Rains, Food and Climate Change

Story Staff Reporter Photograph Prasad

Global warming, progressive gradual rise of the earth's surface temperature, is at present being held responsible for changes in global climate patterns. Increase in atmospheric temperature affects the various aspects of global hydrological cycle. As a result, we can expect changes in rainfall, evaporation, and runoff which are projected to cause significant impacts on crops, livestock, fisheries, insects, microbes, etc. 

In recent usage, climate change is often linked to changes in modern climate. Increased human activities in the last century, especially increased fossil fuel usage, industrialization, and land use changes have caused the buildup of greenhouse gases in atmosphere which in turn, are causing changes in the climate. The global mean annual temperature at the end of the 20th century was 0.7°C above those recorded at the end of the 19th century. The 12 warmest years in instrumental record have occurred after 1990. Climate extremes such as droughts, floods, rainfall distribution and snowmelt have increased at several places. Reports also indicate that Himalayan glaciers are receding at an increasing pace. Also, the rate of change in climatic parameters is projected to be faster in the coming decades. The globally averaged temperature of the air above the earth's surface is expected to rise by 1.4 to 5.8°C over the next 100 years.  

The Indian Scenario  

At all India level no significant trend emerges from the study of monsoon rainfall during last 100 years, however there are some regional patterns. West coast, north Andhra Pradesh and north-west India are experiencing increasing monsoon rainfall while east Madhya Pradesh and adjoining areas, north-east India and parts of Gujarat and Kerala are facing a decreasing trend  (-6 to -8 per cent of normal over 100 years). Also rainfall analysis of data of 1140 stations in the country indicated that more than 70 per cent of the stations showed short term fluctuations in annual rainfall for less than 10 years period. 

Surface air temperature for the period 1901-2000 indicates a significant warming of 0.4oC especially along the west coast, central India, and interior Peninsula and over northeast India. However, cooling trend has been observed in northwest and some parts in southern India. A season wise temperature trends indicates that maximum increase in temperature was observed in post monsoon (0.7°C) followed by winter (0.67°C) and then premonsoon (0.5°C) and monsoon (0.3°C). On the other hand the total frequency of cyclonic storms that form over Bay of Bengal has remained almost constant over the period 1887-1997. There are however evidences that glaciers in Himalayas are receding at a rapid pace. 

It is projected, despite considerable uncertainty, that by the end of the 21st century rainfall will increase by 15-31 per cent, and the mean annual surface temperature will increase by 6°C. But, all regions will not be similarly affected - the warming will be more pronounced over land areas, with the maximum increase over northern India and will be relatively greater in winter and post-monsoon seasons. 

Crops and climate change 

India's agriculture is subject to climate variability which is likely to be exacerbated by climate change. The agriculture sector in India contributes to 28 per cent of the total GHG emissions primarily due to methane emission from rice paddies, enteric fermentation in ruminant animals, and nitrous oxides from application of manures and fertilizers to agricultural soils. The emissions from Indian agriculture are likely to increase significantly in future due to our need to increase food production. Although detailed zone wise analysis has not been done, broadly, the wheat production in the Indo-Gangetic plain zones is likely to be affected negatively while the crops in coastal and Island zones are likely to suffer from sea water inundation. Preliminary calculations to quantify the decrease in production of wheat suggest a likely decrease of 4 to 5 million tons with an increase of 1°C increase in temperature throughout the growing season. Productivity of fruit crops will be affected in the hill zones due to rise in temperature and precipitation. It is thus projected that climate change is likely to negatively impact agriculture including irrigation availability, soil health, pests, crop and livestock production.  

Changes in climate are expected impact Kharif season (southwest monsoon) more than Rabi (northeast monsoon) season. During Kharif in 2020, 10 to 15 per cent reduction in rice yield is expected due to increase in temperature and change in rainfall. Consequently, in 2050, 30 to 35 per cent yield reduction and in 2080, up to 80 per cent yield reduction are expected in Tamil Nadu. Aromatic rice, such as Basmati, being more sensitive and high temperature will experience a reduction of test weight, grain elongation and aroma. GIS studies on prediction of suitability of growing ginger in Orissa and West Bengal, now a highly appropriate region, have shown that these areas would turn hostile with rising temperatures of about 1.5° to 2°C. Coconut yields too are likely to be affected and the plains of Karnataka, Eastern Tamil Nadu, coastal Andhra Pradesh, Pondicherry, West Bengal and Assam were found to be hotspots as per HadCM3 model scenarios of climate change. 

Analysis of recent weather data in Himachal Pradesh indicated that the maximum temperature is showing an increasing trend during November to April. This has resulted in a shift of apple belt upwards. In response new areas of apple cultivation have appeared in Lahaul and Spiti and upper reaches of Kinnaur. Apple productivity in Kullu, Shimla as well as overall average productivity of the State has shown declining trend - average State productivity in 1980-81 was 7.06 tons ha^-1 that decreased to 4.65 tons ha-1 in 2004-05. 

Impact on soil, stream flows and pests 

Scientists point towards greater soil conservation efforts in Peninsular and central India because of their projected high runoff and soil losses associated with global climate change. A decreasing trend of runoff and soil loss is projected when we move from tropics to temperate region. Simulation results indicated an increase in mean annual stream flow at several places in 2020 and 2050 under PRECIS RCM scenarios. Though there is increase in annual stream flow, a decrease in monthly stream flow, particularly during summer months (February - June) was projected.

Pest prediction equations in relation to temperature were developed for thrips population in horticultural crops. It was observed that in rose, thrips required 265 and aphids 119 thermal day degrees (TDD) for development under field conditions. 

Climate change and animal husbandry  

A rise of 2-6°C will negatively impact growth, puberty and maturity of crossbreds and buffaloes and time to attain puberty of crossbreds and buffaloes will increase by one to two weeks due to their higher sensitivity to temperature than indigenous cattle. Global warming is likely to lead to a loss of 1.8 million tons in milk production by 2020 and 15 million tons by 2050. The economic losses were projected to be highest in UP followed by Tamil Nadu, Rajasthan and West Bengal. 

Another likely impact may be on the availability of fodder. There is already severe deficit of green fodder and feed for the animals with area under fodder falling, which is having an adverse impact on the productivity of the animals. Also, there may be increase in the vector-borne diseases in animals which in itself a serious threat even today.  

FISHERIES

A rise in temperature as small as 1°C could have important and rapid effects on the distribution, growth, reproductive cycle, mortality of fish and their geographical distributions. Oil sardine fishery did not exist in the northern latitudes and along the east coast before 1976 as the resource was not available and sea surface temperature (SST) were not congenial. With warming of sea surface, the oil sardine is able to find preferential temperatures thereby extending the distributional boundaries. The dominant demersal fish, the threadfin breams have responded to increase in SST by shifting the spawning season to cooler months - 35.3 per cent spawning occurred during the warm months (April-September) in 1980 but the number gradually reduced to 5 per cent during the same season in 2004. A similar trend was observed in other species too. The increase in seawater temperature will however be beneficial in certain instances with likely positive effects on major pelagic fishery such as oil sardine, mackerel and bombay duck. A change in the species composition of fish catch is also expected. 

Recent Climatic patterns have brought about hydrological changes in the flow pattern of river Ganga which has resulted in erratic breeding and decline in fish spawn availability. As a result the total average fish landing in the Ganga river system declined from 85.21 tons during 1959 to 62.48 tons during 2004. In the middle and lower Ganga, 60 genera of phytoplankton were recorded during 1959, which declined to 44 by 1996, while during the same period zooplankton diminished from 38 to 26. A number of fish species, which were predominantly only available in the lower and middle Ganga in 1950s, are now recorded from the upper cold water stretch upto Tehri. Also, in recent years Indian Major Carps are maturing and spawning as early as March with its breeding season extending from 110-120 days (pre 1980-85) to 160-170 days (2000-2005). As a result, it has been possible to breed them twice in a year at an interval ranging from 30-60 days. A prime factor influencing this trend is elevated temperature especially in West Bengal where this study has been undertaken, where average temperature has increased in the range of 0.1 to 0.9°C.

Corals in the Indian Ocean will be soon exposed to summer temperatures that will exceed the thermal thresholds observed over the last 20 years. Annual bleaching of corals will become almost a certainty from 2050. Given the implication that reefs will not be able to sustain catastrophic events more than 3 times a decade, reef building corals are likely to start disappearing as dominant organisms on coral reefs between 2030 and 2040 and the reefs are likely to become remnant between 2050 and 2060 in the Gulf of Mannar. 

IPCC recently synthesized all available global information on this aspect in its recent assessment, and concluded that sea level will rise by 0.18 to 0.59 meters by 2100. If such sea level rise takes place in India, impacts on the livelihood of coastal communities will be considerable with vast stretches of coastal lands submerged, making them unsuitable for upland crops and increasing the salinity in aquifers.  

Coping with the changing climate 

The agricultural strategies to manage climate variability should consist of both short term and long term strategies. The short term strategies include the use of available drought/heat tolerant varieties, water harvesting and efficient use of rain water and irrigation water and proven agronomic practices that release minimum greenhouse gases, etc. The long term strategies include development of varieties of crops and improved breeds tolerant to extreme weather situations through use of frontier technologies, development of resource conservation technologies for different agro-climatic zones that use less water and energy and evolving socio-economic safety nets like weather insurance. In addition, an early warning system of climatic risks, and prior development of region specific responses will be useful.

Heat tolerant varieties of crops may be developed in addition to augmenting production; improving land-use and natural resource management; building a risk management through early warning system and crop insurance; establishing regional food security programmes and raising capacity; and recycling waste water and solid wastes. In the specific case of wheat, adaptations such as change in planting dates and crop varieties could help in reducing impacts of climate change. In fact the losses could be minimized to 1-2 from 4-5 million tons if a large percentage of farmers changed planting time. This may, however, not be easy to implement due to constraints associated with wheat planting time in rice-based cropping systems.  

In the animal husbandry sector the optimal size of livestock population of the country needs to be determined based on the projected requirement of livestock products, availability of feed and fodder resources, land resource availability and environmental sustainability. The estimated requirement of milk, meat and egg by 2020 would be about 160.0 million tonnes, 10.58 million tonnes and 90 billion, respectively. The strategies for regulating the cattle population without affecting the overall production target are (a) selecting high producing animals using marker assisted selection for developing elite herds (b) improving the production potential of animal genetic resources (c) increasing per animal productivity through improved breeding, feeding and health care, (d) enhancing the supply of quality fodder seeds, (e) integrating and strengthening the linkages between the Departments of Agriculture, Animal Husbandry and Environment and Forests. The National Project for Cattle and Buffalo Breeding programme which is already in place seeks to increase the productivity of animals. Despite India being blessed with a very large animal population, productivity is very low - less than half of the world average and about 10 per cent of what is being achieved in Israel. The focus is on artificial insemination especially of our indigenous breeds in cattle which have the capacity to bear stress whether it is heat, humidity or diseases. As far as control of animal diseases is concerned, India is now free from the rinderpest, but the major challenge is to fight the foot and mouth disease which is causing severe economic losses to the country.  

For sustaining production and productivity, the fisheries sector may be able to adapt to Climate Change (i) by designing fuel efficient fishing craft & gear, (ii) by developing resources specific fish harvesting techniques for emerging new fishery, (iii) acclimatization of commercially available cultivable species to the Climate Change in freshwater, coast..: and marine ecosystems, and (iv) identifying new candidate species for aquaculture having more adaptability towards changes in salinity and temperature regime. Research studies on the possible impacts of climate change on fisheries and aquaculture are in progress in the Central Marine Fisheries Research Institute (CMFRI), Kochi and Central Inland Fisheries Research Institute (CIFRI), Barrackpore covering the coasts and 14 major river systems flowing through 13 agro-climatic zones of India. The productivity of the inland fishery sector is very low, thus additional stress needs to be laid to tackle the problem by increasing productivity in reservoirs, canals, tanks and ponds. Also, while the coastal areas have been over-exploited, there is hardly any exploitation of deep sea marine resources. A proactive deep sea marine fishing policy needs to be in place so that EEZ is better exploited. For example, tuna fishing is a profitable venture and conversion of the traditional craft into long-line tuna vessels has been fairly successful.  

Way Forward

Improved land use management and water management is crucial. 16 tons of soil per hectare per annum is getting eroded. Out of this, 29 per cent is going to the sea, and the rest is getting deposited in the river beds/fields. Agricultural conservation in such situations is imperative. One such measure would include laser levelling. In western Uttar Pradesh 22 laser levellers were undertaken each costing about Rs 4 lakh. Once leveled, saving of water is to the tune of about 30 per cent, thus leading to more efficient utilisation of water. Also, actual cropped area goes up by about 3 per cent. Another method is what the farmers in Haryana follow - the practice of raised bed cultivation which saves water and fertilizer apart from inhibiting the growth of weeds. Measures are needed to check the decline in ground water table. As per the latest assessment of ground water resources carried out jointly by CGWB and the State Government Departments in 2004, out of 5723 assessment units (blocks/talukas/ watersheds) in the country, 839 units are ‘over-exploited’. 226 units have been categorized as ‘critical’ and 550 ‘semi-critical’. Several measures have been initiated by the Ministry of Water Resources to check the decline of ground water levels through augmentation of ground water resources which include preparation of manuals and guides on various aspects of artificial recharge to ground water; preparation of concept report entitled ‘Master Plan for Artificial Recharge to Ground Water’- an area of about 4.5 lakh sq. kms. has been identified as suitable for artificial recharge to recharge about 36500 million cubic meters of ground water; implementation of 165 demonstrative artificial recharge schemes in 27 States/UTs during 9th Plan aimed at popularizing cost-effective recharge techniques suitable for different hydrologic/hydro-geological settings in the country; demonstrative scheme on ‘Rainwater Harvesting and Artificial Recharge to Ground Water’ under implementation in identified areas in the States of Andhra Pradesh, Karnataka, Madhya Pradesh and Tamil Nadu; artificial recharge studies being taken up in the XI Plan in priority areas such as over-exploited and critical assessment units, urban areas, etc.; scheme for artificial recharge through dug wells in 1180 over-exploited/ critical/semi-critical areas in the States of Andhra Pradesh, Gujarat, Karnataka, Madhya Pradesh, Maharashtra, Tamil Nadu and Rajasthan to provide sustainability to the dug wells; and, institutions of 'National Water Award and Bhoomijal Samvardhan Puraskars aimed at encouraging local bodies/ non-governmental institutions for adoption of innovative practices of ground water augmentation through rainwater harvesting/ artificial recharge thrpugh peoples participation. 

The most vulnerable section in climate change scenario will be the rural poor, especially the women, children and the old, facing scarcity of water, reduction in yield and mal­nutrition. A force of 'Climate Risk Managers' may be created at all levels. At the village level/block level, they should be able to communicate the strategies required to manage climatic risks on a real-time basis to the farmers. At the same time they should be able to liaise with other related functionaries, including National Disaster Management Authority, Indian Meteorology Department and Department of Agriculture and Animal Husbandry, and insurance officials at district and State levels. 

The National Action Plan on Climate Change envisages, among many other actions, effective disaster management strategies, strengthening communication networks and disaster management facilities at all levels and protection of coastal areas through focusing on coastal protection and early warning system. There are Eight National Missions constituted under the Prime Minister's Council, which form the core of the National Action Plan, representing multi-pronged, long-term and integrated strategies for achieving key goals in the context of Climate Change. The Missions are National Solar Mission; National Mission for Enhanced Energy Efficiency; National Mission on Sustainable Habitat; National Water Mission; National Mission for Sustaining the Himalayan Eco System; National Mission for Green India; National Mission for Sustainable Agriculture; and the National Mission for Strategic Knowledge for Climate Change. The objective of the Missions is to enable the nation to adapt to climate change and enhance the ecological sustainability of our development path.  

Endnote

Although the problem of climate change is global, we need the local solutions, and particularly they are very important for a country like India where food security is a prime concern for our large population of one billion which already we are, and in the next few years our population will continue to be growing and we would be basically depending more on agriculture for achieving our food security. Agriculture is the backbone of our food security. Out of 75 million persons added world over to the ‘hungry’ during 2007, over 30 million are from India. Since the problem of climate change is a current living reality, we need to learn urgent lessons from recent floods; droughts, high temperatures and changes in sea level. Climate change is a reality with limited response options available - mitigation, and adaptation. India needs is adaptation with a total of 141 million hectares of cultivable land out of which 85 million hectares or 60 per cent falls under the rain­fed and dry land area category. Adaptations can be of 4 types - farm level, technological, social and institutional adaptation. Cropping systems and agronomic interventions like soil conservation, crop rotation, intercropping, and zero tillage along with the promotion of less water demanding crops needs to be underway.