Model Answer
0 min readIntroduction
The Indian monsoon, a defining feature of the Indian climate, delivers approximately 75% of the country’s annual rainfall, profoundly influencing agriculture, economy, and livelihoods. Traditionally, the monsoon’s behaviour was governed by large-scale atmospheric and oceanic phenomena like the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). However, in recent decades, there’s growing evidence suggesting that human alterations to the landscape are increasingly influencing monsoon patterns, leading to increased variability, intensity, and spatial distribution changes. This raises concerns about the future predictability and reliability of this vital climatic system.
Understanding the Traditional Indian Monsoon
The Indian monsoon is not a single entity but a complex system driven by differential heating of land and sea. The summer monsoon, crucial for kharif crops, is triggered by the northward movement of the Intertropical Convergence Zone (ITCZ) and the development of a low-pressure system over the Tibetan Plateau. The winter monsoon, though weaker, brings rainfall to the southern peninsula. Historically, these patterns were relatively stable, with predictable onset and retreat dates.
Humanizing Landscapes and Their Impact
Deforestation and Land Use Change
Large-scale deforestation, particularly in the Western Ghats and Northeast India, reduces evapotranspiration, diminishing atmospheric moisture and potentially weakening monsoon circulation. Conversion of forests to agricultural land alters surface roughness and albedo, impacting local weather patterns. According to the Forest Survey of India (2021), India lost approximately 0.5% of its forest cover between 2019 and 2021.
Urbanization and the Urban Heat Island Effect
Rapid urbanization leads to the creation of ‘urban heat islands’ (UHIs), where cities experience significantly higher temperatures than surrounding rural areas. This temperature difference can disrupt local wind patterns and influence convective rainfall, leading to increased instances of extreme rainfall events in and around urban centers. Studies by the Indian Institute of Technology (IIT) Delhi have shown a correlation between UHI intensity and localized flooding in major Indian cities.
Agricultural Practices
Intensive agriculture, particularly paddy cultivation, increases evapotranspiration, contributing to atmospheric moisture. However, unsustainable agricultural practices like excessive groundwater extraction and fertilizer use can degrade land and reduce its capacity to absorb rainfall, exacerbating flood risks. The Green Revolution, while boosting food production, also led to increased water consumption and land degradation.
Infrastructure Development
Large-scale infrastructure projects like dams, canals, and highways alter natural drainage patterns and can disrupt the monsoon’s flow. Dams, while providing water storage, can also reduce downstream flow and impact local rainfall patterns. Road construction and urbanization increase impermeable surfaces, leading to increased runoff and urban flooding.
Evidence of Changing Monsoon Behaviour
- Increased Frequency of Extreme Rainfall Events: India has witnessed a significant increase in the frequency of heavy rainfall days (above 150mm) in recent decades, leading to devastating floods.
- Shifting Rainfall Patterns: The spatial distribution of rainfall is changing, with some regions experiencing increased rainfall while others face prolonged droughts.
- Delayed Monsoon Onset and Retreat: The onset and retreat of the monsoon are becoming increasingly erratic, impacting agricultural planning.
- Weakening of the Monsoon Circulation: Some studies suggest a weakening of the overall monsoon circulation, potentially linked to changes in land use and atmospheric aerosols.
| Factor | Impact on Monsoon |
|---|---|
| Deforestation | Reduced evapotranspiration, weakened circulation |
| Urbanization | Urban Heat Island effect, localized heavy rainfall |
| Agricultural Practices | Increased evapotranspiration, land degradation, altered runoff |
| Infrastructure Development | Disrupted drainage patterns, altered rainfall distribution |
Conclusion
The evidence strongly suggests that humanizing landscapes are indeed influencing the behaviour of the Indian monsoon, contributing to increased variability and extreme weather events. While natural climate variability remains a dominant factor, the impact of anthropogenic changes cannot be ignored. A holistic approach that integrates sustainable land management practices, climate-resilient infrastructure development, and effective water resource management is crucial to mitigate the adverse effects and ensure the long-term sustainability of the Indian monsoon and the livelihoods it supports. Further research and improved climate modeling are also essential to better understand these complex interactions.
Answer Length
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