大象传媒

The greenhouse effect

Without in its , the Earth would be much colder on average than it is now. Greenhouse gases:

  • absorb transferred as from the Earth鈥檚 surface
  • release infrared radiation in all directions, which keeps the Earth warm

The diagram gives more details about this process, called the .

The greenhouse effect
Figure caption,
How the greenhouse effect works
  1. electromagnetic radiation at most wavelengths passes through the Earth's atmosphere
  2. the Earth absorbs most of the radiation and warms up
  3. the Earth radiates energy as infrared radiation
  4. some of the infrared radiation goes into space
  5. some of the infrared radiation is absorbed by greenhouse gases in the atmosphere
  6. the lower atmosphere warms up

Question

Name three greenhouse gases.