Australia–– BUSHFIRE risk has increased sharply since the 1970s, with an index that measures the severity of fire weather conditions near Melbourne having risen nearly 50 per cent in four decades.
A study of weather conditions before bushfires at 38 sites across Australia shows the state capital’s score on the Forest Fire Danger Index rose by 49 per cent between 1973 and 2010.
None of the sites, including metropolitan Melbourne and Sydney, were safer from severe fire conditions than they were a generation ago.
The Forest Fire Danger Index, or FFDI, is a points system measuring bushfire risk, from low to catastrophic. Advertisement
“Fire weather, as depicted by the FFDI, has increased across much of Australia since 1973,” said the report, produced by researchers at the Climate Change Research Centre at the University of NSW and published in the Inter-national Journal of Cli-matology.
“The largest absolute changes occur in the hot, arid interior of the continent, although some of the largest proportional increases occurred in coastal areas, where average annual cumulative FFDI is relatively low Melbourne and Adelaide recorded increases of 49 per cent or more over the duration of the record.”
The rating system involves tallying the data on rainfall, evaporation, heat, wind speed and humidity to arrive at a number that signifies the degree of fire risk on any given day.
Conditions such as those preceding the Black Saturday fires, in which 173 people died, are still extremely rare.
“The Black Saturday forest fires of February 2009 . . . were driven by some of the highest FFDI values on record, against a background of severe drought conditions in the preceding months and years,” the report said. The trend across practically the whole country was for longer fire seasons, and more fires in spring, though not necessarily more fires in summer.
The report also summarised other recent research, and found that inland, south-eastern Australia was seeing the biggest increases in fire danger.