Trap Sun
Trap Sun
How does carbon dioxide cause the atmosphere to trap more heat from the Sun?
I want to know the mechanics of it. Why does increasing CO2 cause the atmosphere to warm up?
The molecules of carbon dioxide and other greenhouse gases effectively form a blanket around Earth - more heat enters than is able to escape.
The heat we receive from the sun (solar radiation) has a very short wavelength and is able to pass through the atmosphere unimpeded.
The sun heats the ground, oceans and everything on the planet's surface and this heat is radiated back into the atmosphere as thermal radiation. This has a longer wavelength than solar radiation and some of the heat energy is unable to escape through the blanket of greenhouse gases.
There is more or less a natural equilibrium but in the last 250 years the levels of greenhouse gases have been increasing through the burning of fossil fuels, agricultural activities, deforestation etc. The result has been an increase in atmospheric greenhouse gas concentrations - effectively a thickening of the blanket.
By analysing ice core samples stretching back over the last 650,000 years we know that natural levels of CO2 vary between 190 and 310 parts per million by volume. In recent years levels have risen to 385 ppmv and are still rising.
So, in a nutshell, solar radiation enters the atmosphere and thermal radiation is prevented from escaping, the more greenhouse gases there are the less thermal radiation escapes.
See these sites for more info: http://www.uic.com.au/nip24.htm and http://profend.com/global-warming/pages/causes.html
PS, the previous answerer has photosynthesis the wrong way round - trees and plants absorb CO2 and release oxygen.
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