Article 1: Climate Variability and Rising Flood Risks in India
Why in News: The India Meteorological Department has forecast below-normal monsoon rainfall (92% of LPA), but increasing extreme rainfall events continue to pose significant flood risks across India.
Key Details
- IMD has predicted below-average rainfall; however, this does not reflect regional and intra-seasonal variability. This means even with lower overall rainfall, certain regions may still experience intense rainfall episodes.
- Extreme rainfall events have increased significantly in frequency and intensity over recent years. These events are often localised and can trigger floods, landslides, and urban waterlogging.
- India has experienced at least one major flood or rainfall-related disaster every year since 2013. This indicates a structural shift in monsoon behaviour rather than isolated anomalies.
- Climate change is a major driver behind the increasing unpredictability and intensity of rainfall patterns. It amplifies hydrological extremes by altering atmospheric moisture and circulation patterns.
Indian Monsoon System
- Monsoon Dynamics: The Indian monsoon is driven by differential heating of land and sea, along with seasonal wind reversal. This process leads to large-scale moisture transport from oceans to the Indian subcontinent.
- Spatial and Temporal Variability: Rainfall distribution varies across regions and time, making all-India averages less indicative. For example, surplus rainfall in one region may offset deficits in another at the national level.
- Intra-seasonal Variations: Active and break cycles lead to uneven rainfall distribution within the season. These variations often result in concentrated rainfall within short durations, increasing flood risk.
- Forecast Limitations: Seasonal forecasts cannot accurately predict localised extreme rainfall events. They are better suited for broad trends rather than precise location-specific predictions.
Extreme Rainfall Events and Trends
- Definition (IMD): Rainfall above 21 cm in 24 hours is classified as extremely heavy rainfall. This classification helps in issuing warnings and disaster preparedness measures.
- Rising Frequency: Such events have increased from around 60–70 annually to over 150 in recent years. This sharp rise indicates a clear trend beyond natural variability.
- Intensity Concerns: Rainfall is occurring in shorter, more intense bursts. This increases runoff and reduces infiltration, thereby raising flood risks.
- Threshold Changes: Revision in classification thresholds partly explains the rise in numbers. However, even after adjusting for this, the increasing trend remains evident.
Climate Change and Hydrological Impacts
- Global Warming Link: A warmer atmosphere can hold more moisture, leading to intense precipitation. This increases the likelihood of heavy rainfall events over short durations.
- Erratic Patterns: Climate change is making rainfall more unpredictable and unevenly distributed. This creates simultaneous risks of floods in some areas and droughts in others.
- Increased Extremes: Both floods and droughts are becoming more frequent and severe. This dual impact complicates water resource management and planning.
- Scientific Consensus: Studies consistently link extreme rainfall trends to anthropogenic climate change. This makes climate adaptation a critical policy priority for India.
Major Flood Disasters in India
- 2013 Kedarnath Disaster: Triggered by cloudbursts and glacial activity, causing massive destruction. It highlighted the vulnerability of Himalayan ecosystems to extreme weather events.
- 2018 Kerala Floods: Resulted from unprecedented rainfall and reservoir mismanagement. It was one of the worst floods in nearly a century in the region.
- 2015 Chennai Floods: Caused by intense rainfall combined with poor drainage systems. It exposed serious gaps in urban planning and disaster preparedness.
- Recurring Pattern: India has witnessed at least one major rainfall disaster annually since 2013. This indicates increasing vulnerability rather than isolated extreme events.
Urban Flooding and Governance Issues
- Unplanned Urbanisation: Encroachment on wetlands and floodplains reduces natural drainage capacity. This leads to severe waterlogging even during moderate rainfall events.
- Infrastructure Gaps: Urban drainage systems are often outdated and inadequate. They are unable to handle sudden surges of water during extreme rainfall.
- Municipal Challenges: Poor waste management blocks drainage channels. This further worsens flooding conditions in cities.
- Economic Impact: Flooding disrupts transport, business, and daily life. It causes significant economic losses and affects urban productivity.
Challenges in Weather Prediction
- Chaotic Nature: Weather systems are highly sensitive to initial conditions. Small changes can lead to vastly different outcomes over time.
- Prediction Limits: IMD can forecast heavy rainfall but not exact intensity precisely. This limits the accuracy of disaster preparedness measures.
- Uncertainty Factor: More localised forecasts tend to have higher uncertainty. This makes precise prediction of extreme events difficult.
- Technological Needs: Improved models and data systems can enhance prediction accuracy. However, complete elimination of uncertainty is not possible.
Disaster Management Framework in India
- Institutional Setup: Agencies like NDMA and IMD coordinate disaster preparedness and response. They play a key role in issuing warnings and managing emergencies.
- Policy Measures: Flood management programmes and early warning systems are in place. However, their effectiveness varies across regions.
- Financial Impact: Floods account for over 50% of disaster-related expenditure by states. This highlights their economic burden on public finances.
- Casualties: Thousands of people have lost their lives due to floods in recent years. This underscores the need for better preparedness and mitigation strategies.
Shifting Policy Focus: From Drought to Flood Risk
- Earlier Concern: Rainfall deficiency and drought were primary concerns. These affected agriculture and rural livelihoods significantly.
- Current Challenge: Excessive and localised rainfall has become a bigger threat. It leads to sudden disasters with immediate impacts.
- Urban Vulnerability: Cities are more exposed due to dense populations. Infrastructure stress amplifies disaster impacts.
- Need for Adaptation: Policies must focus on resilience and preparedness. This includes both structural and non-structural measures.
Way Forward
- Climate-Resilient Infrastructure: Develop better drainage and flood management systems. This will reduce vulnerability to extreme rainfall events.
- Improved Forecasting: Invest in advanced weather models and technologies. Better forecasts can enhance early warning systems.
- Urban Governance Reforms: Enforce land-use regulations strictly. This will prevent encroachment and reduce flood risks.
- Integrated Approach: Combine climate adaptation with disaster management. A holistic strategy is essential for long-term resilience.
Conclusion
Below-normal rainfall does not eliminate flood risks, as extreme events are increasing due to climate change. India must shift focus from total rainfall to its intensity and distribution, ensuring better preparedness and resilience.
EXPECTED QUESTION FOR UPSC CSE
Prelims MCQ
Q. With reference to extreme rainfall events in India, consider the following statements:
- Below-normal monsoon rainfall ensures a lower probability of floods.
- Extreme rainfall events are increasing in both frequency and intensity in India.
- Climate change has no significant role in influencing rainfall variability.
How many of the above statements are incorrect?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (b)