What Is Climate Change?
"Probably, long-term, the single most important issue we face as a global community" (Tony Blair, the UK Prime Minister).
"If we don't do something now to tackle climate change we're doomed. I don't want that on my conscience, do you?" (Tim Wheeler, lead singer, Ash)
"Recent dramatic weather events such as the floods in Carlisle and Boscastle are a stark reminder that nature can only take so much. Climate change is a reality and we must act now if we are to stop the damage we are doing to our fragile planet" (Sian Lloyd, TV Weather reporter)
The term Climate Change refers to changes in the Earth's climate i.e. it's weather systems, rainfall and temperatures. These changes can be caused naturally either, as a result of changes in the way oceans and the atmosphere interact, or from changes in the amount of energy received from the sun.
However, human activities that are increasing the emissions of greenhouse gases such as carbon dioxide and methane may also be speeding up Climate Change. Understanding the 'Greenhouse Effect' is key to understanding the term Climate Change.
The Greenhouse Effect
[Illustration showing how gas molecules trap solar radiation in the Earth's atmosphere provided by Manitoba Energy, Science and Technology, Climate Change Branch]
The Earth's surface is warmed by solar radiation which beats down on the Earth from the Sun. Most solar raidation is reflected from the Earth's surface back into space, but in the atmsophere are a number of gases that can absorb the outgoing solar radiation and trap some of the refelcted solar heat in the Earth's atmosphere. This process naturally keeps the Earth at a steady temperature, by trapping heat in but allowing the majority of the reflected solar radiation to pass back out into space. Without this trapping effect the planet would be too cold for life as we know it. It is important for life on Earth that this fine balance between the amount of solar radiation absorbed by the surface and in the atmsophere and that reflected back into space remains relatively constant. Any increase in the concentration of particular gases in the atmosphere can prevent heat from being radiated out into space and upset this fine balance, trapping more radiation in the atmosphere and reflecting it back to the lower layers of the atmosphere 
closer to the surface, thus raising the world's temperature.
This trapping and reflection of radiation is known as the Greenhouse Effect, as it is essentially the same process that warms the air in the greenhouse in your garden.
One of the results of the global 'Greenhouse Effect' is the heating up the earth's surface, oceans and atmosphere.
Scientists believe that the Greenhouse Effect is already occuring as historical records show that global temperatures are rising, polar snow caps are retreating and sea levels are rising. A rise in temperature of just one or two degrees will result in changing weather patterns and lead to increased flooding, desertification, crop failures, freshwater shortages and storms.
Carbon dioxide is the main gas that is accountable for the Greenhouse Effect. About 6.5 billion tonnes of carbon dioxide are emitted globally each year, mostly through burning coal, oil and gas during industrial, domestic, transport and agricultural processes. At present there is no technology that will prevent the release of carbon dioxide, although there are some that reduce the amount of gas being released. Other greenhouse gases also have an effect, such as methane, nitrous oxide and aerosol gases like hydroflourocarbons, but carbon dioxide emissions from energy use are widely accepted as the largest contributor to global warming.
How are greenhouse gases being released?
Fuels such as oil and coal were formed 300-350 million years ago from the remains of plants and animals. Deposits of silt covered this organic material. As the organic material began to decompose and compress, huge deposits of fossil fuels were formed. The silt deposits covering the organic material prevented natural gases such as sulphur dioxide, nitrogen oxides and carbon dioxide from being released into the atmosphere. Instead it was trapped in a solid (coal), liquid (oil) and gas (natural gas) form.
By burning these fuels now to produce power the gases which had been trapped are released into the atmosphere, adding to the natural carbon dioxide in the atmosphere. Our whole way of modern living demands power, and ultimately it is this power demand, driven by fossil fuel burning, which is threatening increasing climate change effects in the Earth's atmosphere.
(Image © Research Machines plc)
What is being done about it?
The Kyoto Protocol is an international agreement that commits the world's industrialised countries to specific targets for reducing their greenhouse gas emissions. The Protocol came into force in 2005 when Russia became the 128th nation to ratify it and in doing so ensured that the agreement bound nations whose combined emissions accounted for 55% of the world's total greenhouse gas emissions to emission reductions.
The protocol suffered a huge blow when the USA - responsible for a quarter of global emissions - pulled out in 2001. The USA, China, Australia, India, Japan and South Korea have declared their intention not to ratify the Protocol. Instead they have signed up to a separate agreement, the Asia-Pacific Partnership on Clean Development. This pact focuses on technology transfer to reduce emissions and does not set targets for individual countries.