Research improves Europe's protection against landslides
In the decades ahead, landslide risk will probably increase in some regions of Europe as a consequence of climate change and growing population. But landslides’ danger can be hidden: though their destruction is plain, in official data landslides are often lumped in with their triggers, such as extreme precipitation, earthquakes or floods. This means that damage wrought by landslides is generally underestimated by analysts, and public awareness of landslide risk is less than that of comparable natural hazards.
Landslides especially affect Europe because of the continent’s landscape and dense population. According to the Centre for Research on the Epidemiology of Disasters, over the last century Europeans have experienced the second-highest number of fatalities and the highest economic losses caused by landslides of any continent. Though the number of fatalities caused by landslides is not as high as other natural hazards, the number of people impacted can be sizeable. An estimate in Italy found that for each death, another 50 people were impacted by damage to home or property.
In order to examine landslide risk and predict changes over the next century across the continent, the European Commission funded €6.6 million towards a recent research project called SafeLand. The first task of the research team, comprising 27 partner institutions in 12 countries, was to improve the scientific understanding of how landslides occur. Though common natural landslide triggers are known – such as extreme rainfall or snowmelt – they can also be caused by human actions such as clearing land and road construction. Scientists are still trying to develop an understanding of the mathematical relationship between triggers and landslide risk. The process involves comparing theoretical predictions with observed landslide, and no-slide, events in recent years.
The researchers then applied these improved mathematical models to determine which areas of Europe are currently landslide “hotspots”, judged both by their likelihood of landslides as well as the risk of damage. They found hotspots clustered in predictable places, such as the mountain ranges of Italy and Norway, but also in less expected countries including Montenegro, Macedonia and Romania. Approximately 40 percent of the population of small alpine countries such as Lichtenstein and Montenegro are exposed to landslides.
Finally, the research team studied how landslide risk in selected areas would change over the next 100 years. SafeLand applied models of climate change to landslide-prone regions in Scotland, southern Italy, the French Alps, and southern Norway. They found that at a local level each of these areas saw an increased likelihood of landslides, even when the results at the national scale indicated no significant change. They concluded that local modelling is essential to accurately predict the changing pattern of landslide risk.
Importantly, human actions are as significant as climate changes in shaping future landslide risk. “There are two dimensions of risk,” explains Bjørn Kalsnes, head of the SafeLand project. “Our impression is that changes in demography are perhaps more important than changes in climate, at least over the timescale we’re looking at.”
That gives landslide-prone areas the option of managing development by for instance, discouraging people from settling near slopes, or prohibiting forest clearing in order to manage landslide risk. SafeLand also screened 14 existing early-warning systems and reported on their applicability for different landslide types, scales and risk management steps. They created checklists that any regional authority can now use in choosing a landslide early-warning system.
Finally, the project demonstrated a new method for consulting the public on matters of natural hazards. In Nocera Inferiore, Italy, SafeLand researchers held meetings with residents, conducted surveys, and distributed information via lectures and websites. The goal of this work was to accurately communicate landslide risk and allow public participation to shape Nocera Inferiore’s mitigation and prevention strategy, which is still under development.
“You may have the best technical solution in the world but if it’s not possible because of political reasons, or resistance of the local population, then it doesn’t help anybody,” says Farrokh Nadim, scientific coordinator of SafeLand. “We looked at this from a scientific point of view in our case studies, and I think we made really groundbreaking progress, showing the way this can be done in the future”, Nadim adds.