CLIMATE CHANGE IMPACTS

3.0 CLIMATE CHANGE IMPACTS

The Working Group II Report of the IPCC assessing the Impacts, Adaptation, and Vulnerability concludes, inter alia, that the global average surface temperature has increased by 0.6 ± 0.3 0C over the 20th century; and that, for the range of scenarios developed in the IPCC Special Report on Emission Scenarios (SRES), the global average temperature is projected by models to warm 1.4 to 5.8 0C by 2100 relative to 1990. It also concludes that the globally average sea level is projected by models to rise 0.09 to 0.88 m by 2100. These projections indicate that the warming would vary by region, and be accompanied by increases and decreases in precipitation. In addition there would be changes in the variability of climate, and changes in the frequency and intensity of some climate phenomena. Many human associated systems sensitive to climate change include water resources, agriculture and forestry; coastal zones and marine system; human settlements, energy, and industry; insurance and other financial services; and human health. The vulnerability of these systems varies with geographical location, time, and social, economic, and environmental conditions. Natural system can be specially vulnerable to climate change because of limited adaptive capacity. Some of these systems may undergo significant and irreversible damage. Natural system at risks include glaciers, coral reefs, mangroves, tropical forests, polar and alpine ecosystems etc. While some species may increase in abundance or range, climate change will increase existing risks of extinction of some more vulnerable species and loss of biodiversity.

The vulnerability of human societies and natural systems to climate extremes is demonstrated by the damage, hardship, and death caused by events such as droughts, floods, heat waves, avalanches, and windstorms. While there are uncertainities attached to estimates of such changes, it is however established that the geographical extent of the damage or loss, and the number of systems affected, will increase with the magnitude and rate of climate change. The effects of climate change are expected to be greatest in the developing countries in terms of loss of life and relative effects on investment and the economy. Many regions that are vulnerable to climate change are also under pressure from forces such as population growth, resource depletion, and poverty.

India could be more at risks than many other countries from changes in temperature and sea level. Models predict an average increase in temperature in India of 2.3 to 4.8 0C for the bench mark doubling of carbon dioxide scenario (Lonergan, World Bank Technical Paper No.402, 1998). Temperatures would rise more in Northern India than in Southern India. In the North Indian Ocean, under a doubling, the average number of tropical disturbance days could increase from 17 to 29 a year (Haarsma et.al Climate Dynamics, Vol.8, 1993); while, without protection, approximately 7 million people would be displaced, and 5,760 Km2 of land and 4,200 Km of road would be lost (Asthana, JNU, New Delhi, 1993). The dominant cost would be the land loss, accounting for 83 percent of all damages. For the same CO2 doubling scenario, a crop simulation study estimates that wheat yields could decrease between 28 and 68 percent (Rao and Sinha, Impacts of climate change on Stimulated Wheat production in India, 1994). Even allowing for adaptation options, agricultural losses could be significant. The loss in farm revenues is estimated at 9 to 25 percent for a temperature rise of 2 to 30C (Kumar and Parikh, World Bank Technical Paper No.402, 1998)

.Figure 30, illustrated above indicates the assessment of the Working Group II, of the IPCC, on the climate system. Human activities that change the climate expose natural and human systems to an altered set of stresses or stimuli. Systems that are sensitive to these stimuli are affected or impacted by the changes, which can trigger autonomous, or expected adaptations. These autonomous adaptations will reshape the residual or net impacts of climate change. Policy responses in reaction to impacts already perceived or in anticipation of potential future impacts can take the form of planned adaptations to lessen the adverse effects or enhance beneficial ones. Policy responses can also take the form of actions to mitigate climate change through greenhouse gas emission reductions and enhancement of sinks.

Further, in the Indian context, climate change could represent an additional stress on the ecological and socioeconomic system that are already facing tremendous pressure due to rapid urbanization, industrialization and economic development. Moreover, as our economy is closely linked to our natural resources, India is considerably vulnerable to the impacts of climate change. A study conducted jointly by the Indian Agricultural Research Institute, New Delhi and Central Institute of Dryland Agriculture, Hyderabad, stated that in the current scenario of global climate change, the effect on kharif season is expected to be less than to rabi season. Rainfall in rabi season will, however, have wider uncertainity. Kharif rainfall is likely to increase by as much as 10 percent. Further, the study stated that the onset of monsoon over India is projected to be delayed and often uncertain.

A case study of Orissa and West Bengal (IPCC-1992) estimated that in the absence of protection, a one meter sea level rise would inundate 1700 Km2 of predominantly prime agricultural land. The 1999 tropical cyclone that hit Orissa resulted a death toll of about 10,000, clearly demonstrates the extreme significance of impacts related to climate variability. The low lying and densely populated Indian coastline extending to about 6500 Kms remains highly vulnerable to any sea level rise.

On the agricultural front, India, whose 30 percent of the total Gross Domestic Product, is accounted to agriculture and allied activities, climate variability plays a sensitive role. Agricultural productivity is sensitive to broadly two classes of climate induced effects: a) direct effects from changes in temperature, precipitation, or carbon dioxide concentrations, and b) indirect effects through changes in soils, distribution and frequency of infestation by pests, insects, diseases or weeds. Studies predict that rice and wheat yields could decline considerably with climate changes in India.