Deep Impact shallow response | Centre for Science and Environment

Deep Impact shallow response

October 16th, 2001

Climate change will trigger a series of ecological and economic fall-outs for India. Though details remain fuzzy largely due to the apathy of Indian policy makers and scientists.

  • 1998 A high-intensity cyclone destroys two oil refineries under construction, six wind farms and a salt production facility in the coastal regions of Gujarat. Later in the year, heavy monsoon flood the entire country.

  • 1999 The coastal state of Orissa is hit by two successive cyclones, which claim nearly 10,000 lives, and affect 15 million people. The entire coast, which comprises the rice and vegetable belt of the state, suffers large-scale crop loss with damage estimates exceeding US $20 million. An estimated three million homes are leveled by the cyclones, leaving about 7.5 million people homeless.

  • 2000 Over 30 million people in India bear the direct impact of floods. More than 1,500 lives are lost in northeast India alone. Heavy rains and flash floods throw life out of gear and devastate 11 northeastern and eastern states, including Assam, Bihar, West Bengal, and Andhra Pradesh. An estimated 21 million in West Bengal are affected by flooding, as are parts of southern India.

  • 2001 Gujarat experiences heavy rains at the beginning of the monsoon season causing flooding in some districts. The rains are preceded by a severe drought. Orissa is affected once again as unusually heavy monsoon rains inundate about 7,000 villages, affecting a total population of 8.22 million which includes an estimated 2.1 million children. The floods lead to about 1,500 reported cases of diarrhoeal dehydration and outbreak of various water-borne diseases.

Years of consecutive climate-related disasters have brought widespread misery and huge economic loss to India. Is this sheer coincidence, or a fallout of the global climate change? The Indian Meteorological Department (IMD) would like to believe that all is well. SK Srivastava, additional director general, IMD, opined in an interview in June 2001 that recent weather patterns are caused by "inter-seasonal variables". Other scientists disagree. According to M Lal from the Centre for Atmospheric Sciences, Indian Institute of Technology, Delhi, "Climate change is already a reality in India, resulting in changes in rainfall and temperature."

"Even with 0.6°C temperature rise that has taken place in the last 100 years over India, changes are taking place," he says. "The meteorological department says this is not climate change, but we use their data to show that climate change is happening, particularly over the last decade of the twentieth century." It would perhaps be easier to believe Srivastava if his statements were backed by research. Unfortunately, only a handful of scientists have studied the impact of global climate change on the country.

The world scientific community has reached consensus that climate change is human-induced, caused by emissions of greenhouse gases such as carbon dioxide that prevent heat from dissipating into space. The most obvious manifestation of climate change is the rising of average worldwide temperature or global warming. The average annual temperature of the Earth's surface has risen over the last century. Not only is the temperature rising, but the rate of warming itself is increasing too. The global average surface temperature is projected to go up by 1.4°C to 5.8°C by 2100. In ecological terms, this is a very rapid change.

There are several good reasons for India to invest in studying the impacts of climate change on the country. Several global studies have indicated that India is particularly vulnerable to climate change, and is likely to suffer damage to agriculture, food and water security, human health and coastal populations. Like most other developing countries, India is dependent on its natural resources to a large extent. Any adverse impacts on these natural resources, will have repercussion on the nation's economy and widen the gap between the rich and the poor.

Secondly, climate change is not currently seen as an immediate threat by many sections of society in the country, including policy makers and non-governmental organisations. "Climate change in some ways is perceived as a distant issue," says Shreekant Gupta, professor at Delhi School of Economics. "However, some of the serious and very significant impacts on the South and countries such as India could be manifested in the next three to four decades." Awareness of the impacts of climate change on different regions of the country, and sections of society, will create pressure groups to push the government to demand effective global action against climate change under the United Nations Framework Convention on Climate Change (UNFCCC) and its Kyoto Protocol.

Before deciding how much leeway can be allowed in the political give and take that takes place at these global negotiations, it is important that Indian negotiators are fully aware of what climate change may cost the country in the future. The national positions of most industrialised countries are based on a careful cost-benefit analysis of what they stand to gain from not taking action, versus what they stand to lose due to climate change. This allows them to negotiate in their nation's best interest in the global fora. Political positions have inputs from scientists. But in India, there is hardly any interaction between the handful of scientists that work on climate change, and the policy makers who represent the country at global negotiations.

"There is hardly any communication between policy makers and scientists," says SK Sinha, professor at the New Delhi-based Indian Agricultural Research Institute. "It's partly an administrative problem," says Gupta. "When the US government gets a negotiating draft, it makes copies and sends them out. This doesn't happen in India. There are a lot of Indian scholars, especially economists, who could make points or contributions in their individual capacity but there has to be a centralised distribution of relevant information." While scientists blame the government for this
communication gap, and for not encouraging their input in the global negotiations, the government maintains a characteristic silence on the issue, speaking rarely and, even then, under strict conditions of anonymity. According to one such anonymous speaker, "The 'official' Indian focus has always been on the politics of climate change negotiations, not on the actual impacts and adaptation policies to deal with climate change."

"There is no commitment from the Indian government to initiate climate change research," says Ajay Parida, principal scientist, MS Swaminathan Foundation, Chennai. This is reflected globally by the limited participation of Indian scientists in scientific discussions related to climate change. The Intergovernmental Panel on Climate Change (IPCC), a body of scientists that advises UNFCCC, for instance, has only eight scientists participating from India, compared to 227 scientists from the US. Sinha says that given the fact that almost all science advocated by IPCC is coloured by political considerations, the active participation of scientists from India - and from other developing countries - is crucial.

Meanwhile, the lack of public pressure, resulting from the lack of information on impacts, has meant that hardly any politician in the country has recognised climate change as a possible threat to the country's economy. In May 2001, Murli Manohar Joshi, science and technology minister, expressed apprehension over the Antarctic ice sheet melting and the subsequent rise in sea level and acknowledged that coastal India would be at risk. But earlier in April 2001, when discussing the recession of the Gangotri glacier, he said there's no cause for alarm. "Government officials react only to short term stimuli. When there is a conference round the corner they start thinking about these issues," says Gupta. "We need to do our homework. I don't see this happening. The Indian government is always a day late and a dollar short."

India's ecology, agriculture, water resources, biodiversity and its people's health will face the damaging backlash of climate change. Here is a compilation of the possible effects that these changes may bring in their wake.

Coastal chaos
Sea surges will inundate coasts, causing enormous damages

GLOBAL sea level has risen between 10-25 centimetres (cm) during the 20th century due to thermal expansion of the oceans, and melting of Antarctic and Arctic glaciers. The rate of sea-level rise during the 20th century was about 10 times higher than the average rate during the last 3,000 years. Global ocean heat content has also increased since the late 1950s. Sea level rise has significant socioeconomic implications for India (see box : Complex consequences).

Sea level rise will affect many regions of India, but the Andaman and Nicobar Islands and the coral atolls of the Lakshadweep archipelago are most vulnerable.

  • According to a report on the impacts of climate change on India by the Asian Development Bank (ADB), the entire population of Lakshadweep is at peril.

  • According to the ADB study, a one-metre sea level rise will displace approximately 7.1 million people in India, as about 576,400 hectares (ha) of land area is lost, along with 4,200 kilometre (km) of roads. Land loss will account for 83 per cent of all damages.

  • In a case study of the Orissa and West Bengal region, IPCC estimates that in the absence of protection, a one metre sea level rise will inundate an area of 170,000 ha - predominantly prime agricultural land - and displace 0.7 million people. An additional 4,000 km of dykes and sea walls will be required to protect the area.

  • Many big Indian cities are situated on coasts, flood plains and river deltas, supporting a large number of people. Large coastal cities can expect increased flood damage, including that from storm surges and higher wave activity. There will be loss of structures and property. Disappearing shorelines also mean some loss of social amenities.

  • The economic impacts of climate change on a city like Mumbai could be as high as US $48 billion (Rs 2,28,700 crore), while those for Balesore could be US $75 million (Rs 360 crore).

  • Both religious and resort-based coastal tourism will suffer in case of sea level rise. According to the ADB study, Goa, one of the smallest coastal states, will lose 4.32 per cent of its total area. Its famous beaches and tourist infrastructure like beach-based hotels are very vulnerable.

  • Coastal erosion will increase substantially, endangering natural protective features such as sand dunes, mangroves, and barrier islands, and exacerbating flood risk. Many coastal communities depend on fisheries and these will be damaged.

  • Deltas and low-lying coastal areas will be inundated by sea level rise. Increased rainfall during the monsoons will increase the frequency of floods. Areas already prone to floods will suffer more.

  • Most coastal regions, which are agriculturally fertile with paddy fields, are vulnerable to inundation and salinisation.

  • Rising sea levels will put millions of people at greater risk of storm-related flooding. In an area like Bangladesh, where storm surges can reach as far as 200 km inland during intense cyclones, the increase in flood risk could greatly magnify the already high toll associated with such storms. A one metre rise in sea level could inundate 17 per cent of Bangladesh's total land area and displace 11 million people. According to IPCC, a smaller rise of 45 cm would result in a land loss of 1,566,800 ha leading to 5.5 million people being displaced. This will cause a large influx of refugees into India, which will further increase if there is political instability in Bangladesh.

  • In the case of West Bengal, most of the area likely to be lost includes the Sunderban mangrove swamps and reserved forests. This will mean a large loss of wildlife, useful biodiversity and lifestyle.

  • All these factors imply a displacement of large numbers of people, which will lead to rapid urbanisation, straining resources and putting more pressure on civic amenities.

Complex consequences
Multi-dimensional repercusssions of rise in sea level

Calculating and preparing for the effects of climate change is not going to be simple, because when the climate changes, everything changes. For example, as it gets warmer, the polar and glacial ice will start melting; this will mean that the sea level will rise because of the influx of fresh water. How does a rise in sea level affect India? The Asian Development Bank's report on impacts of climate change gives an indication of how complex the ecological and socioeconomic situation in relation to adaptation is, and how serious the effect of climate change is going to be.

- Increased flood damage
- Storm surge
- Shoreline retreat
- Increased sedimentation
- Change in river flow rates
- Higher wave activity
- Increased land subsidence


- Loss of coastal wetlands
- Salt water intrusion
- Evaporation of solar ponds
- Loss of coastal vegetation
- Loss of coastal habitats
- Loss of cultivable land
- Loss of non-commercial biomass

- Loss of human settlements
- Loss of structures and property
- Loss of coastal communities
- Loss of life from increased and sudden storm surges
- Changes in economic activities
- Increased flood insurance costs
- Increased flood control costs
- Loss of social amenities

- Change in coastal zone management practices
- New organisations to handle sea level rise
- Impact on taxes and laws
- Delimitation of maritime boundaries

Productivity peril
Crop yields will decrease substantially posing danger to food security

DEGRADATION of soil and water resources is one of the major challenges for global agriculture. Climate change will further alter agricultural systems with substantial consequences for food production. The risk of reduced food yields is greatest in developing countries, where 790 million people are estimated to be undernourished at present.

In India, it is currently predicted that while overall rainfall may not experience a significant change, the temporal and spatial distribution may change. Central and northern parts of India may get less rainfall while the south-western parts may receive more. Irrigation will suffer if rainfall drops.

  • According to the International Institute for Applied Systems Analysis (IIASA), Austria, India stands to lose 125 million tonnes (or 18 per cent) of its rain fed cereal production potential. If agricultural production goes down, the price of staple food commodities will increase (see table: Plummeting production). 

  • According to a study by the World Bank, a 2ºC rise in temperature along with a seven per cent increase in rainfall will reduce net agricultural revenues by 12.3 per cent for the whole country. 

  • Agriculture in the coastal regions of Gujarat, Maharashtra and Karnataka will be the most negatively affected. 

  • An increase in winter temperature by 0.5ºC will result in a 10 per cent reduction in wheat yield in the high yield states like Punjab, Haryana and Uttar Pradesh. 

  • An increase in minimum temperature from 18ºC to 19ºC will result in a decrease in rice yield of 0.71 tonne per ha, while an increase from 22ºC to 23ºC will result in a decrease of 0.41 tonne per ha. 

  • Even if there is some farm level adaptation, such as the enhanced use of fertilisers and use of different seeds, the loss in farm level net revenue will range from 9-25 per cent for a rise of 2-3.5ºC.

  • According to Lal, there will be some positive effects of climate change due to increase in carbon dioxide in the atmosphere resulting in what is known as "carbon dioxide fertilisation". For example, Madhya Pradesh produces 72 per cent of soybean grown in India with 77 per cent of its area devoted to soybean farming. According to some simulations, a 50 per cent increase in soybean yield could be obtained if atmospheric carbon dioxide concentration doubles. But temperature increase limits this gain; a rise of 1ºC in minimum temperature with doubled carbon dioxide concentration limits the yield increase to 48 per cent. It was found that the positive effects of elevated carbon dioxide almost cancel out with enhanced thermal stress. Deficient monsoon rainfall conditions combined with thermal stress will adversely affect the positive effect of elevated carbon dioxide on the soybean crop in Madhya Pradesh. 
  • Moreover, studies using models that project an increase in crop yields due to carbon dioxide fertilisation are done with the assumption that carbon is a limiting factor in crop growth. This is not the case in India as other nutrients and water may impose more serious restraints.

  • The maximum yield for both rice and wheat are obtained at surface temperatures of 1ºC below the present day climate at current carbon dioxide levels. The yields decline more sharply for a rise in temperature. A 3ºC rise in air temperature almost cancels out the positive effect of elevated carbon dioxide on wheat and rice yields.

  • Climate change will cause a significant increase in pest populations, since generally warmer and moist conditions with longer freeze free periods are highly conducive to them.

  • Changes in forests will alter the configuration and productivity of forests ecosystems. These changes will affect traditional livelihoods, industry, biodiversity, soil and water resources and therefore, agricultural productivity.

Under some climate change models, soil moisture is likely to decline and in turn, reduce forest productivity. For example, teak productivity will decline from 5.40 cubic metre per ha to 5.07 cubic metre per ha. The productivity of moist deciduous forests could decline from 1.8 cubic metre per ha to 1.5 cubic metre per ha.

Health holocaust
More and more people will fall victim to serious illnesses and a host of deadly diseases

THE health impacts of climate change are difficult to calculate since most human health problems have multiple factors. Demographics, environmental degradation and socioeconomic conditions are major factors in illness and disease.

  • Climate related shortages in natural resources like fresh water will exacerbate health problems.

  • According to the World Heatlh Organisation (WHO), there will be a drop in deaths and illnesses related to cold, but those caused by heat will intensify. The number of people dying during heat waves will increase. In urban areas, this will be exacerbated by air pollution.\

  • Climate change will add to the numbers suffering from infectious diseases. Temperature and rainfall affect the distribution of disease vectors and disease-organisms, as well as the vulnerability of populations to these diseases. An example of this can be seen in the case of mosquitoes. Various species of mosquitoes carry malaria, dengue fever, yellow fever, and several types of encephalitis. Cold is usually the limiting factor in mosquito survival, so any increase in minimum winter temperatures is likely to extend mosquito ranges into cooler climes or higher altitudes. 

  • According to the World Resources Institute (WRI), Washington DC, higher temperatures also speed up the life cycles of both the mosquito and the disease organisms they harbour and make adult mosquitoes bite more often. At 30°C, the dengue virus takes 12 days to incubate in the Aedes aegypti mosquito, but only seven days at 32°C. The shorter incubation period translates to a potential threefold higher transmission rate of the disease. Higher temperatures also produce smaller adult mosquitoes that must feed more often to develop an egg batch, which, in turn, increases the chances of disease transmission. Some models suggest that the rise in incidences of malaria globally will be as high as 10 to 20 per cent.  

  • Prey-predator relationships like that of frogs and mosquitoes, which control disease-bearing organisms, may break down leading to an increase in vector numbers. 

  • Water-borne diseases including cholera and diarrhoeal diseases caused by organisms such as giardia and salmonella could also be affected as rainfall patterns change, along with human access to water supplies and sanitation. 

  • According to WHO, global warming will increase the incidence of respiratory and cardiovascular diseases in arid and semi-arid parts of India. 

  • Global warming and increased ultraviolet (UV) radiation will both accelerate the photochemical reaction rates among chemical pollutants and increase ozone concentration in urban areas. Ozone and other photochemical oxidants are associated with many respiratory diseases and cancer

  • Incidences of cataracts and skin cancer will increase due to an increase in UV radiation.
  • It is estimated that the average number of tropical disturbance days (with storms or cyclones) may jump twofold causing illnesses, disease, injuries and loss of lives. In the North Indian Ocean, the average number of tropical disturbance days will increase from 17 to 29 days per year under conditions of doubled carbon dioxide concentration. Cyclone storms approach the 7,000 km long Indian coast from both the Bay of Bengal and the Arabian Sea.

Biodiversity blues
Unable to adapt to rapid changes, many species will die out

  • THERE is concern that genes, species, and ecosystems are being lost due to deforestation. Climate change will aggravate this attrition problem by disrupting delicate relationships within ecosystems. Loss of biodiversity seems to be implicit in most global warming scenarios. Many species considered at risk now will become extinct. 

  • According to IPCC, the range and abundance of plants and animals could change dramatically under changing climatic conditions, and some species are likely to be unable to adapt or migrate to new locations. Most plants and animals can tolerate only a narrow range of ambient temperature. If the temperature varies significantly from this range, normal physiological functioning breaks down.

  • Even more evolved forms of plants and animals that seem to be able to exist in wider climatic ranges need long periods of time to adapt to variations. If change is rapid, they will not be able to adapt, and will die out.

  • Forests will migrate to higher altitudes and transform from drier to more moist types. 

  • Mountain ecosystems are projected to shift to higher elevations, although the rate of vegetation change is expected to be slow and the success with which they colonise new habitats will be constrained by local geographical features. For species that are already at their maximum altitude, this is not an option and extinction seems a distinct possibility.

  • Biodiversity hotspots like the Western Ghats are an important resource base because of their high degree of endemism, biodiversity and productivity. Global warming could put their stability at risk since they cannot move to higher altitudes. 

  • Ecosystems that cannot move northwards at a rate dictated by global warming will be most at risk. These include glacial ecosystems, coral reefs and atolls, forests, Himalayan systems.

  • Unlike many terrestrial ecosystems, coral reef ecosystems appear to be directly threatened by globally increasing atmospheric carbon dioxide. The calcification rates of corals, coralline algae, and coral-algal communities depend on calcium carbonate available in surrounding seawater, and is expected to be reduced by rising atmospheric carbon dioxide. This represents a serious climate-related threat to the functioning of reef ecosystems that will add to the already existing anthropogenic local stresses in places like the Andaman and Nicobar islands.

  • Though coral reefs in these areas will most likely be able to keep up with the rise in sea level, they probably will not survive a rise in sea temperature.

  • Global warming is already contributing to the decline of mangrove forests. Mangroves protect the shoreline, provide wood and fuel. They are also breeding sites for birds, and act as nurseries for fish. At places where urban development and industries are destroying mangroves, the problems caused by sea level rise and thermal stress will be particularly acute there.

  • Salt-water intrusion from sea level rise will damage fresh water ecosystems. Loss of coastal wetlands will result in resident and migrating species having to shift their habitats.

Water woes
Extreme events will adversely affect water resources

  • WATER availability and recharge are expected to be highly vulnerable to climate change. Fluctuation in rainfall will lead to instability in the country's water supply. Besides, climate change may also worsen water pollution.

  • According to M Lal of Centre for Atmospheric Sciences, IIT, Delhi, Indian winters may experience a decline of five to 25 per cent in rainfall. This could lead to drought during dry summer months.

  • Lal predicts that the date of the onset of the summer monsoon over central India could become more variable in future. More intense rainfall spells are projected in a warmer atmosphere.

  • If rainfall decreases, water flow of rain-fed rivers will decrease. This will affect groundwater recharge (see graph: Erratic rains).


    Increase in rainfall might aggravate flood situations, bringing destruction and disease.


  • Since 1871, at least half the severe failures of the Indian summer monsoons have occurred in years of El Niño events. With increasing global temperatures, El Niño events are becoming more frequent and a higher frequency of drought conditions in some parts of India may follow.

  • A rise in sea surface temperatures may be accompanied by an increase in tropical cyclone intensities. According to IPCC, the intensity may go up by 10-20 per cent in the event of a 2-4°C increase in sea surface temperature leading to storm surges along the eastern coast of India.

  • The Himalayan glaciers, which feed many north Indian rivers and are the largest body of ice outside the polar regions, have been shrinking at an accelerated rate. According to Worldwatch, a US-based organisation, about 2,000 glaciers in the eastern Himalaya have completely disappeared in the last century. The Pindari glacier is receding at a rate of 13 metre a year while the Gangotri glacier is retreating at an annual rate of 30 metre. Warming is likely to increase the melting far more rapidly than accumulation of snow.

  • Glacial melt is expected to increase under changed climatic conditions which will lead to an increase in summer flows in some river systems for a few decades followed by a reduction in flow as glaciers disappear. As the rate of glacier melting gets higher, flash floods can be expected.

  • Rivers provide India with hydropower. The last decade has seen rapid deforestation, change in agricultural practices and urbanisation in mountainous region. This has led to frequent hydrological disasters, change in rainfall and runoff, extensive reservoir sedimentation and pollution of lakes. Global warming poses an additional threat to this region, which can harm power production. 

  • l Most of the Himalayan glaciers depend on both summer and winter precipitation, making them more sensitive to temperature variations than any other glaciers. Intense rainfall enhances melting of glaciers and late snowfall in winters does not give enough time for ice-formation. An intensified monsoon and high temperatures thus lead to retreating and thinning of glaciers, increasing the risk of flash floods.

  • River deltas will see incursion of salt water as sea levels rise affecting agriculture.


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