How Does Carbon Dioxide Make The Earth Warmer? - Kevin Kurtz

The Sun is providing the Earth and the Moon with pretty much the same amount of heat. The reason the Earth does not have ridiculously extreme temperature changes like the Moon does is because the Earth has its own built-in spacesuit. This spacesuit, which not only protects us from extreme temperatures, but also provides us with oxygen and protects us from being hit by minuscule meteorites, is called the atmosphere.

The atmosphere is the stuff around us we call the air. Even though you can’t see the air, smell the air, or taste the air (if you can see, smell, and taste the air, you may want to move to another town), the atmosphere is filled with gazillions of different molecules, which are little things so tiny you can’t see them even with a microscope. You can feel air molecules, though. If you wave your hand toward your head, the breeze you feel is a bunch of molecules smacking you in the face.

The molecules in Earth’s atmosphere are things such as nitrogen, oxygen, and carbon dioxide that are being gassy (a more accurate way to say that is: they are in their "gaseous state").

Some of these gaseous molecules, called “greenhouse gases,” are what keep the Earth’s atmosphere warm and its temperatures pretty much stable. Greenhouse gases do not warm the atmosphere by making heat, though. Instead, they trap heat from the sun.

The sun is sending heat to the Earth through its rays. Most of the sun's rays that pass through the atmosphere are in the form of ultraviolet waves (the radiation that sunblock protects you from) and visible light (the radiation that allows you to see). Ultraviolet and visible light waves can travel right through the atmosphere (though about half of these waves get blocked by clouds and other things in the atmosphere, which is a good thing for us). When sunlight waves reach the ground, the surfaces absorb their heat. As the ground warms up, that heat eventually will start rising back in the air (when you see a hawk or a vulture soaring around in a circle without flapping its wings, it is able to do so because it is riding rising hot air that was heated by the sun-baked ground). This heat is not released as ultraviolet light (you won’t get a sunburn from the ground) or visible light (you don’t need sunglasses to look at the ground). Instead, because some of the energy of the waves is lost during absorption, the heat from the ground is released as infrared radiation.