Pune: India’s forests may store far more carbon in the coming decades, but scientists have warned the trend comes with a catch — the country’s most important forest ecosystems could become more vulnerable.A new study by the Indian Institute of Tropical Meteorology (IITM), BITS Pilani, Goa, and Lund University, Sweden among others, projected that carbon stored in living forest vegetation — trunks, branches, leaves and roots — could rise by 35% under low greenhouse gas emissions, 62% under medium emissions and 97% under high emissions by 2100.At first glance, that appears positive. Forests act as carbon sinks, absorbing carbon dioxide from the atmosphere. But researchers said the finding was not entirely good news.“It is a good thing that carbon stock is increasing, but overall it is not a positive signal… Today’s forests are becoming more vulnerable for the future, and the capacity of that forest is decreasing,” said lead author from IITM, Fitha Fathima.The study used climate “what-if” scenarios based on IPCC (Intergovernmental Panel on Climate Change) emission pathways — low, medium and high — to simulate forest response from 1960 to 2100 using a dynamic global vegetation model.Across all scenarios, forest carbon increases nationally — from a historical average of 7.74 kg per sqm to 10.24kg per sqm (low), 11.76 kg per sqm (medium) and 13.67 kg per sqm (high emissions) by the end of the century. But the gains are uneven.The largest increases are projected in desert and semi-arid regions, including Rajasthan, Gujarat and parts of central India. Western Ghats and Eastern Himalayan forests — among India’s most carbon-rich ecosystems — show modest increases.“These regions are currently among the densest forests. If they are showing modest increases, it indicates vulnerability,” Fitha Fathima explained, adding that this signalled a shift in forest health rather than simple growth.IITM scientist Dr Roxy Mathew Kollsaid, “India’s forests are not responding to climate change in a uniform way. Some regions may store more carbon in living biomass, but that does not mean climate change is helping forests. A warmer world is also bringing greater risks from drought, fire and other disturbances. What this study shows most clearly is that rainfall matters deeply, and that future forest planning must be regional, climate-aware and rooted in risk prevention.“The study, recently published in “Environmental Research: Climate”,found that rainfall was the dominant driver of forest carbon changes at the national scale, with effects appearing after a lag of two years. Temperature played a stronger role within regions, especially under higher emissions.Researchers cautioned that the projections captured only a part of the picture. “This is one of the first forest dynamics modelling efforts from India, utilising a second generation Dynamic Global Vegetation Model (DGVM). This needs to be followed up with further modelling experiments where plot based vegetation dynamics, including nutrient limitations, could be simulated,” said Rajiv Chaturvedi, scientist, BITS Pilani, Goa campus.“Deserts and semi-arid regions show the largest increase in forest carbon biomass, consistent across the emission scenarios. The growth in the Himalayan and Western Ghats remains lower. Overall, precipitation remains the major driver; its influence wanes with emissions, and warming takes over, which must be taken into consideration for nature-based mitigation management,” said IITM scientist Pramit Deb Burman.Scientists flagged that real-world risks, including wildfires, droughts, heatwaves and land-use change, were not fully captured in the model, but could significantly affect how long forests retain this carbon.
