Very very bad. Very very bad. You bad human. Do you know why you were punched in the face? Ok, let me tell you. You were punished because you are causing global warming. Do you know what global warming is? But first, clean your tears, take this hanky. To understand global warming, you first need to understand the greenhouse effect. Do you know about the greenhouse effect? Oh, now you're thinking about a house which is green. Hmm… don't act like you're stupid. There are a few gases in the atmosphere like carbon dioxide, methane and nitrous oxide. These are called greenhouse gases. These greenhouse gases are good if they are in right quantities. These greenhouse gases form a layer around earth. When rays of sun come and fall on earth, some of them are absorbed by earth, but most of them reflect back to the atmosphere. These reflected rays reach the upper atmosphere. There, greenhouse gases take most of the heat from these rays.
Some of the heat goes into space. The heat captured by greenhouse gases spreads in every direction. This heat, which has been trapped by greenhouse gases, helps to keep our earth warm. If the heat of the sun is not stopped by these greenhouse gases, our earth would freeze and the average temperature will be -18 degree celsius. So these gases are good for earth's survival. Otherwise, plants, animals and we humans will have no life here. This stopping of sun heat to keep earth warm is called the greenhouse effect. So greenhouse gases are good. They trap the heat so they help earth to have a nice temperature so that we all can live here happily. Do you know what we humans are doing? We are increasing the amount of these greenhouse gases. We have smoke coming out of vehicles, smoke coming out of factories. In this smoke, there is a lot of methane, a lot of carbon dioxide, which are greenhouse gases.
Also, do you know trees and plants breathe in carbon dioxide thus reducing it from the atmosphere and keeping a balance of greenhouse gases? But unfortunately, we are cutting trees too so there are less plants to absorb greenhouse gases, but more cars and factories to increase these gases. When these greenhouse gases become more and more in the atmosphere, the layer of these gases become more and more thick. So when sun rays come down and get reflected back by earth, they reach this thick layer of greenhouse gases. All these heat rays get trapped and nothing goes up into space. Temperature is increasing, earth is becoming warmer. This is called global warming. So, now you know why you got punched. You, like all of us, are also responsible for global warming. Oh it is too hot today. Good, you have an umbrella. You know an umbrella not only saves us from rain. It also saves us from sun rays. But do you know there is a bigger umbrella made by nature in the sky? In the earth's atmosphere, there is a layer in the stratosphere.
It is called the ozone layer. It is about 15km above the earth's surface. This is the umbrella of the earth. It protects our earth from ultra-violet rays. The sun sends many kinds of rays towards all planets. Out of those rays, ultra-violet rays are very dangerous for plants and humans. Ultra-violet rays are also called UV rays. The ozone layer umbrella absorbs these rays and protects the earth. This ozone layer umbrella does not allow ultra-violet rays to come to earth and harm us. Do you know the harm of ultra-violet rays? These can cause skin cancer, eye cataract, sun burns and less plants. Do you know we humans are destroying this umbrella? By using old kinds of air conditioners, old refrigerators, fire extinguishers and spray cans, we are spreading gases called CFCs. These CFC gases destroy ozone layers by reacting with it. The ozone layer is getting badly affected by these CFC gases.
There are now holes in the ozone layer, but the protective umbrella should have no holes. So if there are holes in the umbrella, UV rays would directly hit the earth. So we humans will have less plants and more diseases. Don't worry. We can protect the ozone layer by using things which don't have CFCs..