Tuesday, July 14, 2009

Expansion of the Tropics: evidence and implications

Source: James Cook University
"Growing scientific evidence shows the earth's tropical zone is expanding towards the north and south poles with the potential to radically change regional climates, researchers from James Cook Uni (JCU) in Townsville say. Dr Joanne Isaac and Prof Steve Turton said the trend had "immense" social, political, economic and environmental implications. They based their analysis on 70 previously published peer-reviewed research reports from scientists and institutions around the world using long-term satellite measurements, weather balloon data, climate models and studies of sea surface temperatures. The data suggested the pole-ward movement of the tropical zone could deliver drier conditions in some areas, eg southern Aust, southern Africa, the southern Europe-Mediterranean-Middle East region, south-western USA, northern Mexico and southern South America. At the same time, expansion north and south of the high-precipitation equatorial region could cause extreme rainfall events and floods in areas not previously exposed to such conditions. The researchers said the shift could also cause cyclonic activity over a wider range and increase the spread of tropical diseases and pests, eg malaria and dengue fever."