Global warming is the rapid and continued increase of the Earth's surface temperature. During the last century the earth warmed by 0.8°C. Now the Intergovernmental Panel on Climate Change (IPCC) is projecting that global surface temperatures are likely to increase by 1.1 to 6.4 °C this century. Already nineteen of the hottest 20 years on record have occurred since 1980 with 2005 being the hottest year in recorded history while the east coast of Australia had its warmest May on record in 2007.

This warming is attributable to human activities that increase the levels of greenhouse gasses (GHGs) in our atmosphere. A natural amount of GHGs are essential for life on earth, it keeps our planet at just the right temperature by letting sunlight through but retaining only some of the heat. The increased concentration of GHGs in the atmosphere reduces the amount of the sun's warmth that is reflected back into space causing the Earth to become warmer.

The current concentrations of GHGs in the atmosphere are now substantially higher than any time in the last 650,000 years. The increase of GHGs in our atmosphere was kick-started with the industrial revolution, which since the 1850s has largely increased the output of the key GHGs, carbon dioxide, methane and nitrous oxide. At present, atmospheric concentrations of carbon dioxide have increased by over 30% and methane by over 150% above pre-industrial levels and are projected to rise by over 10% every 20 years.

GHGs come from a variety of sources, the burning of fossil fuels from industry and transportation, methane from livestock and paddy rice farming, construction of buildings, the making of cement and deforestation. Three quarters of GHG emissions in the last 20 years have come from fossil fuel burning with the remainder coming largely from deforestation. Aviation is responsible for an estimated 3% of global GHG emissions but is expected to increase in the future.

In today's society, every item we consume is created by an industrial process, and hence has greenhouse gas emissions associated with it. Not just your car and your electricity and gas but everything:

· Your clothes.
· The computer on your desk.
· The furniture on which you sit.
· The food that you eat (unless it was grown, harvested and transported entirely by hand).
· The products you buy.
· The government services you consume (e.g. roads, health services, defence).

The only way to avoid Greenhouse emissions would be to go live in a cave without power or heat (no little camp fires allowed!) and make everything (I mean everything!) by hand; You can't have any livestock either as one tonne of methane contributes to the greenhouse effect as much as 21 tonnes of carbon dioxide!

Living in a cave, while an adventure perhaps, is not exactly plausible. The alternative is to remove the greenhouse gases from the atmosphere in the short term while trusting that, globally, people are working to develop new, more Earth-friendly technologies in the mid to long term.