India is the second most populous, and seventh largest country in the world. It is bounded by the Himalayan Mountains in the north and surrounded by Arabian Sea, the Indian Ocean and the Bay of Bengal. The country includes some of the most unique ecosystems such as the Himalayan Mountains, the vast Indo-Gangetic plains and the Deccan Plateau. India’s terrain leads to a number of different regions with a wide variety of diverse climatic conditions, all of which would face significant but different impacts from climate change. With its large and growing population, and an economy that is closely tied to its natural resource base, India’s population is vulnerable to the impacts of climate change such as changes in forest and water resources and sea level rise. Growing population, rapid industrialization and urbanization coupled with Climate Change will create additional pressures on India’s overall ecology and socio-economic system.

The Fourth assessment report of the IPCC [1] clearly mentioned that climate change is one of the most important global environmental challenges. Its many types of impacts need to be understood and assessed, vulnerabilities need to be addressed and adaptation strategies have to be developed. Climate change is likely to impact all the natural ecosystems as well as socio-economic systems as shown by India’s Initial National Communication on Climate Change (NATCOM I) submitted to the UNFCCC [2]. The latest high resolution climate change scenarios and projections for India, based on Regional Climate Modeling (RCM) system, known as Providing Regional Climate Impact Studies (PRECIS) developed by Hadley Centre and applied for India using IPCC scenarios A2 and B2 shows that an annual mean surface temperature rise by the end of centaury, ranging from 3 to 5o C under A2 scenario and 2.5 to 4o C under B2 scenario  [3].

The Emissions Scenarios: IPCC in its study uses four story lines on the basis of which all predictive assessments are carried out through various models. In simple terms, the four storylines combine two sets of divergent tendencies: one set varying between strong economic values and strong environmental values, the other set between increasing globalization and increasing regionalization. The storylines are summarized as follows:

A1. The A1 storyline and scenario family describes a future world of very rapid economic growth, low population growth, and the rapid introduction of new and more efficient technologies. Major underlying themes are convergence among regions, capacity building, and increased cultural and social interactions, with a substantial reduction in regional differences in per capita income. The A1 scenario family develops into four groups that describe alternative directions of technological change in the energy system.

A2. The A2 storyline and scenario family describes a very heterogeneous world. The underlying theme is self-reliance and preservation of local identities. Fertility patterns across regions converge very slowly, which results in high population growth. Economic development is primarily regionally oriented and per capita economic growth and technological change are more fragmented and slower than in other storylines.

B1. The B1 storyline and scenario family describes a convergent world with the same low population growth as in the A1 storyline, but with rapid changes in economic structures toward a service and information economy, with reductions in material intensity, and the introduction of clean and resource-efficient technologies. The emphasis is on global solutions to economic, social, and environmental sustainability, including improved equity, but without additional climate initiatives.

B2. The B2 storyline and scenario family describes a world in which the emphasis is on local solutions to economic, social, and environmental sustainability. It is a world with moderate population growth, intermediate levels of economic development, and less rapid and more diverse technological change than in the B1 and A1 storylines. While the scenario is also oriented toward environmental protection and social equity, it focuses on local and regional levels.

http://www.grida.no/climate/ipcc/emission/index.htm

Pattern of Climate Change in India

The mean annual precipitation over India as computed from the CRU data was seen to be about 1094 mm and the mean annual temperature was about 22.7°C. The projected climate (average for 2071-2100) for the more moderate B2 scenario is both wetter (an average increase of about 220 mm) and warmer (an average increase of about 2.9°C) compared to the HadRM3 baseline. The corresponding values of increase for the more extreme A2 scenario are about 300 mm and 4.2°C respectively. The mean annual precipitation for the projected values for B2 scenario turns out to be 1314 mm and the projected mean temperature is about 25.6°C. There is considerable geographical variation in the magnitude of changes for both temperature (Figure 1 a) as well as rainfall (Figure 1 b). Northwestern India is likely to become drier, while northeastern India is likely to become much wetter. The temperature increase in northwestern India is also much more than that in the northeast. Southern and southeastern parts of India are likely to experience only a moderate increase in temperature [4].

Figure 1. a, Predicted change in temperature (°C) by 2085, B2 scenario. b, Predicted change in rainfall (mm) by 2085, B2 scenario.

Under changing climate few places are expected to get more rain while some may remain dry. Leaving Punjab and Rajasthan in the North West and Tamil Nadu in the South, which show a slight decrease on an average a 20 per cent rise in all India summer monsoon rainfall over all states are expected. Number of rainy days may come down (e.g. MP) but the intensity is expected to rise at most of the parts of India (e.g. North East). The warming may be more pronounced in the northern parts of India. Many research works show that extremes in maximum and minimum temperatures are also expected to increase.

Regional Projections of Climate Change Over India

Results of regional climate model (RCMs) have shown significant improvements over the global
models in depicting the surface climate over the Indian region, enabling the development of climate change scenarios with substantially more regional detail.

Regional Climate Model results for India predict by the end of the century

• 3-5°C rise in mean surface temperature under A2 scenario and 2.5-4°C under B2 scenario
• 20% rise in summer monsoon rainfall
• Extreme temperatures and precipitations are expected to increase
• Both day and night temperature is going to increase. But nights are going to be warmer
• Regionally within India
  • Northern India will be warmer
  • All states will have increased rainfall except Punjab, Rajasthan, Tamil Nadu where it will decrease
  • Extreme precipitations will increase particularly in west coast and west central India
  • Wetter Forest types in NE and drier in NW predicted to increase

Understanding climate change scenarios for India, and their impacts, is therefore critically important for policymakers to protect lives, as well as the assets upon which India’s economy is dependent. Increasing global warming has caused various climate-related disasters thereby adversely affecting agriculture, health, food security, water resources, and biodiversity as a whole. Under these circumstances India is seriously concerned with the possible impacts of climate change such as:

• Inadequate water availability due to recession of glaciers, and decrease in rainfall in certain pockets of the country.
• Threats to its agriculture and hence to its food security.
• Die back of natural ecosystems such as forest, on which the energy consumption of the rural household depend.
• Adverse impacts on coastal system due to sea level rise.
• Impact on human health due to increase in vector water born diseases and thermal stress.

Climate change will impact across the sectors. The outcome of climate change on the developing and the least developed countries are excessively high, due to three main reasons: fist geographical location, second high dependence of people on natural resources that are highly sensitivity to climate change, third low adaptive capacity due to fewer amounts of resources available to them.

Additional Reading:

India’s Initial National Communication to the UNFCCC (NATCOM I)

High-resolution climate change scenarios for India for the 21st century – K. Rupa Kumar, A. K. Sahai, K. Krishna Kumar, S. K. Patwardhan,  P. K. Mishra, J. V. Revadekar, K. Kamala and G. B. Pant

Variations In The Regional And Seasonal Warming In India – S. K. Dash

FOOTNOTES

• 1. IPCC 2007↑
• 2. India’s Initial NATCOM to the UNFCCC, MoEF New Delhi, 2004.↑
• 3. Rupa Kumar et al. (2006) High Resolution Climate Change scenarios for India for the 21st century. Current Science, Vol 90. No 3, pp 334-345↑
• 4. Ravindranath N. H., N. V. Joshi1, R. Sukumar and A. Saxena (2006) Impact of climate change on forests in India Current Science, VOL. 90, NO. 3, pp 354-361↑