Global Warming

Global Warming

Global warming is issue that is becoming increasingly prevalent in today's society. Awareness of its possible implications and its frightening growth rate have reached a point where global warming has caused many changes in the way we live. Efforts to combat global warming have taken place on all levels of society. Individuals attempt to reduce their energy consumption, corporations implement company wide guidelines to help reduce greenhouse gases and countries have combined together to analyze this issue and develop a plan of action.

The term "global warming", is used to describe the average increase in the Earths atmospheric temperature due to human activity. According to the UNFCC (United Nations Framework Convention on Climate Change):

"The principal reason for the mounting thermometer is a century and a half of industrialization: the burning of ever-greater quantities of oil, gasoline, and coal, the cutting of forests, and the practice of certain farming methods."

What this industrialization has done has increased the amount of "greenhouse" gases in Earth's atmosphere, will the burning of fossil fuels being cited as the number one source of these gases.

Greenhouse gases are gases such as water vapour, carbon dioxide, methane, nitrous oxide, and ozone. These are gases that occur naturally and essential for life. Apart from their other functions, they also function to create a blanket around the Earth to keep Earth at a habitable temperature. The picture below shows how greenhouses gases work to heat the Earth:

Without these gases, the surface and atmospheric temperate of Earth would be much lower. The current average surface temperate on Earth is around 14-15Ð'oC, without these gases, the surface temperature would be closer to -18Ð'oC (CSIRO Marine and Atmospheric Research, 2003). Unfortunately the amounts of greenhouses gases in our atmosphere has increased in last 150 years, causing an increase of 0.6Ð'oC in the average temperate on Earth and is expected to climb by another 1.4Ð'oC to 5.8Ð'oC by the year 2100 (UNFCC, 2006). This artificial increase of greenhouses gases has caused changes in our climate and also has other effects on our planet.

The runaway greenhouse effect is what we call a "positive feedback loop". It is almost like a chain reaction. It is when the increase in temperate increases the greenhouse effect, and in turn, the greenhouse effect increases temperate. What it does is create a dangerous cycle that builds upon its self, or accelerates. Water vapour tends to be the most commonly cited example of how this runaway effect could occur, for example: A change in Earth's surface temperature of 1 degree causes an increase in water vapour (melting of ice, more water is evaporated etc..) by X amount. This increase in water vapour then in turn increases the Earth's surface temperature, because as we know, water vapour is a greenhouse gas. There are several different possible combinations and models of this runaway effect; it is not limited to water vapour only.

As you can see, there is a difference between an enhanced or increased greenhouse effect and the runaway greenhouse effect. One is fundamentally linear, while the other is an accelerating function. Unfortunately, according to World Press (2004), scientists have indicated that the runaway greenhouse effect is already underway on Earth. Recent findings have shown that "the greenhouse gas emission reduction targets established in the 1997 Kyoto agreement do not go far enough and far more radical solutions must be found" . The rate of melting in some ice bergs is double of what is was in the early 1990's. The runaway effect can have a devastating effect on a planet if it not stopped. Ultimately, the runaway greenhouse effect would destroy life and any potential for life, similar to the planet Venus. According to the UNFCC, although this ultimatum may be a long time away from happening, there are more immediate effects that have already been observed on Earth. If this runaway effect continues on Earth, ocean levels will rise and storms will increase in intensity and frequency. The UNFCC has stated that "Recent severe storms, floods, and droughts, for example, appear to show that computer models predicting more frequent "extreme weather events" are on target" . The average sea level rose by 10-20 cm in the 20th century and this poses a threat to the heavily populated coastlines and island of the world and threatens to spoil large sources of fresh water (UNFCC, 2006). Other impacts of the runaway greenhouse effect are the damage to animal and plant life (UNFCC predicts that some 25 per cent of mammals and 12 per cent of birds may become extinct within 100 years or less), shorter winters, and increased frequency of diseases. Needless to say that while it may be fascinating to study the results of the runaway greenhouse effect on planets like Venus, it is an immediate threat to Earth that must be address swiftly and effectively.

Scientists believe that Venus is a victim of the runaway greenhouse effect and that Venus shows what the possible implications of a runaway effect on Earth could be. Studies have suggested that Venus was very similar to Earth several billion years ago, including substantial quantities of liquid surface water (Space.com, 2004). Suffering from the runaway greenhouse effect for billions of years has left Venus a hostile planet with an atmospheric pressure 90 times that of Earth's and an average surface temperate of 400Ð'oC. It is believed that the runaway greenhouse effect on Venus was caused by the evaporation of surface water which eventually boiled away all the oceans on Venus and created the climate conditions that exist today. Unfortunately for Venus, it would seem that there is no hope. It would be a monumental task to reverse the effects of the runaway greenhouse effect on Venus, and it would most likely have to happen in way beyond the power of humans. There has been some hypothetical discussion that if the greenhouse effect becomes too strong, enough heat may not make it through the planet's atmosphere and the planet would begin to cool. What would most likely happen in this case is that the greenhouse effect would decrease until a point where temperate could be maintained, which would most likely still be considered an extreme level. Another possibility is that of an asteroid impacting with Venus and essentially "blowing away" its atmosphere. This could possibly reduce the greenhouse effect, but would most likely not restore it to