Greenhouse Gases - (GHGs)

&

“The Greenhouse Effect”

MODULE #1: Climate Change & Global Warming

What are Greenhouse

Gases?

Photo courtesy of SEAWIFS

They are gases that are transparent to sunlight but opaque to heat radiation…

In other words, sunlight passes through but heat rising from Earth gets trapped by themExamples:

carbon dioxide

methane

nitrous oxide

CFCs, PFCs, SF6

tropospheric ozone

How do Greenhouse Gases cause “The Greenhouse Effect”?

S U N

““The Greenhouse Effect”The Greenhouse Effect”

A natural (and balanced) “Greenhouse Effect” created by gases (water vapor, carbon dioxide and other gases) in our atmosphere allows us to live comfortably here on planet Earth.If there was no natural greenhouse effect, the average global temperature would be about 60°F colder than we experience now.Our weather and climate are controlled by how much of the sun’s energy actually gets trapped.

To learn what this has to do with Climate Change / Global Warming, please take a look at MODULE #2 …

Greenhouse gas molecules, like carbon dioxide, absorb much of this heat and re-release it back to the Earth & the atmosphere

The Sun’s rays travel through space, and then through the Earth’s atmosphere

Some of these rays are reflected back into space off of clouds and light-colored objects on the ground

…but much of the sunlight’s energy heats up the dark-colored objects on the Earth. This energy is then released back into the air in the form of heat (infrared radiation)

What happens to temperatures on Earth if we add lots of greenhouse gases to the atmosphere in a very short period of time (and upset this delicate natural balance)?