A Growing Tinderbox: Wildfires Intensify Across the Canaries
Wildfires in the Canary Islands have become more voracious than they were just two decades ago. Over the last fifteen years, flames have scorched more than 55,100 hectares of Canarian woodland – an area equivalent to two islands the size of El Hierro – which corresponds to 7.4% of the entire Archipelago. Researchers in the Canaries warn that this trend is far from anecdotal and is increasing. The fires now find atmospheric conditions that favour them – higher temperatures, very low humidity, and a flattening of the thermal inversion layer – which are becoming more common across the Islands.
Abandoned Farms and Changing Climate Fuel the Flames
When these natural factors are combined with the abandonment of farmland closest to the laurel forest (laurisilva) zone, the Canaries become a tinderbox that fuels the emergence of major wildfires. These are the findings published in a recent article by a research group from the Chair of Natural Disaster Risks and Resilient Cities at the University of La Laguna (ULL). The group insists all these factors are sufficient to invite authorities to “rethink wildfire prevention measures.”
This is urgently emphasised by geographer Nerea Martín, lead author of the article, who notes that while “very good” systems have been developed for emergency action and response, prevention remains the major outstanding task. “It’s not simply about removing all the pine needles or felling the pine forest; measures must be taken from a joint, territorial perspective,” explains the geographer. Any action can have a reaction, and not necessarily a positive one. “These measures could lead to maladaptation, which is also possible,” she insists.
Gran Canaria’s Mosaic Landscape: A Model for Prevention
In this regard, Martín points to the work being carried out in Gran Canaria as an example of good practice. After suffering the effects of a major fire in 2019, the island has been preparing to avoid a similar event. “They are trying to create a mosaic landscape that acts as a firebreak,” she insists. Thus, within the same area, one can find stretches of cultivation coexisting with areas of natural vegetation, and grazing zones to keep ‘clean’ the areas where the urban network borders the woodland (the so-called wildland-urban interface).
High Mid-Altitude Zones: The Epicentre of Fire Risk
Precisely these interface zones are the most risky, as reaffirmed by the researchers in this work. “The high mid-altitude zones are the most prone to fire events,” explains Martín. The reasons are multiple. On one hand, the laurel forest has disappeared from this area because centuries ago it was decided to establish agricultural land there. The problem arises when these crops are abandoned – representing 20% in Tenerife and 40% in La Gomera – and the laurel forest begins to reclaim its space, which, in the earliest stages of this forest’s growth, means an increase in combustible biomass.
On the other side are the meteorological conditions, as the mid-altitudes are one of the zones where the effects of climate change are being felt most. “These are areas where those favourable meteorological conditions of low humidity, high temperatures, and the reduction or descent and flattening of the thermal inversion occur,” states the researcher. It is worth recalling that this same research group, in work led by ULL geographer Pedro Dorta, detected that this thermal inversion layer – which can appear in the Islands as a sea of clouds, ‘panza de burro’ (cloud layer), or mist – has descended 100 metres in the last half-century, driven by rising temperatures due to climate change.
This change in position is critical, as this moist, cool layer is precisely what, historically, protected the mid-altitudes from the devastating effects of fire. The final ingredient facilitating the advance of flames through this zone is where there exists, “to a greater or lesser extent,” a population that, whether through negligence or intentional causes, “can favour the ignition of fire.” According to the Canary Islands Government, the vast majority of fires in the Canaries are due to human causes, as natural causes are solely due to lightning strikes, a phenomenon not so common in the Archipelago.
Protected Natural Spaces and the Impact on Smaller Islands
Another area of concern are protected natural spaces. “Most fires occur there,” insists the geographer. In fact, approximately 81% of the areas burned in the last fifteen years were in protected natural spaces, demonstrating their high ecological vulnerability. “While it is true there is no affected population, from an ecosystem point of view, fires can cause erosion, landslides, or lead to flooding, which, ultimately, could indeed end up affecting inhabited areas,” she stresses.
To reach these conclusions, the researchers used satellite data. “By calculating the difference in light reflection before and after images taken from space, we can calculate the severity of each fire individually,” notes the researcher, indicating that thanks to this, they have been able to see “how it increases year after year.” Although the trend is clear, the researchers are cautious as they have limited data: “we have high-resolution satellite images since 2017, so earlier ones have low resolution and are not comparable.”
Despite the forcefulness of the data, one fact that has most caught the researchers’ attention is the effect fires have on the smaller islands. While the larger islands have the greatest burned area, relative to their size and population, they are far from being the most affected. “If you relativise and switch to percentage terms, La Palma becomes the island with the largest burned area,” highlights Martín. If, on the other hand, it is calculated in relation to emergency management, “from the point of view of impact on the population, we could say La Gomera is the most affected,” she notes.
In La Gomera, there has only been one fire in the last 15 years, the one in 2012, but it had a significant impact on the island, with 5,000 people evacuated. “Compared to the 26,000 evacuated in 2023 in Tenerife it might seem small, but for La Gomera it represents 22% of the population, almost the same proportion as it represented for Tenerife,” she indicates.
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