Among the 35 biodiversity hotspots located across globe, The Himalaya is home to the world’s highest mountains and pristine landscapes which harbour a huge biodiversity. The unique climate and topographic regimes allow it to support a plethora of species. However, climate change especially rising temperatures pose a significant threat to this highly fragile montane ecosystem. This makes investigations on the possible impacts of climate change on this region of particular interest to environmentalists and conservationists. Such an investigation undertaken by Irfan Rashid from the Department of Earth Sciences, University of Kashmir in collaboration with a team of scientists from the Indian Institute of Science (Bangalore) and Jawaharlal Nehru Technological University (Hyderabad), yields a very interesting view of the future of this region.
The study set out to accomplish three goals: one, to map the present distribution of vegetation types (in other words, the types of plants) growing in this region; two, to examine changing climate signals from meteorological data; and three, to predict the vegetation distribution and composition of this region for the rest of this century. The study area is a roughly 200,000 km2 stretch is a part of the north-western Himalaya in Kashmir.
The study has revealed that between 1980 and 2000, minimum temperatures in this region rose faster than maximum temperatures with an insignificant decrease in precipitation rates. Projected values of maximum and minimum temperatures from both stations indicate an increase of 4 to 7°C by the end of century. Precipitation, however, is not expected to change significantly. With regard to changes in vegetation distribution and composition, the results of simulations indicate that most areas of rocky, icy or polar deserts today could be replaced with shrub land, tundra and/or boreal evergreen forest by the year 2035. Besides this, temperate evergreen forest regions are likely to be colonized by temperate deciduous forest, and temperate evergreen broadleaf forests and mixed forests may replace open shrub lands.
In order to map the current vegetation in this region, the researchers extracted a NOAA-AVHRR (National Oceanic and Atmospheric Administration – Advanced Very High Resolution Radiometer) map for the study area. Observed meteorological data from 1979 to 2010 on temperatures, stream flow and precipitation were collected from IMD for Pahalgam and Gulmarg.
Meteorological projections were made for 3 climate scenarios: A1B SRES, RCP-4.5 and RCP -8.5 were used to predict the fate of vegetation by the end of 21st century. As for what these scenarios signify, Rashid says, “In the year 2000, the Intergovernmental Panel on Climate Change (IPCC) developed the global and regional emission path ways in its Special Report on Emissions Scenarios (SRES). It developed four families of emission pathways, namely A1, B1, A2 and B2 based on different socio-economic development assumptions. The A1B scenario is representative of a future world that emphasises very rapid economic growth with a balanced emphasis on all energy sources. A1B scenario is particularly significant as it is often quoted as the “business-as-usual” scenario.”
Since the A1B scenario was developed in 2000 by the Intergovernmental Panel on Climate Change (IPCC) in its Special Report on Emissions Scenarios (SRES), its underlying economic and policy assumptions may be outdated and invalid. “In recent years, the scientific community has developed a set of new-emission scenarios termed as representative concentration pathways (RCPs). These scenarios are formulated such that they represent the full range of stabilization, mitigation and baseline emission scenarios available in current literature”, adds Rashid.
Another interesting find by the research team showed that savannahs (steppes) may also invade certain of these areas. The end of the century could see the widespread growth of savannahs/steppes, and the reappearance of temperate evergreen coniferous forests as well as shrub lands.
The predictions listed in this study were obtained through IBIS (Integrated Biosphere Simulator) simulations. According to Rashid, IBIS is one of the classical Dynamic Global Vegetation Models (DGVMs), which are numerical models typically representative of terrestrial ecosystem dynamics in response to environmental changes.” Rashid further states that DGVMs are known to be one of the most advanced tools for assessing the impact of climate change on terrestrial ecosystems including the forests. However, for a geographical region like that of the Himalaya-a data scare expanse, the work is particularly challenging as it requires extensive input parameters related to climate, soils and topography, along with ground-based vegetation observations for model validation.
The projected climate and vegetation changes predicted by this research effort conclude that climate change is likely to cause major transformations in the vegetation of the Himalayan regions of Kashmir. The altered vegetation distributions may also jeopardise services and products unique to the livelihoods in this region. The carbon stocks present in the region at the moment may also undergo quite a bit of change with gradual changes in the vegetation pattern.
About the authors
Irfan Rashid and Dr. Shakil Romshoo are with the Department of Earth Sciences, University of Kashmir, Srinagar.
Dr. Thatiparthi Vijaya Lakshmi is with the Centre for Environment, Jawaharlal Nehru Technological University, Hyderabad
Dr. Rajiv Kumar Chaturvedi, Dr. N. H. Ravindranath, Dr. Raman Sukumar, Mathangi Jayaraman and Jagmohan Sharma are from the Indian Institute of Science, Bangalore.
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