Agriculture is back bone for the countries like India where 54 % public depends upon agriculture as source of income and employment. But threat of global warming has raised serious concerns about its existence in previous years. We are adding 12 million people every year in our already oversized population; where question of food sustainability becomes more pertinent. Besides that falling productivity, erratic monsoon, unpredictable incidence of drought coupled with inherent problems of lack of infrastructure, low adaptation of new technology, foresighted policies to combat shortcomings of our Indian agriculture make the situation more precarious. In this unsteady condition impact of climatic change leading to global warming calls for impact assessment study on agriculture. Such kind of a programme was started by Indian council of agricultural research (ICAR) in year 2004 for studies on impact assessment, adaptation and mitigation options. Currently it includes 23 institutes and more than 100 scientists in this research. The focus areas of the study are divided into two parts; one concentrate on vulnerable areas and other looks for the solution of the same in form of adaptation and mitigation. Vulnerability areas include crops namely wheat, paddy, potato, cotton, pulses and vegetables, plantation crops, livestock, fisheries, soil ecosystems and same are being studied for mitigation and adaptation.
According to some studies conducted, projected impacts have been delineated which shows some different aspects. It is supposed that an increase in CO2 to 550 ppm increases yields of rice, wheat, legumes and oilseeds by 10-20%. But a 1˚C increase in temperature may reduce yields of wheat, soybean, mustard, groundnut, and potato by 3-7% and there will be much higher losses at higher temperatures. Though it is estimated that productivity in most crops would likely to be decreased marginally by 2020 but a looming impact will be there in 2100 when productivity would decrease by 10-40%. But there might be possibly some improvement in yields of chickpea, rabi maize, sorghum and millets; and coconut in west coast. Another projection says that there will be fewer losses in potato, mustard and vegetables in north-western India due to reduced frost damage.
Other projections that are being made in terms of changing behaviour of weather atrocities like floods and droughts that their incidence will be more frequent and more devastating; causing more variability in production. Not only this ecological system would be affected more when there will be considerable effect on microbes, pathogens, and insects. There is greater likelihood of have an effect on fish breeding, migration, and harvests due to increase in sea and river water temperatures. Livestock keeping would be more difficult when there will be increased water, shelter, and energy requirement. Excessive temperature will hamper reproduction efficiency of animals which may result into loss of 1.5 million tons of milk by 2020. Not only this trade imbalance may take place due to in food trade due to positive impacts on Europe and N. America, and negative impacts on us.
Besides these impacts other as well be affecting the agricultural production, like loss % in potato production would soar to 3%by 2020 and close to 14% by 2050. Even there would be drastic change in the length of growing period in rainfed areas which will decrease from 210 days in most areas to 120 days in eastern part of country while in central-south areas where currently LGP is in order of 150-210 days will become of order of 60-120 days 2080.Himanchal apples taste will not be like same as before due to reduction in appropriate chilling requirement. Although coconut yields will increase to the tune of +35(relative yield deviation) in Karnataka and Tamil nadu while +45 in Kerala. Although yields will be deviating negatively in Orissa in order of -35.
Thus conditions are looming large on us. Scientists suggest 2 phases to combat the problem of climate change in form of adaptation and mitigation. How adaptation can be helpful? But before we understand any strategy to these phases we should also understand that agriculture itself is a big contributor to climate change. As a part of the problem it contributes nearly 14% of annual green house gas (GHG) emissions, compared with about 13% by transportation (considered the principal culprit along with deforestation (19%)).
The principal agricultural sources of GHGs include methane emissions from rice fields and livestock, nitrous oxide emissions from fertilized fields, energy use for pumping irrigation supplies and soil and land management practices.
As the first phase for combat programme against climate change adaptation calls for foremost attention. Here I would like to site an example how people of a small village in U.P. are adapting to climate change. For decades, people of Uttar Pradesh, whose population is more than half that of the United States, have been witnessing erratic weather, including increasingly intense rainfall over short periods of time. The rain, combined with heavy mountain run-off from nearby Nepal, which is also seeing heavier-than-usual rains, has inundated villages, towns and cities in the region. Such floods have destroyed homes, crops and livestock, highlighting the fact that the poorest in countries such as China and India are most at risk from climate change.
While world leaders in Copenhagen argue over who should cut carbon emissions and who should pay, experts say low-cost adaptation methods, partly based on existing community knowledge, could be used to help vulnerable farmers.
In the fields of Manoharchak village, for the last three years, they have been trying to change ways to cope with the changing weather with efforts which have included diversifying production from wheat and rice to incorporate a wide variety of vegetables. Villagers here have raised the level of their roads, built homes with foundations up to 10 feet above ground, elevated community hand pumps and created new drainage channels. Farmers are also planting more flood-tolerant rice, giving them two harvests a year where they once had one, and diversifying from traditional crops to vegetables such as peas, spinach, tomatoes, onions and potatoes. The diversity of crops is particularly beneficial when their wheat and rice fail. And the vegetables give them not only a more varied and nutritional diet, but also help in earning an income when excesses are sold.
Increasingly, intense rain means farmers in the region also have to contend with silt deposition from long periods of water-logging in their farms. Here villagers grow about 15 different vegetables as well as rice and wheat as ways to overcome the problem. They plant (vegetable) seedlings in the nurseries and then when the water drains transfer them to the land so there are no delays.
Farmers have also started using "multi-tier cropping" where vegetables like bottle gourd and bitter gourd are grown on platforms raised about 5-6 feet above the ground and supported by a bamboo frame. Once the water-logged soil drains, farmers can plant the ground beneath the platforms with vegetables and herbs such as spinach, radish and coriander.
Warmer temperatures and an unusual lack of rain during monsoon periods in eastern Uttar Pradesh have also led to dry spells. To cope, villagers have contributed to buying water pumps for irrigation, lowering their dependence on rain. As a part of adaptation strategies steps can be taken. We need to assist farmers in coping with current climatic risks by providing relevant information on weather services, by extending agro-advisories, insurance, by opening community banks for seed and fodder in village vicinity. Not only is this but intensification of food production systems is also required. For this strengthening of technology and input delivery systems should be the priority and it should be market linked. Improved land and water management with the technologies for resource conservation and use efficiency are looked at upon as another approach. Policy framework must emphasise regional cooperation by incentives to farmers for resource conservation and use efficiency, pricing of resources, credit for transition to adaptation technologies etc. Strengthening of research for enhancing adaptive capacity is another area worth looking.
Other phase of combat requires agriculture to be the part of mitigation. It can be a part of the solution by mitigating GHG emissions through better crop management, carbon sequestration, soil and land use management, and biomass production. Developing economies are likely to be the hardest hit. In these countries, agriculture is already in crisis; production of food commodities has stagnated and their prices are rising. To ensure global food security, and reverse the process of climate change, will require devising strategies that involve both adaptation of agriculture to climate change and mitigation of GHG emissions from agricultural sources.
Cultivation of rice under flooded conditions is the most important source of methane from agriculture. Globally, over 140 million hectares of rice is grown under flooded conditions and much of this area is in developing countries including India. Methane emissions from irrigated rice cultivation at global level totalled 625 million metric tonne of carbon dioxide equivalent in year 2000.
Changing water management practices from continuous flooding to intermittent irrigation and mid-season drainage reduces methane emissions by over 40%. The rising consumption of livestock products with rising incomes in several developing countries also contributes to GHG emissions.
GHG emissions in livestock systems can be reduced by feeding better quality diets to ruminants, improved fodder technologies that reduce pressure on land (fodder banks, improved pasture species, use of legumes, and others) and using more productive livestock breeds.
Similarly, nitrous oxide emissions are determined by the quantity of nitrogenous fertilisers added to soil to maintain soil fertility and increase crop productivity. The extent of emissions depends on the nutrient use efficiency. Under typical crop management conditions of developing countries, fertiliser use efficiencies are low, leading to high nitrous oxide emissions to the atmosphere.
Improving fertiliser use efficiency of crops through improved management has been a direct concern of traditional agronomic research (even in the absence of climate change concerns) to improve farm productivity and profitability and soil and water conservation. Most of the recommended practices are based on the principle of balanced fertilisation with right source, at the right rate, at the right time, and with the right placement.
Climate change is likely to reduce yields of most crops in long-term. In short-term effects may be small (preliminary results, better field data and models needed).Increased climatic variability could cause significant fluctuations in production even in short-term. Adaptation strategies can help minimize negative impacts. These need greater research, policy and financial support. Costs of adaptation are less understood but likely to be high; costs of inaction could be even higher. Adaptation practices take time to become effective. A crop variety, e.g. takes 10-20 yrs to develop. Need to act now. Mitigation strategies would focus on efficient water management; better quality feed to live-stocks and balanced fertilisation.
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