A
lot of people think that the atmosphere is just air; but it's more complex
than that. It's actually a mixture of gases that surrounds the Earth.
These gases perform many functions and help to support life on our planet.
Earth
is a Huge Greenhouse
Greenhouses
use glass to keep the heat in. The atmosphere traps the sun's heat near
the Earth' s surface in the same way as the glass does in a greenhouse.
It keeps the Earth warm using what are called "greenhouse gases".
Without these gases, the sun's heat would escape and the average temperature
of the Earth would drop from 15 degrees Celsius to -18 degrees Celsius!
Greenhouse
gases and climate change
For
thousands of years, the Earth's atmosphere has changed very little. The
temperature and the careful balance of greenhouse gases have allowed humans,
animals and plants to survive. But today we are having problems keeping
this balance. Because we burn fossil fuels to heat our homes, run our
cars, produce electricity and manufacture all sorts of products, we are
adding more greenhouse gases to the atmosphere. These activities are changing
the atmosphere at a greater rate than humans have ever experienced. |
