Climate change is a global issue that affects us all. Changes in climate patterns mean that extreme weather events such as heat waves, floods, storms, droughts and bushfires will become more frequent, more widespread or more intense

WHAT CAUSES CLIMATE CHANGE?
Climate change is the result of changes in our weather patterns because of an increase in the Earth’s average temperature. This is caused by increases in greenhouse gases in the Earth’s atmosphere. These gases soak up heat from the sun but instead of the heat leaving the Earth’s atmosphere, some of it is trapped, making the Earth warmer.

Climate change is also known as global warming.

There are also manufactured gases such as chlorofluorocarbons (CFCs), halocarbons and some of their replacements.

Greenhouse gases are produced by human activity, including:

• burning fossil fuels, such as coal, oil or gas
• using energy generated by burning fossil fuels
• some aspects of farming, such as raising cattle and sheep, using fertilisers and growing some crops
• clearing land, including logging
• breakdown of food and plant wastes and sewerage
• some industrial processes, such as making cement and aluminium.

Water vapour is also a powerful greenhouse gas but the amount in the atmosphere is not directly linked to human activity.

THE GREENHOUSE EFFECT
Greenhouse gases have always been a natural part of the atmosphere. They absorb and re-radiate the sun's warmth and maintain the Earth's temperature at a level necessary to support life.

The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere (water vapor, carbon dioxide, nitrous oxide, and methane, for example) trap energy from the sun.

The problem we now face is that human actions are increasing the amount of the gases that trap heat. This is the enhanced greenhouse effect, which is contributing to a warming of the Earth's surface.

What happens when you go into a greenhouse on a sunny day? It's hot, isn't it? That's because the glass in the greenhouse traps the heat from the sun. This gas carbon dioxide does the same in the earth's atmosphere. It acts like glass in a greenhouse, doing the same’).

THE IMPACTS OF CLIMATE CHANGE:

More hot days: The CSIRO predicts that by 2070, the average temperature in Victoria will rise by between 0.7 and 5ºC above the level measured in the 1990’s. As a general trend, the frequency of days over 35ºC will increase. In some areas this could be by up to three times as much. By 2070, for example:

• Melbourne will experience an increase in the number of extremely hot days from 8 per year to as many as 20
• Wangaratta will move from 15 to as many as 56 days.

Less rain: Victoria can expect less rainfall with climate change. In combination with higher temperatures, this means drier conditions. Studies predict:

• Stream flows in the Murray Darling Basin will decrease by 12 to 25 percent
• Melbourne’s water supply will decrease by between 7 to 35 percent.

More bushfires: In some regions, the risk of bushfire is likely to increase by up to 60% by 2050.

Less snow: Victoria’s alpine areas may have between 18 to 60 percent less natural snow cover by 2020.

Threatened natural environment: The Australian landscape will be changed forever. In your lifetime, you could see damage such as:

• 58 to 81 percent of the Great Barrier Reef bleached
• 40 percent of core habitat for eucalyptus species destroyed
• 80 percent of freshwater wetlands in Kakadu eliminated.

Shifting coastlines: Sea levels are predicted to rise by between 7 and 49 centimeters by 2070. Erosion along our coastline will continue to increase each year as floods arrive more frequently.

Higher insurance: As the weather becomes less predictable and extreme events more likely, the cost of global insurance premiums will increase.