Why - Global Warming
Global warming is a problem which has presented itself over the past 10 to 20 years. It is caused by 'the greenhouse effect'.
The Earth's temperature is determined by the balance of energy entering the atmosphere from the sun in the form of sunlight and the amount of energy lost from the Earth in the form of infrared radiation.
Infrared radiation is partially absorbed by gases in the atmosphere and re-emitted back towards the Earth's surface consequently warming it.
The natural greenhouse effect is actually vital to the Earth, without it the Earth would be around 30°C cooler than it is at the moment, and consequently be uninhabitable.
However the 'greenhouse gases' now not only include Carbon Dioxide (CO2) and methane (CH4), but also newer man-made gases and chemicals such as CFCs (chlorofluorocarbons). As the amount of greenhouse gases in the atmosphere increase, the amount of infrared radiation deflected towards the Earth will also increase which then warms the Earth more and more. This increased warming is causing disastrous effects for example sea levels are rising and polar ice caps are melting.
[Image: Global Warming Diagram]
Due to the Montreal Protocol, greenhouse gases such as CFCs have been all but eliminated. This means that their influence on global warming has decreased. Unfortunately, due to their lifetimes of around 100 years, the concentrations of these gases are only now, slowly beginning to decrease now.
Ozone depleting substances include;
- Chlorofluorocarbons (CFCs)
- Halons
- Carbon tetrachloride
- Hydrobromofluorocarbons (HBFCs)
- Hydrochlorofluorocarbons (HCFCs)
- Methyl Bromide
- Bromochloromethane (BMC)
To save the planet that we live in now, we need to help to lower the emissions of greenhouse gases and ozone depleting substances that are making our planet heat up.
Small changes can make a big difference, whether this is done by walking to school or college, taking the bus instead of going by car or even just turning off a light when leaving a room, see how we did it and more ideas.
- Australian Government. (2007). Ozone depleting substances. Retrieved March 01, 2008, from Department of the Environment, Water, Heritage and the Arts of the Australian Government Web site: http://www.environment.gov.au/atmosphere/ozone/ods/index.html
- Environmental Protection Agency (US). (2007). Ozone Depletion Glossary. Retrieved March 01, 2008, from Environmental Protection Agency Web site: http://www.epa.gov/ozone/defns.html#odp