India’s forests, long considered natural carbon sinks, are losing their ability to absorb carbon dioxide, with photosynthetic efficiency falling by up to 12% in dense forest zones over the past two decades, according to a new study from IIT-Kharagpur. This decline threatens to undermine India’s climate strategy, which relies heavily on afforestation and forest expansion to meet emission reduction goals.
The study, led by professor Jayanarayan Kuttippurath at IIT-KGP’s Centre for Ocean, River, Atmosphere, and Land Sciences, found that despite increasing “greenness” in forest areas, actual carbon uptake is weakening. The research reveals that forests in the Western Ghats, Eastern Ghats, and western Himalayas areas known for dense tree cover have seen some of the steepest drops in photosynthetic activity, mainly due to soil dryness and rising heat stress.
Using satellite data and computational modeling, the researchers assessed vegetation health, leaf area index, and soil moisture trends from 2000 to 2019. Their analysis shows an average 5% decline in photosynthetic efficiency, which is critical for converting atmospheric carbon into plant biomass.
These findings challenge recent forest reports. The Union Environment Ministry’s 2024 forest assessment claimed a gain of 1,445 sq km in forest area between 2021 and 2023 and noted progress toward India’s 2030 carbon sink target of 2.5 to 3 billion tonnes. But IIT’s study questions whether these forest gains are translating into actual climate gains.
Kuttippurath’s team warns that only 16% of India’s forests currently exhibit “high integrity”, meaning most ecosystems are not functioning at optimal ecological health. Factors such as deforestation, increased agricultural encroachment, commercial plantations, and extreme weather events could turn many forests into savanna-like landscapes, reducing biodiversity and resilience.
Supporting this concern, an earlier IIT Bombay study in 2023 led by Subimal Ghosh found that even as India’s forest “greenness” grew by 6%, the plant productivity decreased by the same percentage highlighting that more trees do not necessarily equal more carbon capture.
The authors urge urgent interventions: protecting native forests, improving water use efficiency, rethinking plantation policies, and incorporating science-based planning for tree planting initiatives. They also call for aggressive emission cuts and responsible forest resource management to meet the 2070 net-zero target.
“Our forests can’t just be green on paper—they need to be functional and healthy,” said research scholar Rahul Kashyap. “This study shows that quantity without ecological quality won’t help us fight the climate crisis.”