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In the late 1990s, winemaker Rick Kinzbrunner first noticed changes in weather patterns at his Giaconda vineyard in the southern Australian state of Victoria. His Pinot Noir vines – the grape with the greatest sensitivity to temperature – were ripening earlier, creating a host of problems, notably unacceptably high alcohol levels.

When continuing warm weather in the current decade pointed to a long-term shift in the climate, Mr Kinzbrunner opted for radical action. He shifted plantings to higher altitudes, grafted over much of his Pinot to Chardonnay, increased production of Shiraz, and began to experiment with other grapes that favour warmer temperatures such as Nebbiolo, the Italian variety.

“[The changes] have served us very well,” Mr Kinzbrunner says. “We have been able to maintain the quality of our Chardonnay, which is the most important for us.”

Two severe droughts since the turn of the century, coupled with greater environmental awareness across the globe, have put climate change on Australia’s national agenda like never before.

Extremely dry weather in Australia is nothing new. A century ago, the country suffered a period of weather similar in severity to that of recent years – the so-called “Federation Drought”, so-named because it coincided with the formation of Australia and independence from Britain in 1901.

“Australia has naturally occurring drought cycles,” says Matthew England, co-director of the Climate Change Research Centre at the University of New South Wales. “The recent droughts in eastern Australia are probably almost entirely due to natural variability. But droughts in future will tend to be more and more severe.”

Already the world’s driest inhabited continent, few parts of Australia are set to be net beneficiaries of climate change – in contrast to areas of northern Europe, for example.

“There are great vulnerabilities in Australia,” says David Karoly, a professor in earth sciences at Melbourne University. “Some assessments suggest that this economy and society are more vulnerable to climate change than any other developed country in the world.”

Moreover, because it is a key global agricultural producer, climate change in Australia will have broad ramifications. Australia is the world’s largest exporter of wool and among the top three exporters of beef, lamb, wheat and sugar. Although agriculture accounts for only 2 per cent of the country’s gross domestic product, it constitutes about 18 per cent of total merchandise exports, with about two-thirds of Australia’s agricultural production sold on international markets.

On average, Australian temperatures have increased 0.9°C since 1950, according to the Bureau of Meteorology and the Commonwealth Scientific and Industrial Research Organisation. But there has been considerable regional variation, with average temperatures rising more in some parts of the country. The warmest years have mainly occurred recently, the highest average coming in 2005.

As for rainfall, the east coast, Victoria and south-west Australia have experienced sharp declines since 1950, while north-west Australia has seen increased rainfall in the same period.

Agriculture has suffered. “Some of the parts of Australia most severely affected just happen to be where people live and where we get most of our food from,” says Michael Coughlan, chief climatologist at the National Climate Centre’s Bureau of Meterology.

The Murray-Darling Basin has emerged as a critical concern. The basin, which extends 3,400km and covers New South Wales, southern Queensland, Victoria and the eastern tip of South Australia, contains 42 per cent of Australia’s farmland. It is farmland that has always been heavily dependent on irrigation, yet Australia’s biggest cities also rely on the river system for water supplies.

After the three warmest years on record in the basin, storage and inflow levels are at record lows. In addition, the falling water levels are exposing more soil to the air, in turn accelerating the release of sulphuric acid, which is further damaging an already fragile ecosystem.

Recent research by Csiro, Australia’s national science agency, has shown that a rise of 1°C in the basin’s air temperature leads to a 4 per cent increase in evaporation and a reduction of inflows of about 15 per cent.

This has potentially serious implications, given that Csiro and the BoM expect average temperatures in Australia to rise by as much as 5°C by 2070, compared with 1990, with warming likely to be greatest in inland areas.

Rainfall in southern areas is also expected to decrease about 10 per cent by 2070, relative to 1990, but some regions will suffer far greater changes. The south-west could experience a decrease in rainfall of up to 40 per cent in winter and spring by 2070.

In addition, extreme events are projected to increase in frequency and severity – a reality underlined by the droughts of the past decade. The BoM/Csiro models suggest there will be up to 20 per cent more drought months across most of Australia by 2030.

The knock-on impact on agriculture could be severe. Economist William Cline has estimated that Australian agricultural productivity could fall 27 per cent by 2080.

Modelling by the Australian Bureau of Agricultural and Resource Economics, the commodities forecasting agency, suggests Australian wheat production could fall 13 per cent by 2050, relative to 1990 – and to expected output levels without climate change. Beef production could fall 19 per cent, sheep meat 14 per cent and dairy 18 per cent.

But the Abare projections do not include provision for mitigating action – such as that taken by Mr Kinzbrunner. Helal Ahammad, head of Abare’s climate change analysis branch, says there is considerable scope for such activities.

“Australian farmers have been adapting to seasonal variation and international competitive pressure. Climate change poses an additional challenge to which farmers will respond via innovation and increased productivity,” he says.

Australia also has the added responsibility of being the country in the southern hemisphere with the greatest climate change capability, says Prof Karoly. Among the differences in the hemisphere are the lack of significant sea ice retreat in Antarctica, in contrast to the Arctic, and the recovery in the Antarctic’s ozone layer. The latter could encourage greater rainfall in the southern hemisphere.

“This is a miniscule development internationally,” he says, “but it is critical for Australia.”

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