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Why Are Landslides Becoming More Frequent? The Role of Anthropogenic Activities, Climate Change, and Unsustainable Human Behaviour

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Introduction

  • As we have discussed in the last blog, through the facts, landslides have become one of the most important environmental and disaster-management issues of our time. 
       

  • This is not merely because they are natural geomorphic processes, but because their frequency, intensity, and socio-economic impacts appear to be increasing, making them a regular feature in global news headlines. From the Himalayas and the Andes to Southeast Asia and East Africa, reports of devastating landslides causing widespread destruction have become increasingly common.
  • In simple terms, a landslide is the downslope movement of rock, soil, or debris from a higher elevation to a lower elevation, following the slope gradient, under the influence of gravity. 
  • In our previous blog-
  1. We explored the science behind landslides, 
  2. their mechanism, 
  3. slope stability, and 
  4. the major types of landslides. Therefore, we will not revisit those concepts here.
  • Instead, this article focuses on a far more important question: Why are landslides becoming an issue of such global concern if they are fundamentally natural processes?
  • The answer lies in the rapidly changing relationship between humans and the natural environment. While landslides have occurred throughout Earth's geological history, human activities have significantly increased both the likelihood of their occurrence and the scale of their consequences. 
  1. Extensive -&- Inplanned urbanisation,
  2. Indiscriminate deforestation, 
  3. Large-scale road construction, 
  4. Hill topography drilling -&- cutting, 
  5. Mining, 
  6. Hydropower infrastructure development and 
  7. Auxiliary infrastructure expansion have disturbed the natural stability of slopes. 
  8. But, most importantly, particularly in the context of recent temporal dimensions,  the warming planet and climate change have intensified extreme rainfall events, further increasing slope instability.
  • As a result, what was once primarily a natural geomorphic process has increasingly transformed into a major natural hazard, causing widespread environmental degradation, loss of life, destruction of infrastructure, and severe economic disruption. In many cases today, it is not the landslide itself that is entirely "natural," but rather the human-induced modifications of the landscape that amplify both its probability and its destructive impact.
  • Therefore, this blog is not about understanding what a landslide is; rather, it seeks to explain why landslides are becoming more frequent, more destructive, and more relevant in the twenty-first century, with a special emphasis on the role of anthropogenic activities, changing climate, and unsustainable development practices.
 


Slope Stability: The Interplay Between Driving and Resisting Forces

     


  • As we discussed in the previous blog and shown in the above infographics, landslides are the result of the interplay between two opposing forces—the driving force and the resisting force. The driving force is primarily the downslope component of gravity, while the resisting force is provided by the shear strength of the rock and soil mass.
  • A slope remains stable as long as the resisting force exceeds or equals the driving force. However, once the resisting force becomes less than the driving force, the equilibrium is disturbed, the slope loses stability, and a landslide occurs. Thus, the stability of a slope is essentially an outcome of the balance between these two forces. This we can easily understand by the comparison between the Himalayas -&- Western Ghats through "a comparative infographic"; in conclusion of that we shall know why western ghats is less susceptible to landslides in comapison of Himalayas.

  • It is important to understand that the primary factor determining whether a landslide will occur is not merely the steepness of the slope, but the shear strength of the rock or soil, which is higher in the Western Ghats that why less susceptible to landslides. Steep slopes can remain stable for thousands of years if the underlying materials possess sufficient shear strength. Conversely, even moderately inclined slopes may fail if their shear strength is significantly reduced.
  • The reason is simple. Gravity continuously exerts a downslope force on every slope. However, when the rock and soil have adequate shear strength, they can resist this "gravitational stress", thereby maintaining slope stability. The following infographics illustrate this principle. 
          

  • Trees can grow vertically and remain firmly anchored on steep mountain slopes despite the constant pull of gravity. Likewise, stable rock faces can withstand gravitational forces for centuries without collapsing. These examples demonstrate that high shear strength effectively resists the downslope stress generated by gravity, allowing the slope to remain in equilibrium.
  • This brings us to the central question of this blog. If gravity has always existed, why are landslides becoming more frequent and more destructive today?
  • The answer lies largely in anthropogenic activities. 

  • Human interventions such as Uncivilised manner, deforestation, hill cutting, road construction, mining, quarrying, unplanned urbanisation, hydropower development, and other forms of slope modification gradually reduce the shear strength of the lithosphere. As the resisting force weakens while gravitational stress remains unchanged, the balance shifts in favour of the driving force. Consequently, slopes become increasingly unstable, resulting in more frequent and catastrophic landslides.
  • Therefore, to understand the growing landslide crisis, we must examine the hierarchy of anthropogenic factors that are progressively weakening slope stability across the world.



The hierarchy of anthropogenic factors: Four (04) most prominent factors


1. Unplanned Urbanisation: The Primary Anthropogenic Driver of Modern Landslides

  • Among the various anthropogenic factors responsible for the increasing frequency and severity of landslides, unplanned urbanisation and infrastructure development occupy the foremost position.
  • It is important to distinguish between traditional rural settlements and modern urban expansion. Rural settlements generally evolve in closer harmony with the surrounding landscape and involve relatively limited modification of the natural terrain. In contrast, urbanisation often begins with large-scale alteration of the physical environment to accommodate expanding populations and economic activities.
  • As urban settlements grow, they require-
  1. extensive civic infrastructure, 
  2. including roads, 
  3. tunnels, 
  4. drainage networks, 
  5. sewage systems, 
  6. water supply pipelines, 
  7. electricity transmission lines, 
  8. communication facilities, and 
  9. public buildings. 
  • In mountainous regions, these developments frequently involve-
  1. hill cutting, 
  2. excavation, 
  3. blasting, 
  4. quarrying, and 
  5. large-scale earthworks. 
  • Such activities disturb the natural equilibrium of slopes by removing supporting material, creating artificial cut slopes, and generating fractures within the rock mass. Consequently, the shear strength of the slope gradually declines, reducing its ability to resist the downslope pull of gravity.
  • The problem becomes even more severe when urban development is poorly planned. Inadequate drainage systems allow rainwater to infiltrate the ground, increasing pore-water pressure and saturating the soil. This further weakens the resisting force and significantly increases the likelihood of slope failure.
  • Road widening, border-road construction, hydropower projects, tunnels, dams, mining, and other engineering works often require continuous excavation of unstable hill slopes, which further accelerates this process. While these projects are essential for economic development and national security, the importance lies in ensuring that we can drop or even slow down these projects, particularly in international border states. So, the only solution lies in adequate geological assessment of slope stabilisation measures, which can substantially decrease landslide susceptibility.

2. Water Logging and Weathering

  • These anthropogenic disturbances become particularly hazardous during-
  1. the monsoon season,
  2. Illegal civil construction; the "Kedarnath tragedy" in year of 2013 in Uttarakhand was due to this reason, just because an unwanted illegal artificial lake emerged during the time because of illegal civic interference, and 
  3. large hydropower infrastructure development project riding on poor construction planning/faults.
  • As discussed in the previous blog, landslides are a type of mass wasting, while weathering is one of the major exogenic processes that gradually weaken rocks. So all three major factors- heavy amounts of water infiltrating the slope accelerate chemical, physical, and biological weathering, which progressively reduce the shear strength of rocks and soils. At the same time, saturation increases pore-water pressure, decreasing friction between particles. Once the resisting force falls below the gravitational driving force, the slope collapses, producing a landslide.
  • This explains why landslides occur most frequently in mountainous regions, all through the Himalayan and Western Ghats belt, during periods of intense or prolonged rainfall.

3. Global Warming: The Emerging Multiplier of Landslide Risk

  • Today, climate change and global warming have emerged as powerful risk multipliers rather than direct causes of landslides. Rising global temperatures have- 
  1. intensified the hydrological cycle, 
  2. increased the frequency of extreme rainfall events in many mountain regions. As a consequence, 
  3. more intense precipitation results in greater slope saturation, 
  4. faster weathering, 
  5. stronger erosion, and 
  6. more frequent mass wasting events.
  • Deforestation associated with rapid urbanisation further compounds the problem. The removal of vegetation-
  1. Reduces root reinforcement, 
  2. exposes soil directly to rainfall, and 
  3. decreases slope stability. Simultaneously, deforestation 
  4. releases carbon dioxide (CO₂) into the atmosphere, 
  5. contributes to global warming and further intensifies extreme weather events.
     
The devastating landslides in Dharali village,
 Uttarlashi district of Uttarakhand.

  • The devastating landslides in Dharali village of Uttarlashi district of Uttarakhand in the year of 2025 and several other Himalayan states demonstrate this interaction clearly. Scientific investigations have consistently shown that these disasters were caused by combinations of factors, but the effects of global warming and climate change are among the most important, further corroborated by increasing "cloud bursts" in mountainous regions, particularly in the Himalayas. Together, these factors weakened slope stability and transformed heavy rainfall into catastrophic landslides.
  • Therefore, the modern landslide crisis is no longer merely a geological phenomenon. It is increasingly the outcome of unsustainable development interacting with a changing climate, making landslides more frequent, more destructive, and more challenging to manage than ever before.


4. Unsustainable Human Behaviour: The Invisible Driver of Landslide Risk

  • Among the major anthropogenic factors contributing to landslides—unplanned urbanisation, global warming, weathering and waterlogging, and unsustainable human behaviour—the most fundamental and often invisible driver is unsustainable human behaviour. This is because every human intervention that destabilises slopes, whether deforestation, hill cutting, mining, quarrying, reckless construction, or improper land use, ultimately originates from human decisions and behaviour.
  • If individuals, communities, industries, and governments collectively adopt a sustainability-oriented mindset, many destructive activities can be prevented or carried out with appropriate environmental safeguards, significantly reducing landslide risk. Conversely, if human behaviour continues to prioritise short-term economic gains over long-term ecological stability, even the most comprehensive government policies, engineering measures, and disaster-management strategies will have limited success. Therefore, unsustainable human behaviour is the underlying driver that amplifies environmental degradation and weakens slope stability, making it one of the most critical long-term challenges in reducing landslide hazards and achieving sustainable development.


We May Conclude

  • Landslides are not becoming more destructive because gravity has changed, but because human activities are increasingly disturbing the natural equilibrium of mountain slopes. Throughout this article, we have seen that while gravity provides the driving force, it is the "progressive weakening" of the resisting force—through unplanned urbanisation, weathering and waterlogging, global warming, and, above all, unsustainable human behaviour—that transforms a natural geomorphic process into a devastating natural hazard. Having identified the principal causes of the problem, we are now better prepared to discuss its broader geographical dimensions. Just as an effective cure requires an accurate diagnosis, effective landslide mitigation requires a clear understanding of the factors responsible for slope instability. 
  • In this blog, we explored both the natural and anthropogenic factors responsible for the increasing frequency and intensity of landslides, with particular emphasis on anthropogenic influences.
  • In the next blog, we will examine the global spatial distribution of landslides, identify the regions most vulnerable to slope failures, and analyse why certain parts of the world—and India in particular—experience a disproportionately high landslide risk.

Thanks.
Critical comments are welcome


 













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