"They should have burned down preventive forest." "The fires have been lit." "What do you mean climate change, look at this graph." There are a lot of alternative statements about the forest fires in Australia. Sometimes the information is incorrect, but sometimes critics have a point. But you have to connect the right conclusions to that, experts explain to NU.nl.
We provide two experts with a number of alternative explanations about the fires. Cathelijne Stoof is a forest fire researcher at the University of Wageningen. Bart van den Hurk is a climate researcher at the Deltares knowledge institute and the VU University Amsterdam, and specializes in the relationship between climate and soil dehydration.
Misunderstanding 1: 183 people were arrested for arson
We can resolve this misunderstanding ourselves: the number is incorrect. This is announced by the Australian police. This figure also includes cases of people who were arrested before the current forest fire season started, and people who were arrested for completely different offenses.
Nevertheless, there is always a first flame in the event of a fire. What role does arson play in the current forest fire crisis in Australia? Cathelijne Stoof explains that other factors are more important.
"In the case of large wildfires, a guilty person is often searched in this way. But then you ignore the fact that for large forest fires three things are needed: a first flame, sufficient fuel and the 'right' weather conditions. Those weather conditions are drought and heat, as a result plants dry out and a lot of fuel becomes available. "
"The first flames are always there. But in a desert that doesn't cause a fire. And if the forest is wet enough, it doesn't spread far or can be checked."
Already in November the skies in Australia turned red because of the forest fires. Photo: Reuters
Misunderstanding 2: With firebreaks this had never happened
Stoof says that in addition, the so-called fuel-limiting measures are overestimated. Measures of this kind are, for example, the construction of firebreaks (strips without trees and shrubs) or the preventive burning of the undergrowth of pieces of forest.
"It is a misunderstanding that firebreaks or preventively burned undergrowth stop a violent forest fire." The sparks blow over it, and grasses can also transmit the fire. "Such measures are therefore intended to delay, so that the fire brigade in those places has a chance to stop the fire front."
"But what I hear from colleagues from Australia is that under these climatic conditions it has no effect whatsoever. The fire passes over firebreaks and areas of forest where undergrowth has been burned down preventively as well as through untreated area. This is due to the extreme drought: all plants are dried out, so the fire spreads everywhere at lightning speed. "
Misunderstanding 3: Simply use more firefighters
Stoof also says that it is sometimes surprising that people think that these fires can even be extinguished. When fire has reached a certain intensity, it simply becomes technically impossible.
"There are tables for that to illustrate. The water tank of a fire truck or fire extinguisher is then the proverbial drop on a glowing plate. You can slow down a little locally and protect strategic places, but not extinguish."
See also: What is the cause of the devastating forest fires in Australia?
Misunderstanding 4: Climate change leads to less rain
Does climate change play a role in the Australian forest fires or not?
The Australian government resolutely says no, but scientists tell a different story: these fires coincide with record heat and very extreme drought. This is partly explained by natural variation, and partly by global warming.
But does climate change strengthen the drought? Confusing graphs appear on social media. The picture below shows that the rainfall in Australia is not decreasing. And yes, that graph is correct.
Bart van den Hurk: "Precipitation trends in Australia are indeed small, and are strongly influenced by natural fluctuations in the temperature of neighboring oceans. For example, the graph shows a huge peak in 2010, when there was an enormous amount of rain due to the natural phenomenon of La Niña in the state of Queensland. "
It is true that climate change does not decrease the average rainfall. Yet climate change is increasing droughts through increased evaporation. (Source: Australian Bureau of Meteorology)
"But it is in any case a misunderstanding that climate change causes droughts solely through a decrease in rain. The risk of drought can also increase in areas with increasing rainfall, due to an increase in evaporation. If the rain fails to appear for a while, it suddenly becomes a strong factor. "
"Incidentally, there is one area in that region that receives structurally less rain due to climate change. That is the west coast of Australia and the adjacent part of the Indian Ocean. We see that pattern exactly this year again. In climatology it is called the ' positive phase "in the Indian Ocean dipole. We call that natural variation, but actually this climate fluctuation seems to be more likely to continue in the current direction. So along this route these droughts may also occur more frequently in Australia as a result of global warming. "
Misunderstanding 5: Australia is not getting warmer at all
Graphs are also circulating on social media that would indicate that Australia is not warming up. This often involves measurements within one season, for a short time series, or for only one measuring station.
"That is dangerous if you have a climate where you have such large fluctuations and where rainfall is also seasonal," says Van den Hurk. "And that also lends itself to manipulation. You can draw a graph between a peak and a valley, and then claim that the trend is going the other way."
Van den Hurk therefore refers to the long-term measurements of the Australian Bureau of Meteorology since 1910 of the average temperature for the whole of Australia. These measurements show that Australia has already warmed up 1.5 degrees and that the highest temperatures have fallen in recent years. This warming up is faster than world average.
"The December temperatures that we now see in Australia are even more extreme," says Van den Hurk. "They actually belong to a climate that is 3 degrees warmer: really extreme temperature deviations. And as a result, there is really no drop of water in the ground there anymore."
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Misunderstanding 6: Hooray, it's raining in Sydney. It is over
Unfortunately. Australia is big. And as we also learned in the Netherlands after the drought record in the summer of 2018: one shower does not stop the drought. Australia is still ahead most of the summer, and after a very long drought a lot of rain is needed for a long time, for soil moisture and groundwater to be restored.
"Another factor is that the vegetation has burned away," says Stoof. "He can no longer collect rainwater." And sometimes the soil is also damaged by the heat of the fires. If the soil does not absorb the moisture properly, the first rain can wash away again via the rivers, and the extreme moisture deficit in the soil is not simply replenished.
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