Block’s Indicator of Sustainable Growth

by Ray Block

Researchers at James Cook University in Townsville, which is situated north of the tropic of Capricorn say that “climate change is rapidly expanding the size of the world’s tropical zone, threatening to bring disease and drought to heavily populated areas.”

The findings showed the tropics now extended well beyond the traditional definition of the equatorial band circling the Earth between the tropics of Cancer and Capricorn.

The researchers led by Professor Steve Turton have been looking at long term satellite measurements, weather balloon data, climate models and sea temperature studies to determine how global warming was impacting on the tropical zone.

These now sub-tropical areas include regions of southern Australia, southern Africa, the southern Europe-Mediterranean-Middle East region, the south western United States, Northern Mexico, and southern South America.

All of these areas are predicted to experience severe drying. “If the dry subtropics expand into these regions, the consequences could be devastating for water resources, natural ecosystems and agriculture, with potentially cascading environmental social and health implications.”

Professor Turton, who is executive director CSIRO/JCU Tropical Landscapes Joint Venture said that tropical diseases such as dengue fever were likely to become more prevalent.

James Cook vice chancellor, Sandra Harding said the evidence showed climate change was already affecting wildlife and rainfall in Australia. She said studies showed changes to wind patterns meant rain was now being dumped in the ocean south of the continent, rather than over land.

There is also evidence that many Australian animal and plant species are moving south in an attempt to track their preferred climatic conditions. “Some won’t make it. Tropical climate conditions are expanding and the impact of this expansion is immense, because the tropics are a big, complex and important zone of the world,” Professor Harding said.