Global Warming

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Global Warming

Our planet's atmosphere traps energy just like a greenhouse. Energy

from the Sun can enter the Earth’s atmosphere, but not all of it can

easily find its way out again.

What blocks the Sun’s energy from escaping from the Earth? Unlike a

greenhouse, the Earth does not have a layer of glass over it! Instead,

molecules in our atmosphere called greenhouse gasses absorb the heat.

Greenhouse gasses include water vapor, methane, ozone, nitrous oxide,

and carbon dioxide. There may not be much of some of these gasses in

our atmosphere, but they can have a big impact. Each greenhouse gas

molecule is made of three or more atoms that are bonded loosely

together. These molecules are able to absorb heat, which makes them

vibrate. They eventually release the heat energy and it is often

absorbed by another greenhouse gas molecule.

The greenhouse effect is useful because trapping some energy keeps the

temperatures on our planet mild and suitable for living things.

Without its atmosphere and the greenhouse effect, the average

temperature at the surface of the Earth would be zero degrees

Fahrenheit. However, too many greenhouse gases can cause the

temperature to increase out of control. Such is the case on Venus

where greenhouse gases are abundant and the average temperature at the

surface is more than 855 degrees Fahrenheit (457 degrees Celsius).

We have increased the amount of carbon dioxide in the atmosphere by

burning fossil fuels, such as coal, oil and petrol. Cows, rice fields

and rubbish rotting in landfill sites produce methane, and aerosols

and fridges use CFCs.

The removal of trees - deforestation - is also thoug...

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...warming.

The theory for these rapid rises and falls of temperature, based on

the geological records from 55 million years ago, is that gradual

global warming due to some natural cause had resulted in temperatures

5 to 7 degrees centigrade higher than average ( i.e. higher than

today's temperatures). At this point methane trapped in methane

hydrate deposits started to be released into the atmosphere and

accelerated the rate of warming. This would result in further warming

releasing more methane. As the atmosphere warmed different types of

methane deposits would start to be released and so a cycle of methane

release leading to increased warming leading to more methane release

from other areas of methane deposits elsewhere in the world would

become established as global warming effected different areas of the

world.

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