Global Warming and the Greenhouse Effect

What is the "greenhouse effect?" It is the behavior of solar radiation

when it interacts with gasses in the Earth's atmosphere. The Sun gives

off a wide spectrum of energy which we classify according to its

wavelength. Among the types of energy given off by the sun are

ultraviolet (UV), visible and infrared (IR) wavelengths. UV is short

wavelength high-energy radiation, visible is mid-wavelength,

mid-energy radiation, and IR is long wavelength low-energy radiation.

The atmosphere is mostly transparent to UV and visible light, but some

components of the atmosphere absorb IR energy on its way in toward the

Earth's surface, warming the atmopsphere slightly. When the sun's

energy reaches the surface of the Earth it is absorbed. This warms the

surface, and causes the Earth to emit energy of its own. Unlike the

Sun, however, the Earth does not emit UV or visible light, it ONLY

emits IR energy. As this IR radiation travels back toward space it is

also absorbed by gasses in the atmosphere, particularly CO2, methane

and water vapor.

In this way the Earth's atmosphere acts like the glass in a

greenhouse. The greenhouse lets in the UV and visible light, but once

the interior warms up and IR energy is re-emitted, the glass absorbs

the radiation and does not allow it to escape back to space. This

warms the greenhouse. The fact that all incoming wavelengths are

absorbed by the Earth and re-emitted as IR is the key to the

greenhouse effect, both on the Earth, and in the greenhouse. The

"greenhouse effect" is important to the Earth because it keeps the

planet at a nice, warm, habitable temperature. However, many

scientists, policy makers and c...

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The devastating floods, droughts and storms we have seen in the UK and

across the world in recent years show all too clearly how vulnerable

we are to climate extremes and how high the economic, human and

environmental cost can be, particularly in developing countries.

The greenhouse effect causes trouble by raising the temperature of the

planet. The actual rise is not very much, but the Earth's ecosystem is

very fragile, and small changes can have large effects

Inter-Governmental Panel on Climate Change has predicted that this

rise of one degree will happen by the year 2025

The other serious worry is that rising sea levels from the melting of

the polar ice caps could severely flood many countries. A rise in sea

levels of one metre, which many experts are predicting by the year

2100 (and some as soon as 2030),