Northern and central portions are at the greatest risk, says research paper

Before the turn of the century no less than 56 per cent of India's forests will be transformed under global warming, and among the most vulnerable will be the Western Ghats, says a new study published in the latest edition of Current Science.

The northern and central portions of the Western Ghats, primarily the most deciduous and evergreen forests of Karnataka, are at the greatest risk, says the research paper authored by scientists at the Indian Institute of Science (IISc). While open forests of the northern Western Ghats “may drive up vulnerability”, the central part of the Western Ghats will experience temperature rise (projected at 3 degrees) that is disproportionately higher than the precipitation increase.

Much of these forests are also fragmented, putting them at greater risk of forest fires and pest attacks, it adds. However, the southern part of the Western Ghats, dominated by tropical wet evergreen forests appears to be quite resilient to the climate change. The changes in ecology could occur over decades, N.H. Ramanathan, an author of the paper, told The Hindu.

“The changes could occur through forest die-back that undermines the physiological functions of the forest such as pollination and regeneration,” he said.

For the study, the scientists created a digital map of India that they divided into over 1,65,000 grids. Of these, 35,899 grids were classified as “forest grids”, and the analysis was based on climate projections, atmospheric CO2 concentration and a dynamic vegetation model. It found that 30.3 per cent of the “forested grids” across the country are likely to undergo change by 2035, and 56.2 per cent by 2085. The largest concentration of “vulnerable forested grids” were found to be in the northern part of the Western Ghats, the Eastern Ghats, the upper Himalayan stretches and parts of Central India.

Climate change is only going to add to the multiple stresses that forests witness today, including over-extraction, pest outbreaks, livestock grazing and forest fires, caution the authors Ranjith Gopalakrishnan, Mathangi Jayaraman, Govindasamy Bala and Ravindranath representing Centre for Sustainable Technologies, Centre for Atmospheric and Oceanic Sciences and Divecha Centre for Climate Change at IISc.

The high-altitude mountainous forests of the Himalayas are also highly susceptible to the adverse effects of climate change.

In contrast, the forests of northeast India are least vulnerable because the climate “is predicted to get hotter and wetter there, which is conducive to the existing vegetation types.” India must monitor the vegetation response to changing climate in the long term, the paper recommends.