Causes of Global Warming

Over the last 50 year, many scientists noticed that the earth temperature has been increasing by 0.6 ْ C per year. Some people say that it is normal but others are worried of its effects on our planet. However, people are not sure yet if this increase was caused by human activities or by natural causes. In addition, there are many natural factors can affect the earth temperature such as the increase in green house gases, increase in carbon dioxide and other air pollutants. These gases are gathering in the atmosphere and hold the sun’s heat and cause the planet to warm up. Coal-burning power plants and automobiles are the largest sources of carbon dioxide in the world.