'Global Warming' is the term given to the aspect of 'Climate Change' which discusses the way in which the Earth's temperature (measured as the temperature of the air near the surface of the earth and of the oceans) has, and is continuing to, increase. The term is generally used when discussing the human race's impact on the environment, which is also indicated by the term 'anthropogenic climate change'.

Over the last century the Earth's temperature rose approximately 0.74°C. To see the difference this small amount can make, please read What Difference Does 1°C Make?. The Intergovernmental Panel on Climate Change (IPCC) concluded that "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations".

These greenhouse gases, trapped within the Earth's atmosphere, cause the surface to warm - hence the term 'greenhouse effect'.

Current predictions by the IPCC forecast that the Earth's surface temperature is likely to increase by 1.1°C between 1990 and 2100. This would bring the temperature to 6.4°C. However, nothing can be accurately predicted, as we can not be sure of the future uses of greenhouse gases, or the exact way the climate will adapt to or accommodate them.

The other danger of carbon dioxide is the lengthy atmospheric lifetime of the gas - meaning that even if emissions suddenly halted, Global warming could continue for more than another millennium. Also, the rate of emissions and the warming of the planet are not inline with each other - our actions now will not impact on the environment immediately, but rather catch up with us later. Meaning things are only going to get worse unless we clean up our act now.

Some studies argue that this general warming of the Earth's surface is due to internal factors and is natural - factors such as variances in solar activity, the Earth's orbit, or volcanic emissions. Another theory is that we are actually coming out of 'The Little Ice Age' - a period of naturally cool temperature, hence the increase. However, studies of the last 50 years where much data is available, points at Human influence, and the emission of greenhouse gases, particularly since the industrial revolution, as the most potent. Our contribution of carbon dioxide to the Ozone layer during the last 20 years is 75% due to burning fossil fuels - the other 25% being due to changes in the use of land, predominantly deforestation. For more information of the serious effects of deforestation, please read The Role of Rainforests.

The current "atmospheric concentration of CO2 is approximately 383 parts per million (ppm) by volume", but whilst this amount is set to rise, actual predictions of by how much vary greatly. One factor which will affect this rise significantly is the availability of fossil fuels and how extensively they are mined.

References: www.wikipedia.org