Dr. Banarsi Lal
Agriculture is the mainstay of the Indian economy,contributing to food security and employment of rural households.Climate variability has badly affected this sector and the situation may be worsen in future.India has a wide range of climatic conditions.Climate change has significantly affected global agriculture in the 21st century and the Intergovernmental Panel on Climate Change(IPCC) assessment report indicates that most countries will experience an increase in average temperature ,more frequent heat waves ,more stressed water resources desertification and periods of heavy rainfall.The past three decades have been the warmest in the history ,with each decade being warmer than the preceding period.Climate variability and change have always presented a threat to food security through their effect on rainfall,soil moisture and production. The Northern region of the country experiences extreme winters whereas in Southern peninsular region tropical conditions prevail. The North-eastern regions experience hot and humid climate whereas the North-western regions are characterized by dry and arid climatic conditions. Rainfall during the monsoon season is the major element of the Indian climate and continues to be the main source of water for the rainfed agricultural regions in the country. Variability in monsoon related weather and climatic conditions is considered as the primary cause of spatial and temporal fluctuations in agricultural crops yields. The difference in minimum and maximum temperatures above or below the optimum value affects plant physiological conditions such as respiration, water requirement and growth, thereby affecting crops yields. Extreme weather conditions such as flash floods, droughts, heat and cold waves, cyclones, hail storms, frost etc. always affect the agricultural production. Even subtle fluctuations in weather conditions during critical phases of crop development have substantial impact on yields. As most of the cultivated land in India is rain fed and agricultural production is mostly dependent on the monsoons, agricultural productivity and the well being of the Indian farmer is sensitive to climatic variability. On the one hand, agriculture sector is affected by the climate change; on the other hand, this sector can join hands with other sectors in controlling emission of Green House Gases (GHGs). Risks to the agricultural system from changing climatic conditions can be identified at threelevels: the crop level, the farm level and at the food system level.
Climatic variability directly impacts crops yields and also affects soil quality; water resources; insect- pests, diseases and weeds, etc. further aggravating the impact on the cropping system, thereby reducing the yield per hectare of land or per unit of livestock at the farm level. At the crop level, in the short term, increase in carbon dioxide (CO2) concentration is likely to compensate the negative effect on yields due to increase in temperature, but as temperature increases further, it would result in yield losses. Most crop studies have predicted a decrease in the crops yields with an increase in temperature. Also adverse temperature and moisture conditions affect the quality of food grains. Climate change is also likely to have significant effect on the quality of plantation and cash crops such as cotton, fruits, vegetables, tea, coffee, aromatic & medicinal plants, etc.
It has been observed that adaptation measures can reduce negative impacts of global warming and climate change.These measures include alternative crops,intercropping crop varieties,use of drought tolerant varieties,employing irrigation,human migration,changing planting dates,diversification in agriculture etc.The damage to crops caused by pests, pathogens and weeds increases due to increase in temperature. It has been observed that with rise of 2 degree C of atmospheric temperature, 15-17% of wheat and paddy yields are decreased. Change in climate is likely to bring about a change in the population dynamics, growth and distribution of insects and pests thereby, disturbing crop-pest balance. Drought conditions would increase pathogen and insect survival rate due to change in plant nutrient level and decrease in plant defense system. These changes could lead to enormous crop losses in altered environment. The impact of climate change causes in global warming, changes in precipitation patterns, increased frequency of flash floods, land sliding, rise in sea level etc.would affect the water balance and water quality in different parts of the country. Changes inrainfall patterns can cause water shortages in some regions which, combined with thermal stress due to higher mean temperature, can adversely affect crops. Moreover, change in precipitation patterns and variation in temperature may degrade soil quality, reduce soil moisture content and affect micro biodiversity, which in turn affect crop growth. An increase in temperature also increases evapotranspiration, thereby lowering groundwater table and adversely affecting irrigation potential. At some places, increased surface temperature coupled with reduced rainfall may lead to accumulation of salts in upper soil layers. Also, a rise in sea level associated with increased temperature may lead to salt-water ingression in the coastal lands.
Impact of climate change on livestock are felt in the form of elevated body temperatures, increased respiration rates, decrease in feed intake, etc. Indirect impact would be observed in the form of reduction in grazing land and water availability, decline in available cattle feed, emergence of new diseases, etc. Increase in temperature would impact animal production and profitability in dairying due to lower feed intake, milk production and reproduction. Although small ruminants are more tolerant to climatic extremities than from other farm animals, yet empirical evidences indicates adverse impact of heat and cold stress on the growth, production and reproduction performance of these animals. Besides being susceptible to increased heat stress from climate change, the livestock is also exposed to the risks associated with extreme events. India is among 27 countries that are most vulnerable to increase in the frequency and intensity of extreme events such as heat waves, storms, droughts, floods, land sliding etc. Severe drought conditions are likely to affect livestock due to decline in feed and fodder availability and also water shortages. The impact of climate change induced decline in pastoral land would further aggravate the severe constraints on livestock farming. Changes in the climate would also affect the fisheries sector in many ways. Climate change would induce changes in the abundance and distribution of exploited species. These changes would increase further with the degree of severity of extreme events, such as changes in floods and storms, which in turn affect fishing operations and infrastructure. Climate change would also indirectly affect aquatic habitats, ecosystem productivity and the distribution and abundance of aquatic competitors and predators/diseases thereby affectingthe livelihood and food security of fishing communities. It has already been observed that the breeding of the Indian major carps as well as the distribution of important fish species and planktonhas been affected due to changes in temperature and rainfall patterns over the catchments of the Ganga river.
Agricultural sector releases a number of Green House Gases (GHGs) into the atmosphere. These GHGs include Methane, Carbon dioxide, and Nitrous Oxide. Digestion process of ruminants,application manures and wetland rice cultivation are the main contributors to Methane emissions. Use of nitrogenous fertilizers causes Nitrous Oxide emissions. Carbon dioxide emissions arise mainly due to the use of diesel pumps in irrigation. Other sources of carbon dioxide include burning of agricultural wastes, burning of biomass, microbial decay etc. Risks associated with climate change threaten livelihood opportunities within the food production sectors mainly in two ways: Firstly, increase in frequency and intensity of extreme weather events would expose the agricultural sector to greater risks to productivity resulting in loss of revenue and secondly, changing weather and precipitation patterns would require expensive adaptation measures such as relocating crop cultivation, changing the cropping pattern and increase in use of agro-inputs such as feed, fertilizers and pesticides which may lead to economic denigration and job loss. IPCC (2007) projects that small landholder and subsistence farmers, pastoralists and artisanal fisher folk will suffer most due to the complex and localized impacts of climate change. While the lack of sufficient income to purchase food is a major factor contributing to food insecurity, hunger itself contributes to poverty by lowering labour productivity, reducing resistance to disease and depressing educational achievements. In some areas where livelihood sources are limited, decrease in crop yields may threaten famines, or where loss of landmass in coastal areas is anticipated, migration might be the only solution. Another noteworthy dimension of the problem is the likely implications for global and domestic trading regimes and market prices of farm inputs and outputs under the changing climate scenarios. The agriculture and allied sectors in India are exposed to potential risks arising from climate variability and climate change induced stresses. These risks coupled with the existing vulnerabilities such as poverty, high population density, depletion of important natural resources, shrinking cultivable land, insufficient rural infrastructure, etc. are expected to exacerbate the stress on Indian agriculture through a range of direct and indirect impacts.There is need to put more efforts in consolidating and implementing policies particularly those that prevent destruction of natural environments and ensure that crop insurance as a risk coping mechanism has a solid framework that can help to enhance its uptake by farmers in different agro-ecological zones.
(The writer is Chief Scientist & Head, KVK Reasi, SKUAST-J)
