Government study: Climate change boosted 'unprecedented' drought

An Australian government study published Friday claims to establish a direct cause-and-effect relationship between man-made climate change and the country's recently ended decade of "unprecedented" drought.

While the study establishes a link between climate change and drought, authors of the South Eastern Australian Climate Initiative's synthesis report (PDF) said the changes forecast by their research point to weather systems becoming much more erratic and rainfall scarce across south-eastern Australia as the average annual temperature rises.

The study began with urgency in 2006, amid Australia's so-called Millennium Drought, which got underway in 2001 and didn't abate until 2010, then the country saw record rains a major typhoon that brought devastating floods. They added that the Millennium Drought was "unprecedented" in the country's history, far outstripping the two worst droughts that preceded it, and even appeared to exceed previously observed "natural variability" observed in historical records. That could indicate "a shift in the climate 'baseline,'" they warned.

Researchers said that it is possible some of the flooding in 2010 and 2011 was attributable to climate change as well, with drought-hardened ground contributing to greater water runoff and the warmest ocean temperatures on record supercharging major storms. "This is particularly true in the northern part of [Australia's major river network] the Murray–Darling Basin where it is estimated that elevated sea-surface temperatures may have contributed 10 to 25 percent of the total rainfall," they wrote.

Despite record rains last year, south-eastern Australia experienced its fifth hottest month on record in August, and many forecasts are pointing to another severe drought on the horizon.

"Climate change projections show a wide range of possible and plausible impacts, and there is therefore a high degree of uncertainty about future rainfall and streamflow scenarios," researchers concluded. "This means water resource managers need to ensure that their planning and management processes are robust and adaptive across a wide range of future climate and streamflow scenarios and are subject to regular review."

The United Nations' Intergovernmental Panel on Climate Change has long maintained that climate change can produce extreme weather, but they've tended to look for links in long term shifts in average temperatures rather than direct climate links to specific incidents.

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