Australia has water troubles.

For at least the past nine years, the people "down under" have been experiencing perhaps the worst drought of their history, the "Big Dry," as they're calling it.

The drop in rainfall and river flows has been most severe in the southern and eastern states (Victoria, New South Wales, South Australia, and parts of Queensland), which happen to house the majority of Australians and also the country's major agricultural centers. Dry days—dry decades, in fact—are also dogging Western Australia's major city, Perth.

Australia, with its approximately 22 million people, has by some estimates the planet's 15th largest economy. But the current drought has abruptly reminded Australians of the limits that natural resources and climate place on human activity.

Although rains this past winter have done their part to mitigate the worst of the drought, over the last decade city residents have been placed on stringent water-use restrictions in an effort to reduce daily consumption: gardens have gone unwatered and people showered with buckets to catch the water for other uses.

Even with the strictest of limitations in place, the threat that the water could run out confronted each of Australia's cities. In 2007, word in Brisbane was that without sufficient rain, the city would run dry in 2009. The same year, the people of Adelaide were told that "critical human needs" might not be met in the future.

To make matters worse, thirsty animals have been barging their way into human settlements. Snake bites are on the rise in Victoria and New South Wales as venomous snakes across southeastern Australia have slithered to urban areas in search of water. In November 2009, about 6,000 camels overran the outback town of Docker River in the Northern Territory (pop. 350) in search of water, head-butting water tanks, trampling fences, and licking water from air conditioning units.

If the urban areas have found their lifestyles cramped, the agricultural sector has been devastated by the drought. Irrigation farmers who specialize in "thirsty" but highly profitable crops like rice and cotton have been especially hard hit.

By 2008, rice growing came to a standstill, falling 98% across the country. The rice mill in Deniliquin (New South Wales), which alone used to produce rice for as many as 20 million people around the world, shut its doors. The result was a global shortage, with world rice prices doubling and violent food protests erupting across the globe.

Pastoral livestock farmers have also suffered. "I can't stand lying in bed every night and hearing the cattle bellow from hunger," lamented dairy farmer Malcolm Adlington in 2009 to a National Geographic reporter.

Not long ago, Anna Creek in South Australia was home to the planet's largest cattle station—24,000 square kilometers, larger than Israel—but now there are few cattle left. Most have been sold off, but carcasses of the less fortunate dot the landscape.

And the price tag for this agricultural breakdown has been high for the Australian government: several billon dollars in drought relief to rural areas since 2001.

To make matters worse, Australia's fragile ecosystems are also in crisis. The most important river system, the Murray-Darling Basin (MDB), is suffering severe environmental distress. The Basin covers 14% of Australia and produces 40-45% of all of Australia's agriculture (A$14 billion/year).

All through the catchment, wetlands have disappeared to disastrous results. Today, 75% of the long-lived, majestic River Red Gum trees are considered dying or stressed, and the birds and fish that relied on the river's water to breed are failing.

In recent years, as more and more water has been diverted for human usage, the Murray has dried up before reaching the sea. The extreme drop in fresh water has raised the salinity levels of the vibrant coastal ecosystem known as the Coorong and two nearby lakes, Albert and Alexandrina. Wholesale changes in flora and fauna are underway and, in the case of Albert, the receding water has exposed acid sulphate soils to the air producing poisonous sulfuric acid across large segments of the dry lakebed.