Despite the common perception of landslides to be naturally controlled, a new study reveals that most fatal landslides occur in human-transformed environments. Conducted by an international team of researchers from the University of Vienna, Ankara University, Istanbul Technical University, Bursa Uludag University, and the GFZ Helmholtz Centre for Geosciences, the study provides a global overview of how human pressure modulates landslide occurrences. The most important finding of the study is that land-use-land-cover change has a substantially greater influence on landslide fatalities than physical factors such as topography and precipitation, especially in low- and lower-middle-income nations. The study is published in the prestigious journal Science Advances.
Landslides are among the most destructive hazards, typically killing over 4,500 people and causing $20 billion in damage annually. The starting point for this research was a critical global question: why are landslides deadlier in certain regions than others with comparable terrain and climate? As populations exposed to hazards in mountain areas have doubled since 1975, it's important to understand that human alterations to the land surface—such as clear-cutting, agricultural transition, and road construction—are drastically destabilising hillslopes. This study highlights how increasing human made pressure on nature exacerbates the vulnerability of socioeconomically disadvantaged people.
Quantifying human made changes in the context of landslides
The researchers focused on mountainous landmasses across 46 countries, categorised by national income levels. They addressed a massive dataset comprising approximately 60 years of land-use-land-cover changes and 45 years of population dynamics. The team introduced a new metric, the total land-use-land-cover change, to quantify overall human alterations, integrating this with topography, precipitation, and exposure models.
The findings are striking: while high-income nations altered only 7% of their mountainscapes, low-income countries changed 50% of the mountain land covers of their countries. Such changes can be deforestation, and expansion of farmlands and infrastructure.
Land-use-land-cover change correlates with fatal landslides
The current study finds: "In countries like Haiti, Sri Lanka, and El Salvador, this land-use-land-cover change correlates with a surge in fatal landslides and death tolls. However, this correlation weakens in wealthy nations such as Switzerland, Japan, and Italy, which experience fewer fatalities despite landslide prone topography and climates", explains one of the authors Ugur Öztürk from the University of Vienna. The lead author, Seckin Fidan from Ankara University, adds that "Economically disadvantaged countries often face also substantial population pressures unlike wealthier nations. These pressures lead to the rapid clearing of fragile mountainous areas for farming, informal housing, and basic infrastructure needs."
Land-use-land-cover change emerges as a critical driver of mortality, alongside national wealth. Countries that manage to maintain low land-cover change experience fewer landslide fatalities despite being highly prone to the hazard. The authors of the study thus clearly demonstrate that minimal human intervention in land use in mountainous regions reduces the risk of fatal landslides.
Summary:
- The researchers wanted to determine why fatal landslides are distributed unevenly across nations with similar physical hazard potentials.
- They found that land-use-land-cover change influences landslide fatalities substantially more than natural topography or precipitation, particularly in lower-income countries.
- Anthropogenic changes in mountainscapes (e.g., deforestation, infrastructure expansion) act as a disaster multiplier, amplifying the vulnerability of the world's poor.
- Effective and sustainable land-use planning is a critical, life-saving necessity for disaster risk reduction in low and lower-middle-income countries.
About the University of Vienna:
At the University of Vienna, curiosity has been the core principle of academic life for more than 650 years. For over 650 years the University of Vienna has stood for education, research and innovation. Today, it is ranked among the top 100 and thus the top four per cent of all universities worldwide and is globally connected. With degree programmes covering over 180 disciplines, and more than 10,000 employees we are one of the largest academic institutions in Europe. Here, people from a broad spectrum of disciplines come together to carry out research at the highest level and develop solutions for current and future challenges. Its students and graduates develop reflected and sustainable solutions to complex challenges using innovative spirit and curiosity.
