20 January 2020
Willy Tinner is a specialist when it comes to the history of European fires. In this interview, the paleoecologist and OCCR member talks about the link between the bushfires in Australia and climate change, how the symbolic power of fire helps the climate movement and why Mediterranean countries shouldn’t plant any more pine trees.
Willy Tinner, how unusual are the current bushfires in Australia?
Even in the Mediterranean region, fires destroy astonishingly large areas of forest every year. In Italy the average area is over 1,000 square kilometres per year, in Spain it’s as much as 2,000 square kilometres. If you extrapolate that to the area of Australia, you get about 30,000 square kilometres, which is half the size of Ireland. In Europe – meaning the Mediterranean – we are familiar with fires that correspond size-wise to the current disaster in Australia.
But large parts of Australia are deserts, where there are hardly any fires...
... and that’s the problem: the fires are concentrated in New South Wales. This concentration makes these fires truly extraordinary. If you look at the affected regions only, the areas that have been devastated are 20 times larger than what we know from the Mediterranean region. This is really crazy. Even in Alaska, where large fires are common, you get numbers like here in Europe. But that means that every year, forests the size of canton Bern burn down. Seen in this light, the fires of the past few weeks in Australia are really frightening and so far unique. But it won’t necessarily stay that way; fires on an Australian scale are also threatening Europe.
What about the fires in the Amazon?
I deliberately didn’t mention them – they’re of completely different dimensions; it's about ecosystems which are not adapted to fire, thus the ecological damage is much biger. Above all, however, these fires are deliberately started by people. I was only talking about unintentional or natural fires. It must be said, however, that most of these fires are also human-induced – in the Mediterranean region, the figure is over 90%. It’s not arson, but plain carelessness. Cigarettes or such unbelievable causes as sparks from the railway. In Ticino, for example, an above-average number of fires start along the railway lines.
And when can carelessness develop into large-scale forest fires?
The weather is decisive: if it’s always raining and cold, you can barbecue outside without any danger. In fire weather, however, this becomes a problem. This means very dry and hot conditions. In this respect, the conditions in Australia and also in the Mediterranean area have deteriorated extremely.
Is this a consequence of climate change?
Yes, that is undisputed. We are dealing with longer and more extreme periods of heat, which are also associated with drought. If strong winds are added to this combination, it will be very bad. Worst of all is when the fire itself ignites these winds. This is when the so-called fire tornadoes arise, which are also notorious in the Mediterranean region. A fire that covers a square kilometre can generate its own wind system. This creates a tremendous thermal. And then we find ourselves in a negative spiral of dry and hot weather, with fire and firestorms that transport burning particles for kilometres.
In your research projects you are investigating past forest fires in Europe. Are the present fires also exceptional from a historical perspective?
Among hunter-gatherers, fires were an insignificant phenomenon, but as soon as people started to build up a production economy, this changed. In the lake sediments, where we detect charcoal particles, it is quite clear that the fires increased the moment that people became interested in producing something. One may wonder why this is so. Man had had fire much earlier – since about half a million years, already Homo erectus was familiar with fire – so it wasn’t an achievement of modern man. The increase in fires that we see has to do with the fact that the early farmers built their production systems in the forest...
...you’re referring to slash-and-burn.
Exactly. We see that all over Europe. People are trying to use fire to create favourable conditions for crops that come from the Middle East and need plenty of light and dry conditions. To do this, they have to make clearings. This approach is repeated again and again, because nature has a tendency to close the wounds created by slash-and-burn agriculture. If you want to interrupt this process, you have to clear it with fire again. With the advent of the production economy, there was more and more fire in the system. This started in the Neolithic Age, increased in the Bronze Age, when people settled down, and finally culminated during the Iron Age. There are real fire industries in some places in Europe. In the Lüneburg Heath and in many other areas of Western Europe, the valuable heather was preserved by burning it down a little every year. This is where man has installed proper fire vegetation after clearing.
What role do climate developments play in this fire history of Europe?
At the Oeschger Centre, we try to link the climatic changes with those in the history of vegetation. There was a phase in the Early Holocene around 8,000-10,000 years ago when the Mediterranean region was relatively dry and hot. This had nothing to do with the greenhouse effect as it does today, but rather with the orbital parameters that led to very strong solar radiation in summer. Our investigations of Sicily and Sardinia during this period show that it burned even more than today under the influence of humans. This is worrying. We know from our studies that species that had adapted to fire were more common at that time. Perfidiously, some of these species burn very well themselves because they contain a lot of essential oils...
...like the eucalyptus that’s burning in Australia.
Exactly, in addition to the fire weather, the so-called firewood plays a big role in Australia. Eucalyptus has so many essential oils that it burns almost explosively. This leads to the fire tornadoes I was talking about. In the Mediterranean region it is species such as cistus, sage or rosemary that burn so quickly – all plants that we appreciate so much because they smell good.
Greta Thunberg started her protests in 2018 against the backdrop of the forest fires in Sweden. She says that without this environmental disaster on her own doorstep, there would never have been a movement. People in Australia are also demonstrating against their government. In terms of climate policy, are people particularly sensitive to fire?
Yes, I think so. There is something symbolic about fire. It stands not only for security and warmth, but also for danger. A fire practically on your own doorstep is a powerful image – just like the polar bears on ice floes. But in contrast to this, people are directly threatened by fire. This raises awareness of climate change. This can be seen very clearly in Australia, where criticism is now coming from people who had hardly taken to the streets for the climate until now.
Are there strategies for adapting to the increasing risk of forest fires?
Yes, through plants that suppress fire. Olives, holm and cork oaks, for example. These plants form shadows, and their shedding of foliage is linked to processes that tame fire to a certain extent. In our reconstructions, we see that fire frequency decreases when there’s an evergreen olive-oak forest. We therefore recommend that cities and forestry services in the Mediterranean region plant trees that are less fire-prone than eucalyptus and pine. With our vegetation models we can show that it would be much better to use plants that occur naturally in the forest. They form a moisture shield and could possibly act as fire-breakers. This method should be tested right away.