THE WEATHER EXPERIENCED BY SUGARCANE PRODUCTION SYSTEMS IN NORTHERN QUEENSLAND HAS CHANGED OVER THE PAST 80 YEARS

THERE IS INCREASING evidence that the environmental potential for Australian cropping production systems has changed measurably over the past hundred years. Analysis of rainfall records in the Western Australia wheat belt has shown a significant decrease in in-season rainfall over that period. Across the whole of the Australian wheat belt both an increase in temperature and a decrease in rainfall have been known to lead to a decrease in the environmentally determined yield potential and a possible contributor to stalled wheat yield per area in Australia. In a recent investigation of CCS trends in the northern sugar growing region around Mulgrave Mill, the weather records of the region were analysed. Rainfall and maximum and minimum temperatures from the Cairns region date back to the late 1800s and early 1940s respectively. The monthly rainfall, maximum and minimum temperatures were analysed using linear regression and comparison with the 1961?1990 average (anomaly analysis commonly used in climate research). The results show that for many months of the year there has been an increase in the average maximum and minimum temperatures of over 1 ?C in the past 70 years. For rainfall the effect was less clear and most marked in the harvesting season in October. The results are discussed in relation to the growth and development processes of sugarcane and other operations in the sugar production system. These results demonstrate that climate change is not only a future consideration but there has already been measurable change. Further analysis across the whole industry would be a useful next step to determine more broadly the changing environment sugarcane production systems are operating under.