Australia
Missing : enough water to fill Sydney Harbour 90 times over

Satellites have been used to map Australia’s fresh water for the first time, and the picture is bleak.

In just three years, the continent has suffered a net loss of 46 cubic kilometers of fresh water - enough to fill Sydney Harbour more than 90 times.

Initial results of the international satellite project provide another indication Australia is drying out.

Based on current consumption patterns of about 1.5 billion litres a day, the water lost could have quenched Sydney’s thirst for more than 80 years.

The discovery has been made using two US and German satellites designed to map all the world’s water stocks - a task never before possible.

Launched by a Russian rocket in 2002, Grace, the Gravity Recovery and Climate Experiment, involves two identical craft circling 220km apart, 485km up. By repeatedly plotting variations in the tug of earth’s gravity, Grace can estimate changes in the mass of the water below. It also measures water in river basins and reservoirs.

Key findings will not be published until next year, but professor Jay Famiglietti, a hydrologist at the University of California, Irvine, calculated the overall decline observed in Australia’s fresh water.

Between February 2003 and January this year, Australia lost 46 cubic kilometers. But it would take a further five years of mapping before his team could say whether Australia’s drying was a short term variation from drought, or a long term trend triggered by climate change.

“Some continents have increasing water storage - for example North America,” Famiglietti said. “The global result will be interesting.”

- Sydney Morning Herald