Human-altered mountains drive most fatal landslides worldwide, analysis finds

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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 paper is published in the journal Science Advances.

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.

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 destabilizing hill slopes. 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, categorized 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 cover of their countries. Such changes could include deforestation, and expansion of farmland and infrastructure.

Land-use-land-cover change correlates with fatal landslides

The current study states, "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, "Economically disadvantaged countries often also face 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.

Publication details

Seçkin Fidan, Wealth and land cover change govern landslide fatalities on world's mountains, Science Advances (2026). DOI: 10.1126/sciadv.aec2739. www.science.org/doi/10.1126/sciadv.aec2739

Journal information: Science Advances

Key concepts

landslideland use and land coverdeforestationpopulation (human)

Provided by University of Vienna