The study — published by NCBS researchers Dina N Rasquinha and Mahesh Sankaran in the 'Current Science' journal — predicts the consequence on biomes of the country under two different emission scenarios. (A biome is a distinct ecological community of plants and animals that co-exist in a particular climate.)

They concluded that under these two scenarios — called RCP (Representative Concentration Pathways) 8.5 and RCP 4.5 — India's total protected area will potentially experience biome shifts by the latter part of the century by 18 per cent and 14 per cent (486,243 sq km), respectively. This implies that several ecological areas including forests are vulnerable and will be in danger if climate change mitigation measures are not adopted.

Experts say that the continued heavy exploitation of certain biomes (such as the forest, freshwater, and marine) would have severe implications. "We sought to understand the potential shifts in the distribution of biomes in India by 2070 under different emission scenarios, identify biomes and regions of the country that are particularly at risk from future changes in climate," say the authors. RCPs are four greenhouse gas concentration trajectories; while emissions will continue to rise throughout the 21st century in RCP 8.5, emissions in RCP 4.5 will peak around 2040, and then decline.

"Drier and currently more arid tropical regions appear particularly at risk, with most of the drier tropical biomes likely to be replaced by wetter biomes in the future. Temperate biomes are predicted to be dominated by vegetation characteristic of a warmer climate in the future.

These results are consistent with climate predictions from global and regional models, which suggest increases in precipitation and temperature over large parts of the country in the future," conclude the authors.

Why this matters

A biome is identified mainly by the type of vegetation that grows there, which is determined by the local climate. The type of vegetation, in turn, determines the type of animals that can be found there. So, a shift in the climate increases the risk the risk of biodiversity extinction and other ecological changes.

Experts say that it is critical to preserve all types of biomes because each house unique forms of life. For instance, forests are important as they are not only home to various biotic communities, but they also have a global climate-buffering capacity. Their destruction may cause massive changes in global climate. Explaining the importance of conserving aquatic biomes, researchers from the University of California Museum ofPalaeontology said that "their medium, water, is a major natural resource, which supports life, and countless species live in it for all or part of their lives. Freshwater biomes supply us with our drinking water, and water for crop irrigation. The world's oceans have an even greater effect on lobal climate than forests do. Water has a high capacity for heat, and because the earth is mostly covered with water, the temperature of the atmosphere is kept fairly constant and able to support life".

Vulnerable areas

The researchers say that their results suggest that biome shifts will be largely concentrated in the east-central and northern and western parts of the country, and the tropical and subtropical dry forests, savannas, grasslands and xeric habitats were particularly at risk. "By 2070, tropical and subtropical moist broad-leaf forests are likely to completely replace tropical and subtropical grasslands, and also occupy about 51 per cent of the area currently covered by tropical and subtropical coniferous forests, about 24 per cent of the area of temperate broadleaf and mixed forests, about 18 per cent of the area of tropical and subtropical dry broadleaf forests," the paper says.

"Tropical and subtropical dry broadleaf forests will occupy about 23 per cent of the area currently covered by deserts and xeric shrub-lands, and 5 per cent of the area of tropical and subtropical moist broadleaf forests. Further, about 16 per cent of the area of deserts and xeric shrub-lands will be occupied by savannas and grasslands.

Temperate regions, on the other hand, will likely be dominated by a warmer climate. Montane grasslands and shrub-lands will potentially occupy about 6 per cent of the area currently covered by ice, 8 per cent of the area of temperate coniferous forest and 3 per cent of temperate broadleaf and mixed forests," it says.

The researchers recommend that future studies should focus on elucidating the responses of different vegetation subformations within individual biomes in order to gain finer understanding of vegetation responses to future climate change in the Indian subcontinent.