Australian Bushfires

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Sometimes there's a reason, we can't attribute all calamities to climate change. Hopefully this helps with the understanding.

Submitted: December 19, 2019

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Submitted: December 19, 2019

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Fire is a tool of nature but it can be devastating, terrifying and cruel which is why we must show empathy for Aussies whenever they face it.

As many people have, newspaper columnist Gwynne Dyer in today’s paper has attributed climate change as being the cause of the Aussie bushfires. He added some emotion to it by saying that CO² in the atmosphere is now 405ppm, which looks a big number when written like that. But as a fraction it’s 405 over 1 000 000 equating to .0405% of the atmosphere. ‘We are nearing tipping point!’ he says. To put it into something understandable, there are 86400 seconds in 24 hours, .0405% of a day equals just under 35 seconds. Up from 0.04% and increase of 0.43 of a second. I get his drift but claiming the fires are caused by an overabundance of CO² seems odd, when fire extinguishers a full of the stuff!

Eucalyptus trees have a volatility of their own caused by the oil in their foliage. While they’re an evergreen species, they shed leaves throughout the year. To some extent they self prune, branches die and fall to the ground. Many Eucalyptus species (and there are some 600) shed bark, which will burn readily, and many others have loose, dry, hanging bark on their trunk. All of this litter gradually builds up, hardly breaking down into the environment. In most forest situations litter holds moisture, but Australia is climatically very hot and dry so there’s no moisture in the duff layer. Lying on the ground’s surface is a volatile fuel source just waiting to burn. This is perfectly natural, has been occurring for thousands of years and has nothing to do with CO² or climate change. The temperature doesn’t need to be 40?C for it to burn fiercely, it soon builds up its own heat, causes its own draught and with enough heat, even the green foliage burns readily.

When I was a young forestry trainee, we were told that given enough heat, Eucalyptus forest can spontaneously ignite – while temperatures in the city may reach 40?C, in forest gulleys, the temperature can be considerably hotter. The theory has now been discounted, apparently there’s no such thing… and yet? So what could start the fires? The only natural way is lightning. Which leaves man - igniting fires accidentally or on purpose. Small things such as bottles acting like a magnifying glass, or branches touching power lines. Once the fire reaches the crown, twigs and smouldering leaves can be lifted by the heat of the fire and carried off on the wind, so the hotter the air temperature, the longer and further smouldering embers stay alive as they fly. Smouldering embers falling into volatile litter, are fanned by the wind to start new fires. Fire creates its own draught, and when secondary fires occur, they draw towards each other, fire attracting fire and the closer they become, the faster they draw – it’s deathly to be between them!

That’s why Aussie firefighters have it so tough, and why they have my admiration and empathy.  But it’s nothing to do with higher levels of CO² or climate change.


© Copyright 2020 moa rider. All rights reserved.

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