While the politics of climate change are being played out in Canberra, many of the world's leading botanists are in Melbourne discussing the science of survival for the planet's plant life.

Researchers at the week-long International Botanical Congress warn of implications ranging from the threat to future food supplies from declining agricultural land and potential clashes between farming and crucial ecosystems to impacts on grape-growing for wine.

And as demand grows for new means of feeding a global population expected to reach 9.5 billion this century, scientists worry that funding for agricultural research is falling around the world.

Scientists said cutting-edge technology and genetic modification would not be enough to provide the grains needed to cater to a 35 per cent rise in the number of people on the planet.


Instead, a range of strategies was needed, including the development of more resource-efficient crops and increasing productivity on land that is not being used to its full potential.

"By identifying agricultural land that has not yet reached its full cropping potential we can direct yield intensification efforts - including crop genetic improvement and soil, nutrient and water management - to where they will be most productive," said University of Nebraska Professor Kenneth Cassman.

He said this could help avert a massive expansion of the land needed for crop production at the expense of carbon-rich and biodiverse rainforests, wetlands and savannah.

Dr Richard Richards of the Australian science agency CSIRO's plant industry division said scientists from a wide spectrum of disciplines would be needed.

"We need to combine advances in genetic technologies with opportunities for better crop management," he said.

"Genetic engineering has already made major contributions to pest and disease resistance and contributes to improved management practices but is unlikely to result in significant advances in yield or tolerance to stress," he said.

CSIRO researchers are also investigating the potentially damaging effects climate change will have on Australia's agricultural crops and native plants as carbon dioxide concentrations, temperatures and rainfall patterns change.

"We're facing an urgent need to develop new crop varieties for anticipated conditions in 20 to 50 years," said Dr Jairo Palta, a team leader with the agency's climate-ready cereals project .


Other researchers are studying potential strategies such as the controversial option of relocating plant and animal species under threat.

Moving species to areas that will be better suited to their survival - but where they have not yet lived - may become a key option as climate changes faster than they can adapt or disperse.

"While the virtues of managed relocation of species are being debated by the scientific community, the reality is that it is already occurring," said researchers from CSIRO, University of Queensland and United States Geological Survey in the journal Nature Climate Change.

"Without relocating species we are destined to lose some of our most important and iconic wildlife but at the end of the day we also need viable ecosystems into which we can move species," said CSIRO researcher Dr Tara Martin.

"Managed relocation is not a quick fix. It will be used in some specific circumstances for species that we really care about, but it will not be a saviour for all biodiversity in the face of climate change."

Melbourne University Professor Snow Barlow said winemakers needed to take climate change in their stride.

He said grape harvest dates in Australia were moving earlier by an average of 1-3 days a year.

"Either [winemakers] evolve the taste of their wines to something a little different because of the changing characters of their grapes, or they grow and employ another grape variety, or they change the region where they source their grapes," he said.