which the emission of infrared radiation by the atmosphere warms a planet’s surface. In the Earth’s atmosphere, the dominant infrared absorbing gases are water vapor, carbon dioxide, and ozone (O3). The same molecules are also the dominant infrared emitting molecules. CO2 production from increased industrial activity (fossil fuel burning) and other human activities such as cement production and tropical deforestation has increased the CO2 concentrations in the atmosphere. Because it is a greenhouse gas, elevated CO2 levels will increase global mean temperature and create the greenhouse effect. So it’s clear that we need CO2 to absorb infrared, but not too much as it will increase global temperature.
