People often hear the term “greenhouse effect” used negatively in discussions that have to do with global warming. But this is not a negative event in itself, it is actually a major part of Earth’s energy balance. This is what causes the Earth to be warm enough for the planet to remain habitable for humans, plants, and animals alike. Without it, nothing would be able to survive and the Earth would feel a lot more like the Mars.
The greenhouse effect got its name from the actual greenhouses people use to keep their plants from dying in the cold air. This is very similar to the way that the Earth keeps itself warm enough for life to survive. Sun rays enter our atmosphere and the heat absorbs itself in the land and oceans in which we live. Only about one-third of the solar energy that enters our atmosphere is reflected back into space by water, glaciers, and other very bright surfaces. The other two-thirds of the energy soaks itself deep in the Earth’s crust.
Infrared radiation: This is what causes the Earth to warm once it enters out atmosphere. This only makes up about one half of all the solar energy that enters our atmosphere. The other half of the solar energy is of a much higher frequency. This turns into heat once its hits the Earth’s surface, but it later will be reflected back into the universe as waves of radiation. It is very crucial that solar radiation transforms into infrared radiation, because this is the only way it can be absorbed into the atmosphere.
There are gases in the air that absorb this radiation including water (H2), carbon dioxide (CO2), Ozone (O3), nitrous oxide (NO2), and methane (CH4). These gases act like a heating insulation to keep the earth warm. If we did not have this the Earth would be at an average of -25 degrees below zero at all times.
Water vapor in the atmosphere has a much higher concentration level than that of carbon dioxide. Therefore, most of the energy that is absorbed is attributable to water. You can actually see this effect for yourself. Notice how it seems to be much cooler on nights were there are many clouds in the sky compared to the temperature when the sky is clear and free of clouds.
Even though the carbon dioxide concentrations in the atmosphere are not nearly as high as water or other gases, it is slowly increasing over time. Many believe that human activities are the cause of this increase. For example, our consumption of fossil fuels and the clearing of many forrests makes it that less carbon dioxide can be consumed by photosynthesis. This is causing additional CO2 to be released into the atmosphere, and therefore will absorb more heat causing the earth’s temperature to rise. This is why we continue to hear more and more about global warming.