Climate Change Explained
Climate change (also known as global warming) is caused by an excess of carbon dioxide (CO2) and other greenhouse gases in the earth's atmosphere.
The Greenhouse Effect
Just like wearing layers of clothing trap body heat to keep skiers warm, carbon dioxide and other gases warm the surface of the earth naturally by trapping solar heat in the atmosphere. Without these gases (known as greenhouse gases) the earth would be a frozen wasteland with an average temperature of minus 15 degrees centigrade (the same as the moon).
Too Much of a Good Thing
The problem is, human activities have dramatically increased the amount of carbon dioxide in the earth’s atmosphere and this is causing things to heat up — in the same way as wearing too many layers causes skiers to overheat. Atmospheric carbon dioxide is 30 per cent higher today than in pre-industrial times and is higher than it has been for at least 420,000 years. The result of this excess carbon dioxide is climate change.
The main causes of increasing carbon dioxide concentrations are the burning of fossil fuels — coal, oil, gas — and the clearing of forests. Various industrial, transportation and agricultural activities are also responsible for increases in the atmospheric concentrations of other greenhouse gases, such as methane and nitrous oxide.
Things are Already Hotting Up
The average surface temperature of the earth increased by 0.6 degrees centigrade during the 20th century. 
Nineteen of the 20 hottest years on record have occurred since 1980, the top 10 since 1990.
Most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations. And we are already starting to see the effects of these increased temperatures — Glaciers are melting, plants and animals are being forced from their habitat, and the number of severe storms and droughts is increasing.
And There's More to Come — Unless We Act Now
If climate change continues, we can expect catastrophic consequences:
- Global sea levels could rise by more than 6 metres devastating coastal areas worldwide and affecting millions of people.
- Cyclones, hurricanes and tropical storms will become more intense.
- Hundreds of millions of additional people will be at risk from malaria and billions from water shortage.
- The world’s water management, agriculture and forestry sectors will require additional annual costs in the tens of billions of dollars
- More than half of the world’s coral reefs including The Great Barrier Reef in Australia could be destroyed.
- Heat waves will be more frequent and more intense.
- Droughts and wildfires will occur more often.
- The Arctic Ocean could be ice free in summer by 2050.
- More than a million species worldwide could be driven to extinction by 2050.
- And our ski fields could disappear.
Remember it's not too late to stop this happening. In addition to supporting environmental initiatives, everyone of us can make a difference by living green and encouraging others to do the same.
Further Reading
If you would like to learn more about climate change and its causes as well as what you can do about it, see Climate Change Explained - Further Reading for details on recommended books.