Den stora tråden om global uppvärmning/växthuseffekten

Police in Australia are on the hunt for arsonists behind 12 bushfires deliberately lit during this week's catastrophic conditions across New South Wales.

Police allege a 16-year-old boy started a central Queensland bushfire that has destroyed a staggering 14 homes … the deliberately lit Cobraball fire, near Yeppoon, is still burning days after it destroyed homes, sheds and cars.

A suspected arsonist has been arrested after an extraordinary chase through the bush in the Royal National Park, south of Sydney, by an Army Black Hawk helicopter.

Two youths have been arrested after allegedly setting a fire during a Total Fire Ban in Kingscliff earlier this week ... the boys allegedly gathered paper, dry leaves and vegetation and ignited it using a cigarette lighter.

Authorities suspect two fires that started on Tuesday in Turramurra on Sydney's north shore and Loftus in the Royal National Park were deliberately lit.

A 20-year-old man has been charged after allegedly lighting a bushfire in a Balgownie reserve … in the space of just five minutes, the fire destroyed about 150sq m of bushland.

Police are seeking public help to crack down on suspicious behaviour around several Lake Macquarie fires that began on Tuesday.

[Queensland’s] new bushfire arson unit, Taskforce Overcross, has investigated dozens of deliberately lit blazes in the past two months with 74 people charged.

Three teenagers have been arrested after a fire was deliberately lit in Harrington Park overnight.

The fire was ignited in bushland off The Northern Rd and was spotted by a passing motorist about 5.30pm.

Firefighters from Fire and Rescue NSW and the RFS had the blaze extinguished about 45 minutes later.

Camden police, tipped off by members of the public, searched the nearby area and arrested a 15-year-old boy and 16-year-old boy near Harrington Parkway.

A third boy, aged 15, was arrested shortly after.

Large wildfires can only occur when there is a combination, at the same time, of three things:

• an ignition source,
• severe fire weather and,
• a large contiguous accumulation of fuel.
• Remove any of these three and you cannot have a large wildfire (= megafire).

We obviously can’t control the weather, nor can we hope to eliminate all possible avenues of ignition. The only factor we can control is the large contiguous accumulations of fuel. Therefore, broadscale fuel reduction burning is the only defence we have against large wildfires. This will not prevent fires occurring, but it will ensure fires are less intense, are easier and safer to control and will do less damage.

Does it work? Yes it does, as has been shown many times, over many years, by the experience of Western Australian forest managers. The “proof of the pudding” is the incidence of large wildfires in Western Australian forests over the last 50 years. There were a number of very large fires in Western Australian forests from 1900 to 1960, but after the 1961 Dwellingup fire disaster, the wide-scale fuel reduction program carried out by the then Forests Department, ensured that the fuel accumulation was well controlled. The graph below demonstrates this very clearly. It was only after the burning program gradually fell away following a diversion of resources away from forest areas, that the area of wildfires began to climb again after about 1990.