[Paper Review] Impact of Climate Change on Forests in India

NH Ravindranath, NV Joshi+2 more|ArXiv.org|Nov 2, 2005

Plant Water Relations and Carbon Dynamics16 references134 citations

TL;DR

This study assesses the impact of climate change on Indian forests using climate projections from the HadRM3 model under A2 and B2 emissions scenarios, coupled with the BIOME4 vegetation model. By 2085, 77% (A2) and 68% (B2) of forested grids are projected to shift forest types, with wetter types in the northeast and drier types in the northwest, alongside increased net primary productivity—doubling under A2 and rising 70% under B2—highlighting the need for climate-informed forest planning despite uncertainties in projections.

ABSTRACT

Global assessments have shown that future climate change is likely to significantly impact forest ecosystems. The present study makes an assessment of the impact of projected climate change on forest ecosystems in India. This assessment is based on climate projections of Regional Climate Model of the Hadley Centre (HadRM3) using the A2 (740 ppm CO2) and B2 (575 ppm CO2) scenarios of Special Report on Emissions Scenarios and the BIOME4 vegetation response model. The main conclusion is that under the climate projection for the year 2085, 77% and 68% of the forested grids in India are likely to experience shift in forest types under A2 and B2 scenario, respectively. Indications are a shift towards wetter forest types in the northeastern region and drier forest types in the northwestern region in the absence of human influence. Increasing atmospheric CO2 concentration and climate warming could also result in a doubling of net primary productivity under the A2 scenario and nearly 70% increase under the B2 scenario. The trends of impacts could be considered as robust but the magnitudes should be viewed with caution, due to the uncertainty in climate projections. Given the projected trends of likely impacts of climate change on forest ecosystems, it is important to incorporate climate change consideration in forest sector long-term planning process.

Motivation & Objective

• To evaluate the projected impact of climate change on forest ecosystems across India by the year 2085.
• To assess shifts in forest types under different greenhouse gas emission scenarios (A2 and B2).
• To quantify changes in net primary productivity (NPP) due to elevated CO2 and warming.
• To inform long-term forest management by integrating climate change projections into planning processes.
• To highlight uncertainties in climate model projections while identifying robust trends in forest ecosystem responses.

Proposed method

• Climate projections were generated using the Hadley Centre's Regional Climate Model (HadRM3) for India.
• Two emissions scenarios—A2 (740 ppm CO2) and B2 (575 ppm CO2)—were used to project future climate conditions.
• The BIOME4 vegetation model was applied to simulate shifts in forest types based on projected climate variables such as temperature and precipitation.
• Spatial analysis was conducted across grid cells representing forested regions in India to assess changes in forest type distribution.
• Net primary productivity (NPP) was modeled under elevated CO2 and temperature to estimate changes in carbon sequestration potential.
• Model outputs were evaluated for robustness, with caution advised on magnitude due to uncertainty in climate projections.

Experimental results

Research questions

• RQ1 How will climate change projected for 2085 affect the distribution of forest types across India?
• RQ2 What are the projected changes in net primary productivity (NPP) under the A2 and B2 emissions scenarios?
• RQ3 In which regions of India are forest types most likely to shift toward wetter or drier conditions?
• RQ4 How do elevated CO2 concentrations and warming influence forest ecosystem productivity and composition?
• RQ5 To what extent can the projected impacts be considered robust despite uncertainties in climate modeling?

Key findings

• By 2085, 77% of India’s forested grids are projected to experience a shift in forest type under the A2 emissions scenario.
• Under the B2 scenario, 68% of forested grids are expected to undergo a shift in forest type by 2085.
• In the absence of human influence, forest types in the northeastern region are projected to shift toward wetter types, while those in the northwestern region are expected to shift toward drier types.
• Net primary productivity (NPP) is projected to double under the A2 scenario due to increased CO2 and warming.
• NPP is estimated to increase by nearly 70% under the B2 scenario, indicating significant productivity gains in response to climate change.
• Despite robust trends in forest type shifts and productivity increases, the magnitudes of change should be interpreted with caution due to uncertainties in climate model projections.