Scientific evidence tells us that human activity is altering the basic conditions for life on Earth. Changes in the atmosphere caused by the emission of heat storing gases are expected to lead to an increase in temperature globally, rising sea levels, and erratic weather cycles.

What is the Green House Effect?
The science behind the greenhouse effect is based on three principles:

1. In the mid 19th century scientists found that each gas has a different capacity to retain and hold heat. Oxygen and Nitrogen loose heat rapidly whereas Carbon Dioxide is very good at holding heat.
   
   
2. The ability of some gases to retain heat is very important for the functioning of the atmosphere. They allow the suns rays pass through the atmosphere and warm the earth and then they prevent that heat from being radiated back into space. They function like the glass in a greenhouse, letting through the suns rays and then holding in the heat. This is the reason for the term greenhouse effect.
   
   
3. The gases that have the quality of retaining heat in the atmosphere are called "greenhouse gases". The most concentrated one is Carbon Dioxide. There are other gases in the atmosphere which are far more powerful but are present in far smaller concentrations for example Methane retains 25 times as much heat as Carbon Dioxide and Nitrous Oxide 320 times, but there is a great deal less of these gases to worry about.

The greenhouse effect is in itself not a bad thing, on the contrary it is essential for the Earth to hold life, because without greenhouse gases in our atmosphere the earth would be as cold as the moon. The problem is not Greenhouse Effect but the emission of greenhouse gases.

Why has the Green House Effect become a problem?

Since the industrial revolution the world has relied increasingly on burning fossil fuels to provide the energy we need. Every time we burn these fuels we produce more carbon dioxide. 8 billion tons a year in fact. Within 50 years we will have twice as much Carbon Dioxide in the atmosphere as we had before industrialisation. Nitrous Oxides another powerful greenhouse gas is also a by product of burning fossil fuel. We all contribute to this through our carbon intensive lifestyle, our cars, home heating, and air travel.

There are also new gases in the atmosphere such as CFC's (Chlorofluorocarbons) which are used in refrigerators and, although they are present in tiny quantities relative to carbon dioxide they are 9,000 times more powerful at retaining heat (which is what made them so good for refrigeration in the first place!)

The change in the atmosphere will mean that far more of the sun's energy is held within the Ozone layer, throwing all existing climate systems into chaos. Computer predictions estimate global temperature increases over the next 100 years of across the world by up to 6°C. Scientists know of no time when temperatures have risen faster and beyond 2°C increase find it hard to make reliable predictions of the actual effects in the weather. In the next fifty years we will see ever increasing extremes of weather. More storms, floods, droughts. The natural world will not be able to adjust fast enough. By 2050 climate change will have directly led to the extinction of 30% of species, the death of 90% of coral reefs and the loss of half the Amazon rainforest.

So climate change can be summed up in two points:

1. Different gases have different capacities to retain heat.
   
   
2. When we change the gases in the atmosphere, we will change the way that it holds in the heat from the sun.

It is absolute scientific fact that the changes we are making to the concentrations of different gases will effect the way the atmosphere behaves.

CLIMATE CHANGE HAS ALREADY STARTED

This is not some vague future threat. All around the world rapid changes in the weather are already happening. In the last 10 years we have become aware of increasing temperatures, melting icebergs, and erratic "unusual" weather has become commonplace.

If we don't take action it will become far worse
Beyond 2050 we face the acceleration of the process of climate change. Carbon and methane stored in soils and oceans will start to leak into the air and the natural processes in forests and oceans that remove carbon dioxide from the air will break down.

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