Aussie farms face 'disruption and decline'

Australia's agricultural production will face "disruption and decline" as hotter and drier conditions stress rural communities in parts of the country, an Intergovernmental Panel on Climate Change report has found.

The new IPCC report delivers perhaps the most damning summary yet of the impact of human-induced climate change and the need for urgent action to address it.

In Australia, the accumulated productivity losses across agriculture, manufacturing and service sectors could exceed $4 trillion by 2100 under a high emissions environment.

Australian crop yields are forecast to decline in parts of Australia's south and east, while some rural communities in those areas will face increased stress due to the forecast hotter and drier conditions.

Mark Howden, vice-chair of the working group which compiled the report, said climate change was challenging Australia's agricultural productivity.

"We're already seeing a big drag on our productivity from climate change and that is likely to continue into the future," said Prof Howden, from the Australian National University.

He said technological improvements had helped farm profitability in the face of more difficult conditions.

Prof Howden said that as conditions get hotter, the window to grow crops would contract, while livestock would face increased heat stress.

"We're likely to see those negative impacts accelerate as climate change progresses and that means we have to be even smarter in how we farm in an even more variable environment," he told AAP.

Lead author of the Australasia chapter of the IPCC report, Francis Chiew, said that in a 2C warmer world, the Murray-Darling Basin would be compromised.

"If you have 20 per cent less water you have challenges in how you'll adapt, and how you might share water between competing demands which is already a very significant problem," said Dr Chiew, a senior hydrologist at Australia's science agency CSIRO.

"If you have less water you grow less food ... although agriculture has also been adapting really well," he told AAP.

Agriculture Minister David Littleproud told AAP that the government had already helped farmers and regional communities to adapt to the changing climate.

"There is support, research and innovations for farmers and farming communities to make their land more productive, diversify their income and become more resilient to the impacts of climate change."

Among the government's initiatives is a $5 billion Future Drought Fund to help farmers and communities.