Natural Climate Changes
The world's climate has been changing since the beginning of time. It never stays the same. Some climate changes are natural. Natural climate changes are gradual processes and can often take many hundreds of years to notice.
The most significant and well-known climatic changes have been the Ice Ages. During an Ice Age the weather becomes so cold that most of the water on Earth begins to freeze and form massive ice sheets. The last Ice Age experienced on Earth ended about 10 000 years ago. It created an ice sheet that covered almost one-third of the Earth. The sheet was approximately 240 metres thick.
The world's climate has been changing since the beginning of time. It never stays the same. Some climate changes are natural. Natural climate changes are gradual processes and can often take many hundreds of years to notice.
The most significant and well-known climatic changes have been the Ice Ages. During an Ice Age the weather becomes so cold that most of the water on Earth begins to freeze and form massive ice sheets. The last Ice Age experienced on Earth ended about 10 000 years ago. It created an ice sheet that covered almost one-third of the Earth. The sheet was approximately 240 metres thick.
Climate Change in Australia
Australia has not avoided significant climatic changes. Many thousands of years ago Australia looked very different, especially central Australia which today is very dry. Approximately 15-20 million years ago, in prehistoric times, rainforests were thought to cover all of the Australian landscape. Weather and climate during this time would have been wetter than it is today, as more moisture would have been released by plants and held in the land. Scientists believe that as rainfalls decreased lakes and rivers slowly began to dry out, leading to the drier environment that we know today.
Nature is able to tell us a lot about the climates of the past. Tree trunks, when cut in half, have many rings inside which signify different periods. Rings that are very close together mean that the period of time was very cold, whilst rings that are far apart mean the climate was warmer.
The discovery of dinosaur bones has shown scientists and archaeologists that they could possibly have been killed off due to great climatic changes. Some dinosaurs have even been found in their original condition frozen in ice.
Australia has not avoided significant climatic changes. Many thousands of years ago Australia looked very different, especially central Australia which today is very dry. Approximately 15-20 million years ago, in prehistoric times, rainforests were thought to cover all of the Australian landscape. Weather and climate during this time would have been wetter than it is today, as more moisture would have been released by plants and held in the land. Scientists believe that as rainfalls decreased lakes and rivers slowly began to dry out, leading to the drier environment that we know today.
Nature is able to tell us a lot about the climates of the past. Tree trunks, when cut in half, have many rings inside which signify different periods. Rings that are very close together mean that the period of time was very cold, whilst rings that are far apart mean the climate was warmer.
The discovery of dinosaur bones has shown scientists and archaeologists that they could possibly have been killed off due to great climatic changes. Some dinosaurs have even been found in their original condition frozen in ice.
Droughts
Droughts occur when an area receives less rain than normal. This rain shortage must occur over a length of time for a drought to be declared. Droughts can have devastating consequences, especially on crops, plants and animals, which can all die in drought conditions. Creeks and lakes can also dry up, cutting off water supplies to people and other living things.
The Federation Drought
Australia often experiences droughts due to its naturally dry landscape. Australia's worst recorded drought occurred during 1895-1903. This drought was named the Federation Drought and had devastating consequences for farmers, especially sheep and cattle farmers. Approximately 40 percent of Australia's cattle population were killed, whilst half of the sheep population died.
Droughts are difficult to predict but they have often been linked to the climatic phenomenon called El Nino (see left).
Droughts are difficult to predict but they have often been linked to the climatic phenomenon called El Nino (see left).
Floods
Floods occur after extremely high levels of rain falls to earth. Heavy rains may strain the Earth's natural and unnatural water processing systems (ground absorption, street drains). There are three types of floods: river floods; flash floods; and flooding in mountainous regions.
Australia is also susceptible to floods which are often linked to the La Nina effect (see above movie). There have been many devastating floods in Australia which have seen rivers burst, cities and towns under water and crops ruined due to the high amounts of water.
Australia is also susceptible to floods which are often linked to the La Nina effect (see above movie). There have been many devastating floods in Australia which have seen rivers burst, cities and towns under water and crops ruined due to the high amounts of water.