During climate extremes, whether droughts or flooding rains, those on the land feel it most. Agriculture suffers first and most severely - yet eventually everyone feels the impact.

Drought disrupts cropping programs, reduces breeding stock, and threatens permanent erosion of the capital and resource base of farming enterprises. Declining productivity affects rural Australia and the national economy.

The risk of serious environmental damage, particularly through vegetation loss and soil erosion, has long term implications for the sustainability of our agricultural industries. Water quality suffers, and toxic algae outbreaks may occur; plants and animals are also threatened. Bushfires and duststorms often increase during dry times.

Its causes?

Australia has one of the most variable rainfall climates in the world. Over the long term we have about three good years and three bad years out of ten. These fluctuations have many causes, but the strongest is the climate phenomenon called the Southern Oscillation.

For Australian conditions, drought frequency is crucial. Research indicates that severe drought affects some part of Australia about once every 18 years. This does not indicate that severe drought regularly and predictably recurs every 18 years; intervals between severe droughts have varied from four to 38 years. We have long historical rainfall records to give a clearer picture of what is 'normal' for an area, and how much variation might be expected.

There is little chance that all Australia could be in drought at the same time. Some droughts are long-lived; some are short and intense, causing significant damage. Some can be localised while other parts of the country enjoy bountiful rain. Some regional droughts are not related to El Niño events, and are therefore harder to forecast. Examples of each of these types of drought are shown in the large picture below.

Global monitoring

Meteorologists need up-to-date information on global climate patterns for early warning and monitoring of drought. Under the umbrella of the World Meteorological Organization (WMO), the Bureau participates in and contributes to international weather and climate watch programs. The WMO's new Climate Information and Prediction Services (CLIPS) project is designed to enable member nations to make the most of new abilities to monitor and predict seasonal climate variations.