CAUSES & THREATS OF<br />GREEN HOUSE EFFECT<br />
What does a greenhouse look like?<br /><ul><li>Most greenhouses look like a clear mini glass house. They are used to grow plants in any environment. Greenhouses work because when the sun comes out the green house can trap the sunlight and use it to grow plants. The glass panels trap as much sunlight as possible but keeps heat in. This causes the greenhouse to heat up and help the plants grow.</li></li></ul><li>How is the earth like a greenhouse?<br />Like a greenhouse the earths atmosphere traps heat and energy from the sun.<br />
The Greenhouse Effect on Earth<br /> Earth’s atmosphere is slightly warmer than what it should be due to direct solar heating because of a mild case ofgreenhouse effect…<br /><ul><li>The ground is heated by visible and (some) infrared light from the Sun.
The majority of Earth’s atmosphere (N2 and O2) are not good greenhouse gas.
The small amount of greenhouse gases (H2O, CO2) traps (absorb and re-emit) the infrared radiation, increasing the temperature of the atmosphere…</li></li></ul><li>incoming<br />radiation<br />Solar energy reaches the Earth’s surface<br />
So, what’s the big deal if human CO2 causes 1°C temperature increase?<br /><ul><li>An increase in atmospheric temperature (human or natural origin) will lead to the increase in the water vapor content of the troposphere.
Because water vapor is a strong greenhouse gas, the increase in H2O vapor in turn causes enhanced greenhouse effect, raising the temperature more.
Higher atmospheric temperature will cause more evaporation of water
Which leads to even higher temperature…</li></ul>Runaway Green House Effect!<br />
Climate models suggest that the changes are just beginning now and will accelerate.<br />
Arctic Ice Melting Faster Than Predicted<br />
Greenhouse Gases<br /><ul><li>The primary components of Earth’s atmosphere, N2 and O2 do not have absorption in the IR wavelength range, therefore, do not have a significant role in setting the surface temperature of the planet…
Greenhouse gas are efficient in absorbing IR light…</li></ul>The most important greenhouse gases are:<br /><ul><li>H2O – Water vapor.
The most abundant greenhouse gas in Earth’s atmosphere is water vapor. Most of the greenhouse heating of Earth’s atmosphere is due to Water vapor absorption of IR radiation emitted by Earth, and then transferring the energy to the surrounding air molecule</li></li></ul><li>Greenhouse Gases<br />The following pie chart displays the percent of each gas<br />which plays a role in the greenhouseeffect.<br />
How we contribute<br /><ul><li>Burning natural gasses
Sequester (remove) carbon from the atmosphere.
If all excess carbon dioxide release stopped today, it is estimated that it would take hundreds of years for levels to return to normal (NASA, 2007).</li></li></ul><li>Without It<br /> Without the greenhouse effect, the Earth would not be able to support life. But if the greenhouse effect becomes too strong, the earth will be too hot to support life. Even a little to much heat could hurt the animals, plants, and everything else on the planet. Without the gasses that surround the planet, heat would escape back into space, causing the earths average tempter to be about 60 degrees colder.<br />
Runaway Greenhouse Effect<br />If we were to move the Earth closer to the Sun, like where Venus is now, then we would suffer the runaway greenhouse effect as well, lose all the water, and become hot like Venus.<br />
Other planets also have Greenhouse Effects, <br />but these are unsuitable for life<br />Venus<br />Atmosphere: mass 90x earth’s<br />GH Gases: >90% CO2<br />Sfc. Temp.: 477C<br />GH Effect: 523C<br />FAR TOO HOT!<br />Earth<br />GH Gases: ~0.04% CO2<br /> ~ 1% H2O<br />Sfc. Temp.: 15C<br />GH Effect: 33C<br />NOT BAD!<br />Atmosphere: mass <1% earth’s<br />GH Gases: >80% CO2<br />Sfc. Temp.: -47C<br />GH Effect: 10C<br />FAR TOO COLD!<br />Mars<br />Sun<br />
SUMMARY<br />Greenhouse gases absorb infrared radiation and prevent it from escaping to space.<br />Carbon dioxide, methane, and nitrous oxide are very good<br />At capturing energy at wavelengths that other compounds<br />