Climate change affecting safe winter chill for orchard trees. A new study says that global warming will impact fruit and nut tree productivity in Australia and globally. Most fruit and nut trees have evolved in cool temperate climates and go through a dormant winter phase and require a certain amount of winter chill to trigger their spring growth and fruit production. But with strong trends in many regions for warming winter minimum temperatures and reduced number of 'winter chill' days, the heat is on our orchards.
Temperatures are projected to rise in most parts of the world with winter minimum temperatures projected to rise most rapidly. Our orchards have been established taking account of current climate conditions, which are now rapidly changing due to greenhouse gas pollution contributing to climate change. This will have a major impact on costs and productivity of fruit and nut orchards, an industry estimated to be worth about US$93 billion globally in 2005.