Syllabus: GS- III & V: Climate Change

Why in the News?

A new 20-year scientific assessment (2001–2021) has revealed alarming climate change–driven alterations in the Panidihing Bird Sanctuary in Sivasagar district, Assam. Using Landsat imagery through Google Earth Engine, researchers found sharp declines in rainfall, water spread, and flood intensity—signalling a larger wetland crisis across the state.

Key Concerns Highlighted by the Study 

1. Declining Rainfall and Rising Temperature

• Annual precipitation fell sharply from 1,343 mm (2001) to 1,055.8 mm (2021).
  
• Temperature and humidity showed a steady increase, resulting in higher evaporation rates.
  
• Reduced rainfall has weakened the hydrology of the wetland and its river systems.
  

2. Reduced Flood Intensity and Water Spread

• The Desang River’s high flood level at the Akhoiphutia gauge point showed a marked decline.
  
• The flooded area inside Panidihing shrank from 18.9 sq km (2001) to 5.9 sq km (2021).
  
• Seasonal flood spread reduced from 18 sq km to 4 sq km over the two decades.
  
• Post-monsoon water retention—critical for migratory birds—has dropped significantly.
  

3. Increasing Vegetation Encroachment

• As wetlands dried, vegetation increased from 18.6 sq km (2001) to 27.6 sq km (2021).
  
• During monsoons, vegetation coverage rose from 18.6 sq km to 23.5 sq km.
  
• Reduced inundation allows terrestrial vegetation to invade water bodies, shrinking habitat for birds.
  

4. Threats to Biodiversity and Nutrient Cycles

• Drying wetlands impact shorebirds, fish populations, and migratory species that depend on shallow floodplains.
  
• Reduced flooding disrupts carbon and nitrogen cycles, lowering soil fertility and altering food chains.
  
• Evapotranspiration-driven dryness increases the risk of habitat collapse.
  

Panidihing’s Ecological Importance and Current Status

• Spread across 33.9 sq km, Panidihing was designated as a sanctuary in 1996.
  
• Field surveys reveal only 15 wetlands remain, covering a mere 0.82 sq km.
  
• Its hydrology depends on the Brahmaputra, Desang, and Demow rivers.
  
• Siltation, weaker monsoons, and reduced river flow have compounded wetland shrinkage.
  
• The sanctuary, considered a potential Ramsar site, mirrors the condition of many wetlands across Assam.
  

Why Wetlands Matter: Explained Simply

• Wetlands act as natural sponges that absorb excess water and release it slowly.
  
• They support biodiversity, fisheries, migratory birds and groundwater recharge.
  
• Hydrological cycle refers to continuous water movement through evaporation, precipitation, infiltration and flow.
  
• Evapotranspiration is the combined loss of water from land and plant surfaces due to heat.
  
• Siltation occurs when sediments accumulate and choke water channels.
  
• Ramsar sites are wetlands of international importance designated under the Ramsar Convention.
  

A Statewide Pattern: Assam’s Wetlands Under Stress

Over the past 50 years, climate change and erratic monsoons have caused:

• A decline in wetland quantity and quality.
  
• Disrupted ecological services such as flood control and nutrient cycling.
  
• Reduced resilience against climate extremes.
  

What Needs to Be Done: Policy and Conservation Pathway

Wetland restoration and hydrological repair must include:

• Strengthening water connectivity between rivers and wetlands.
  
• Removing siltation through scientific dredging.
  
• Establishing community-led monitoring systems.
  
• Integrating wetlands into climate adaptation plans under the National Action Plan on Climate Change.
  
• Leveraging the National Wetlands Conservation Programme for long-term protection.
  
• Identifying and designating critical sites as Ramsar wetlands for global support and governance.
  

Conclusion

Panidihing is a microcosm of Assam’s broader ecological challenge. As climate change intensifies, wetlands—nature’s climate shock absorbers—are shrinking. The future of Assam’s biodiversity, hydrology and local livelihoods depends on urgent, coordinated hydrological restoration and strong conservation governance.

Exam Hook

Key Takeaway: Climate change has drastically weakened flood cycles and water retention in Assam’s wetlands, demanding urgent hydrological restoration and climate-resilient wetland policies.
Possible Mains Question: “Shrinking wetlands in Assam reflect a climate-induced hydrological crisis. Discuss its ecological impacts and the key interventions required for long-term wetland resilience.”

https://epaper.assamtribune.com/full-page-pdf/epaper/pdf/2025/12/11/the-assam-tribune/7284