The greenhouse effect

The Earth receives short-wave radiation from the sun, one-third of which is reflected back out to space. The remaining radiation is absorbed by the surface and heats up the planet. Then the Earth emits infra-red radiation because of the greenhouse gases contained in the atmosphere. This process is responsible for warming the planet. To have a better idea of it let's imagine sunrays inside a greenhouse. In natural situation the heat, the Earth receives from the sun, equals the heat, re-emitted by the Earth. Problems arise when greenhouse gases such as carbon dioxide and methane increase due to human activities and the Earth gets hotter. In one way or another the problem of global warming affects the lives of everyone on the planet. If the weather changes, the level of the sea will rise, there will be floods and not enough food, many animals will die out. The scientists suggest to plant trees because a tree can recycle 48 pounds of carbon dioxide each year.