Have
you ever seen a greenhouse? Most greenhouses look like a small glass
house. Greenhouses are used to grow plants, especially in the winter.
Greenhouses work by trapping heat from the sun. The glass panels
of the greenhouse let in light but keep heat from escaping. This
causes the greenhouse to heat up, much like the inside of a car
parked in sunlight, and keeps the plants warm enough to live in
the winter.
The
Earths atmosphere is all around us. It is the air that we
breathe. Greenhouse gases in the atmosphere behave much like the
glass panes in a greenhouse. Sunlight enters the Earth's atmosphere,
passing through the blanket of greenhouse gases. As it reaches the
Earth's surface, land, water, and biosphere
absorb the sunlights energy. Once absorbed, this energy is
sent back into the atmosphere. Some of the energy passes back into
space, but much of it remains trapped in the atmosphere by the greenhouse
gases, causing our world to heat up.
The
greenhouse effect is important. Without the greenhouse effect, the
Earth would not be warm enough for humans to live. But if the greenhouse
effect becomes stronger, it could make the Earth warmer than usual.
Even a little extra warming may cause problems for humans, plants,
and animals.
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