Farmers may benefit from rising temperatures

By Shelly Simonds

Australian farmers could benefit from global warming as rising temperatures impact on world commodity prices, an economist visiting the ANU said.

La Trobe University Professor of Agricultural and Resource Economics Tony Chisholm told an ANU forum on global climate change that shifts in commodity prices will have a greater impact on Australian farmers than changes in climate.

Prof Chisholm presented a survey of meteorological and economic models to a conference sponsored by the Academy of Social Sciences and the Academy of Science, among others.

They showed the potential impact of climate change on agriculture in Australia and around the world.

"It's very important to think globally on this issue, not just about Australia," said Prof Chisholm.

Most scientists agree greenhouse gases including carbon dioxide and methane in the atmosphere will double or triple over the next 50 years. These gases are likely to cause temperature increases and agriculture will suffer if people don't adjust land use to the new climate.

Prof Chisholm said if yields for crops such as wheat, sugar and rice fell around the world, prices would rise and because Australian agriculture is heavily export oriented, farmers would get a better return for their crops.

In the worst-case scenario, based on 1994 data from the United Kingdom Meteorological Office (UKMO), world crop yields could drop by 12 per cent, nearly doubling market prices. However, in a less dramatic forecast using the same data, accounting for the ability of farmers to adapt methods and seed varieties to gradual temperature shifts, prices rise by 25 per cent.

Prof Chisholm said it was difficult to predict how climate change would affect agriculture because the data used as a basis for economic models varied widely. UKMO models predicted greater change than those presented by the Goddard Institute of Space Studies (GISS) in the United States. GISS data predicted only a 0.1 per cent drop in yields leading to an 8 per cent rise in market prices. Where humans adapt well to new conditions, world yields actually rise and prices drop 8 per cent.

Scientists are stepping up efforts to study how climate change could increase pests and disease in agricultural areas and how changes in rain patterns will effect agriculture in the future.

"Much of Australia's rangeland is dependent on the monsoonal rains," said Prof Chisholm. "Rather than what happens to mean temperature, what happens to rain patterns could matter more to farmers."