GOULBURN, Australia - As Australian farmer Philip Bell coaxed his cattle along the road, a bystander nodded toward a straggler ambling behind the rest of the herd searching for an overlooked tussock of grass.

"Not much of a bull, is he?" the local said, prompting a rueful smile from beneath Bell's oversized Akubra hat.

"Nah," the cattleman replied. "Used to be, but. He should be 600-700 kilos (1,300-1,550 pounds) but he's nearer 400 now."

As the world's top climate change experts meet in Bangkok to thrash out a long-term response to global warming, farmers in this part of Australia are already in the front line.

Bell's property lies in some of Australia's most fertile agricultural land around Goulburn, some 210 kilometres (130 miles) southwest of Sydney.

However, many of his cattle have been left emaciated by the country's worst drought in a century, a prolonged dry spell Australia's most eminent scientist has linked to climate change.

Environmental researcher Tim Flannery has warned that Brisbane and Adelaide -- home to a combined total of three million people -- could run out of water by year's end.

He said the country was facing a "catastrophic" situation.

"Even a year ago this would have been unthinkable," Flannery told AFP. "I think it's the most extreme and the most dangerous situation arising from climate change facing any country in the world right now."

The drought has forced Bell to "drove," or walk, his hungry cattle in the hope they can get some nutrients from the grass verges along a local back road before being penned into another threadbare paddock.

"We're just trying to find some food for them. We've run out of feed at home and we're just using the road as a break measure because we can't get grain or feed at the moment," he told AFP.

But there are slim pickings as other farmers have been forced to take the same measures in a bid to fatten up their cattle as winter approaches.

"As the weather cools down it's going to get pretty critical," Bell said.

Nearby Goulburn has been on level-five water restrictions, the toughest that can be imposed by authorities in Australia, for two and a half years.

The town's 25,000 inhabitants cannot use outside taps for any reason, including washing cars and watering gardens. Households are limited to 150 litres (33 gallons) of water a day -- about the amount used during a 15-minute shower.

Goulburn's main water supply, the Pejar Dam, has dwindled to only three percent of capacity, despite a sprinkling of rain in recent weeks.

Locals say the parched earth simply soaked up the brief downfall, pointing out that months of heavy rain are needed to top up water storages, rather than the occasional day every few weeks.

"We've had little breaks but it's not enough," farmer John Hoskins said.

Hoskins said the drought that has stretched for a decade in areas of the Murray-Darling Basin, Australia's largest river system, was taking a financial and mental toll on those living off the land.

"The suicide rate in farmers has gone right up," he said. "You've got to keep yourself in tune with your neighbours and not get too isolated and talk to each other if you've got problems.

"Everyone's in the same boat out here, we're all struggling."

The chief executive of an independent think-tank, the Climate Institute, said climate change would make Australia's weather more extreme.

"We'll have intensified cycles so that our droughts will be worse, they'll be more frequent and when it rains it will be more intense as well," John Connor told AFP.

"So it's true that we do have cycles here but some of those cycles are going to get worse and worse."

The government last month said the drought was so severe that it would take the unprecedented step of cutting off irrigation water to the Murray-Darling by July unless the situation improved.

Hoskins said some struggling country people resented the profligacy of their city cousins with water.

"A lot of people expect water down there no matter what. They're happy to flush stuff down the sink and not be responsible for it," he said.

Meanwhile, many farmers faced going to the wall because of a drought that "just keeps rolling on."

"That's the issue," he said. "It's longer than the others.... The difference with this one is it's persisting and just won't seem to go away.

"Before, (with a drought of) two years, we could cope and then, odds on, think that we were going to get out of it.

"At the moment it just keeps rolling on -- that's a bit of a worry."