Global warning might aid N.Z.

Press, 6 December 1989, Page 15

Global warning might aid N.Z.

nzfa London New Zealand might enjoy increases in agricultural’ production as the greenhouse warming gains momentum. A preliminary report prepared for the Intergovernmental Panel on Climate Change outlines big shifts in world foQd production that can be expected within the next 50 years. The report, which summarises research by more " than 200 scientists world wide, says that crop yields are likely to increase significantly in the Soviet Union, China, Northern Europe, New Zealand and

Australia as atmospheric carbon dioxide concentrations double and temperatures rise accordingly. Vast areas of Siberia are likely to become viable for cropping as the climate warms, and in China the expected northwards extension of the monsoon would bring increased rainfall to regions where water shortages at present limit agricultural production. But in the United States, Canada and most European Community countries, rainfall and soil moisture will decrease, and crop yields will fall. This will markedly af-

fect the amount of food available for export on world markets and food prices, the report says. “In 1987, 77 per cent of all traded cereals came from only three countries: the United States, Canada and France.” All three are expected to experience significant production drops as the global warming gains momentum. The chairman of the working group which produced the report, Professor Martin Parry, of Birmingham University, said the greenhouse warming would make the present forms of agriculture less

viable in most parts of the world. “In fact, almost everywhere, apart from high latitudes and high elevations, will probably be drier,” he said. “Where levels of moisture are just sufficient for present forms of agriculture they may be insufficient in future, not because of any rainfall decrease, but because of higher evaporation rates where temperatures are warmer.” In the southern and central United States, Canada and southern Europe potential yields of crops are expected to

drop about 10 per cent by 2040, the report says. Exports of some United States crops could drop by up to 70 per cent. The report says in New Zealand there might be a decrease in wheat, barley and oat crops, but grassland production will increase. Maize, vegetable and kiwifruit yields will probably also increase, with the main growing areas shifting south. Berryfruit growing will move to the South Island and the wine industry will also move south. In Australia, although over-all yields are ex-

pected to rise, it is thought Western Australia will dry out, wiping out that region's large-scale wheat.industry;" Australia’s apple and pear industry is likely to decline and a shift from sheep to cattle will occur, the report says. While grass growth will increase as the climate warms, so will the problems of heat stress in sheep. Over-all, the report expects Australia’s wool production to increase as a result of a southward shift in sheep production and increases in the carrying capacity of rangeland.