climate change, climate change impacts, causes of climate change
Greenhouse Gases (cont’d from last blog)
So what does this mean? Why should we care that the concentration of carbon dioxide in the atmosphere is steadily increasing each year?
The reason is: carbon dioxide is a greenhouse gas, which is a gas in the atmosphere that absorbs infrared radiation from the Earth and slows the rate of heat loss. The three major greenhouse gases in the Earth’s atmosphere are water vapor, carbon dioxide, and methane.
To better understand Greenhouse gases think of a car on a hot summer day. After it sits for a long time in the sun with the windows up, it gets pretty hot in there! Sunlight comes in through the windows and warms the car’s interior. If the windows are completely closed, there is no place for this heat to escape. But if the windows are cracked, this creates a place for some of the heat to leave the car. The earth is very much like the car, and greenhouse gases are like the windows.
Greenhouse gases allow sunlight to pass through the atmosphere and reach the earth’s surface. Some of this sunlight is captured as heat on Earth, and some of it is radiated back toward space.
When greenhouse gases are present in the right amounts, they trap just enough heat to keep the earth warm enough for organisms to survive while letting some of that heat back into space. Without greenhouse gases the earth would be a very cold and chilly 0° F (-18° C). This trapping of heat under the atmosphere is called the greenhouse effect.
So if greenhouse gases are so good for us, why do they get such a bad reputation? The problem with greenhouse gases is that they need to be present in specific amounts. When too little gas is present, not enough heat is trapped under the atmosphere to keep the earth warm. When too much gas is present, too much heat gets trapped, which warms the earth more than usual. The types and amounts of greenhouse gases in the atmosphere are only beneficial when they are present in just the right balance.
EPA’s Climate Change Indicators (2014)
The concept and science of Climate change by Glory Oguegbu