Scientists comment on wildfires in Scotland.
Dr Catherine Smith, research associate in the Leverhulme Centre for Wildfires, Environment and Society, Royal Holloway, University of London, said:
“Large wildfires like these are becoming more common in Scotland, and we can expect to face more wildfires like this in the future. Climate change is one factor – greater extremes of weather in the spring and early summer are making it more likely that vegetation becomes dry enough to fuel wildfires. Another important factor is how landscapes are managed. In many parts of Scotland the amount of grazing, especially with cattle, and the controlled use of fire in the winter and early spring (known as muirburn) have decreased in recent decades. This means that there is lots of old and drier vegetation on many moorlands, which, again, is fuel for larger wildfires.”
Joe McNorton, Scientist, Earth System Modelling Section, European Centre for Medium-Range Weather Forecasts, said:
How unusual or expected are these wildfires?
“AI driven (Probability of Fire) Fire forecast models predicted a medium fire danger for parts of the highlands at the end of June, this is rare given the models are typically used as forecasts in more fire prone-regions such as the African Savanna or Mediterranean. Typically, even in peak summer months, we would not expect these global models to pass the threshold for even medium fire danger in the highlands. So whilst the fires are unusual a risk was identified prior to the fires.
Do we know why they have happened now and in these locations?
“By looking at the inputs that inform the data driven fire danger models, we can evaluate what drove such events. In this case the prolonged hot dry weather resulted in both the live and dead vegetation drying out creating a tinderbox effect. This coupled with the availability of fuel in the form of vegetation meant that only an ignition source was required to create the wildfires observed. Wind conditions and a continuity of fuel to burn aided in the spread of the fire across the landscape.”
Prof Rory Hadden, Chair of Fire Science, University of Edinburgh, said:
“It is widely expected that the number of wildfires will increase in Scotland (and the UK) as we see more periods of extreme weather driven by climate change. The recent fine weather means that vegetation has dried out and becomes susceptible to ignition sources. Even a small heat source such as a BBQ or campfire can initiate a wildfire either by direct flame contact with vegetation, or by igniting a smouldering fire in dry vegetation and soils which will later transition to a flaming fire.
“Once vegetation is ignited, a fire will grow extremely rapidly especially if there is wind and/or dense vegetation. This is especially true given the recent weather conditions in Scotland and means that typically it will be challenging to fight without proper resources. Also a smouldering fire in soils may only transition to flaming some hours after it is ignited (and there may be no obvious signs that smouldering has been ignited). Once ignited a fire will spread rapidly through vegetation, moving fastest in the direction of the wind and up slopes. Poor access, difficult terrain and extensive vegetation coverage means that the fire can spread over large areas relatively quickly.
“The impacts of these fires are of course significant. There is a huge cost to the fire and rescue services in fighting and managing these fires – drawing resources from a wide area. There is the destruction of natural capital – the countryside provides important ecosystem services that we all rely on and these are impacted negatively by wildfires. Loss of vegetation impacts on wildlife. The smoke is harmful and can impact on people large distances away, exacerbating respiratory conditions. If the fire burns into peat soils then the loss of carbon to the atmosphere will be significant and may drive future climate change. There is also possibility of loss of property as fires move towards settlements (farms, villages, towns).
“While there is ongoing research on this topic, there is lots we do not know around the changes in risk to people, property and environment posed by wildfires in Scotland and the UK. The fire and rescue services are adapting but there is currently no national fire danger assessment tool or clear coordination at Government level in Scotland. We need to work on finding measures to manage fire risk in Scotland and the UK, including fuel load management (e.g. prescribed burning, mechanical means) as well as communications with stakeholders and the public to advise of periods of higher fire danger. This is critical because as well as climate change, we are in a period of significant changes in land use (including rewilding) across Scotland and the UK.
“It is important to note that the leading cause of wildfires is people. We all need to do our part when visiting the countryside to ensure we do not bring ignition sources – pack a picnic instead of a BBQ, and only have campfires in designated areas.”
Declared interests
Dr Catherine Smith: “No interests to declare.”
Joe McNorton: “I can confirm I have no interests that may give rise to a potential conflict.”
Prof Rory Hadden: “Funding declaration:
US Department of Agriculture, Forest Service;
US Department of Commerce, National Institute of Standards and Technology;
Funding on unrelated projects from Defence and Security Accelerator;
UKRI EPSRC.”