Global Warming: Good or bad?

IS GLOBAL WARMING HAPPENING?

Plants grow better in a greenhouse because it's warmer inside than outside. Sunlight passes through the glass. The plants and other objects inside the greenhouse absorb the light, and they give out some infrared radiation. This cannot pass through the glass, so it is kept inside the greenhouse, warming the air and everything else inside.

The atmosphere around the Earth acts like the glass in a greenhouse. Sunlight passes through the atmosphere to the Earth's surface. The Earth gives out infrared radiation, and some gases in the atmosphere reflect this back to the Earth rather  than letting it go out into space. This keeps the Earth warmer than it would otherwise be. Without this greenhouse effect, life as we know it would not exist.

GREENHOUSE GASES: WHAT'S THE PROBLEM?

The gases in the atmosphere that reflect the infrared radiation are called greenhouse gases. They are shown down:

greenhouse gas:                    produced by:

Carbon Dioxide                         - Burning fossil fuels for generating electricity and for transport; also by respiration, rotting organic material, volcanic eruptions

Methane                                      - Rotting organic material (agriculture and landfill sites)

HFCs (hydrofluorocarbons)      

CFCs (Chlorofluorocarbons)    - CFCs used to be used in aerosols and fridges but they caused damages to the ozone layer. Now HFCs are used instead

NOx                                              - Traffic pollution, also produced naturally by bacteria

Water Vapour                              - Many natural sources, burning fossil fuels

The problem is that we are producing more and more greenhouse gases. Scientists think that because of this the greenhouse effect is increasing, making the Earth warmer. This is called global global warming.

The Earth's average temperature has warmed by 0.6ºC over the last 100 years or so. Some people predict that the average UK temperature may rise by 2-3.5ºC by 2080. This does not mean we will all have better weather, as global warming can cause many climate changes:

• Temperature change: some areas may get warmer, others colder.
• Flooding: oceans expand as they get warmer, which may cause flooding. Millions people's homes could flood regularly. The sea level may rise by 50 cm by 2080.
• Rainfall changes: some areas might become wetter, such as North America and South East Asia. Some areas might become drier, such as Africa and India.
• Plant life: some areas might be able to grow better or different crops. Others may not be able to grow crops at all.

Is our increased production of carbon dioxide really causing global warming? Not all scientist agree.

GUESS WHAT?

If we had no atmosphere, Earth temperatures would be about 33ºC lower.