Global warming is caused by humans, not the sun. What is global warming? Carbon dioxide and other air pollutants accumulate in the atmosphere as an ever-thicker blanket, trapping the sun's heat and causing the planet to warm. Coal-fired power plants are the largest source of carbon dioxide pollution in the United States: they produce 2.5 billion tons each year. Cars, the second largest source, create nearly 1.5 billion tons of CO2 per year. The planet is changing faster than expected, with the earth getting hotter and coal-fired power plants responsible for the most carbon dioxide pollution. Coal-fired power plants are the largest source of carbon dioxide pollution in the United States. So you might ask: what is coal for? Well, coal is a black sedimentary rock. It is formed from high pressures and temperatures, from organic matter that lived millions of years ago, through a process called coalition. The amount of carbon, hydrogen and oxygen in coal are the main factors during combustion. The amount of carbon determines the amount of CO2 emitted...