The greenhouse effect is easily explained to kids by comparing Earth to a greenhouse full of plants. The glass of a greenhouse traps heat and allows the plants inside to stay warm all year long, while Earth's atmosphere has gases that act the same as the glass of a greenhouse and trap warmth close to the planet's surface.
Various greenhouse gases, such as carbon dioxide, are very important to Earth's atmosphere and climate. The sun warms the Earth, and these gases control the climate by trapping some of the heat and preventing it from escaping back into space. This continuous process between the heat of the sun, the natural gases in the atmosphere and the Earth is called the greenhouse effect. If too many of these gases are produced through activities that do not occur naturally, such as the burning of fossil fuels, the Earth traps too much heat. If too much heat is trapped on Earth, the weather gets warmer and warmer, even in the winter months. This dramatic alteration in the climate harms many organisms because the Earth naturally produces the right balance of gases needed to create the perfect climate to sustain life. This enhanced and dangerous version of the greenhouse effect is referred to as global warming.