How Climate Has Shaped Australia
Australia’s annual rainfall is very variable, partly due to the effects of a weather phenomenon called the Southern Oscillation, including “El Niño”, which causes major variations in ocean temperatures. In “normal” years, i.e. when El Niño is not a factor, the surface temperature of the western Pacific Ocean to the north/northeast of Australia is up to 10 degrees warmer than the eastern Pacific. For Australia, this has the effect of causing major droughts in some years and extended wet periods and sometimes tropical cyclones in others. This long term variability in the climate has contributed to the unique evolution of the continent’s flora and fauna.
According to the Australian Government Bureau of Meteorology, “Australia's climate is dominated by the dry, sinking air of the subtropical high pressure belt which moves north and south with the seasons”. Not only does this cause Australia’s rainfall to vary with the seasons of the year, but it also contributes to the definition of the major climatic regions” Additionally, it creates a wide range of environments across the country, which covers a total area of almost 3 million square miles and overall is the world’s second driest continent.
The tropical regions in the northern parts of Australia have wet summers (October to April) due to the monsoons. During this season – colloquially called “the wet” – humid conditions with showers and thunderstorms come through on the moist northwesterly winds. In contrast, the winter conditions are typically mild and dry with blue skies. In the dry, inland areas of this tropical region of Australia, the main form of agriculture is pastoralism, adapted to cope with the typically harsh climate.
Southern Australia experiences dry, hot summers that can trigger bush fires aided by the hot winds from the interior. In winter, rainfall brought in by westerly winds and cold fronts provides the needed water for much of Australia’s crop production. Although temperatures in the coastal areas are mild year round, frosts can occur inland.
Works Cited
Australian Government Bureau of Meteorology. Climate Education. Australia – Climate of Our Continent. Retrieved from http://www.bom.gov.au/lam/climate/levelthree/ausclim/zones.htm#one
Australian Government Bureau of Meteorology. Climate Variability and El Niño. Retrieved from http://www.bom.gov.au/climate/glossary/elnino/elnino.shtml
