Today's scientists talk in terms of the continents large climate variability from season to season, and from year to year. The impact of climate variability on Australia was highlighted by events during the early 1990s. In 1990-91 the wet season produced abundant rains, yet it failed almost completely the following year as drought set in across Queensland and New South Wales. While drought continued in some areas through 1992 and 1993, many people in southeast Australia will long remember the floods of spring 1992 and spring 1993, and the cool summers which followed. Rural productivity, especially in Queensland and New South Wales, is linked to the behaviour of the Southern Oscillation.
Tourism is another industry vulnerable to large swings in seasonal climate.
Because climate variability can affect the Australian economy, Australians need the best possible understanding of the physical mechanisms controlling this dramatic feature of their climate. Characteristic changes in the atmosphere accompany those in the ocean, resulting in altered weather patterns across the globe. The Pacific Ocean is a huge mass of water which controls many climate features in its region. In most years the Humboldt current brings relatively cold water northward along the west coast of South America, an effect increased by upwelling of cold water along the Peruvian Coast. The cold water then flows westward along the equator and is heated by the tropical sun.