Context

Recent studies reveal that India’s forests are facing a silent crisis driven by rising temperatures, erratic rainfall, and deforestation, highlighting the ability of forests to absorb carbon dioxide (CO2) & in the photosynthesis process and carbon uptake.

• ISRO is undertaking several long-term studies under its Geosphere-Biosphere Programme to understand the impact of climate change on 12 different forest types in the country. 

Key Findings of the Study On Carbon Absorption

• Impact of Rising temperature on Photosynthesis: 
  • Rising  temperatures hinders enzyme growth which is crucial for photosynthesis, despite initial CO2-induced boosts. 

• • Water stress from hotter temperatures and changing rainfall patterns further disrupts this vital function.
• Decrease in Carbon Absorption: In key forested regions of Northeast, Peninsular India and the Western Ghats, despite an increase in green cover, there has been a decrease in CO2 absorption over the past two decades (2001-2019).
• Effects Examined on Leaf Area Index (LAI,a measure of the total green cover of a region) & net primary productivity (NPP, the total CO2 absorbed by plants after accounting for respiration).
• • Based on Variation of Species and Canopy: Variations in species types and canopy structures impact photosynthetic efficiency. 
    • Canopies with multiple layers are better at photosynthesis than single-canopy forests because of the increase in photosynthetic space.
  • Based on Types of Forest :The photosynthetic ability of tropical forest trees generally starts to fail when the leaf temperature reaches 46.7 degree celsius. 
    • It says that An average atmospheric temperature rise of  4°C temperature increase may halt primary nutrition production in tropical trees
• Delay in the process of leaf senescence: During the winter of 2019-20, a delay in the process of leaf senescence as compared to the winter of 2018-19.
• Phenological Changes on Fauna: 
  • Climate-induced phenological shifts affect not only plants but also birds and animals. Mismatches in phenological events can disrupt ecosystems, leading to cascading effects.  For example: 
    • Over the past five decades, the arrival times of 117 European migratory bird species in spring have been getting out of sync with other spring events like when leaves appear and when insects start flying. This mismatch can affect bird survival.
• Need for Elaborative Studies: Though it is a Ground-level study which highlights the adverse effects of global warming on forests. Long-term observational studies are needed to understand the combined impact of climate variables on forests & to formulate effective mitigation strategies. 

Conclusion

India’s forests face multifaceted challenges exacerbated by climate change. Understanding the intricate interactions between warming temperatures, CO2 levels, and forest ecosystems is essential for effective mitigation strategies.