Climate change refers to any change in climate overtime whether due to natural variability or as a result of human activity. Climate change is one of the global burning issues that has shaken the global political arena to focus on this vital issue that may endanger the very existence of mankind and other species on blue plant. Warming has caused melting of polar ice and increase of ocean water levels. It has produced shorter and warmer winters, with earlier arrival of spring temperatures and later onset of winter conditions. Unable to cope up with the current environmental stresses such as drought and water stress, the poor will be vulnerable to climate change and will find it difficult to adapt. The agriculture activities globally contribute about 13.5 % while as India contributes 28 % through agriculture. The impact of climate change on the poorest people, which may exceed five hundred million in India, is rarely the central issue in all the debates on climate change. The central issue for policy makers seems to be the likely impact of any climate mitigation measures on economic growth. However, economic growth alone will not insulate the poor against the adverse impact of climate change. High growth rates in the past decade have not made any significant impact on the quality of life of the poor. The poor in India are already exposed to severe water scarcity, water pollution, fodder and fuel wood scarcity, land degradation desertification, droughts and floods. Warming has caused melting of polar ice and increase of ocean water levels. It has produced shorter and warmer winters, with earlier arrival of spring temperatures and later onset of winter conditions.
Ever increasing emission of green house gasesis a natural processthat plays a major part in shaping the earth's climate. It produces therelatively warm and hospitable environment near the earth's surface wherehumans and other life-forms have been able to develop and prosper. However, theincreased level of greenhouse gases (GHGs) carbon dioxide (CO2),water vapor (H2O), methane (CH4), nitrous oxide (N2O),hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride(SF6), and indiscriminate cutting of trees due to anthropogenic activities hascontributed to an overall increase of the earth's temperature, leading to aglobal warming. According to IPCC, the three main causes of the increase ingreenhouse gases observed over the past 250 years have been fossil fuels, landuse, and agriculture. Agriculture is itself responsible for an estimated onethird of global warming and climate change. It is generally agreed that about25 per cent of the main greenhouse gas, carbon dioxide, is produced byagricultural sources, mainly deforestation and burning of biomass. Most of themethane in the atmosphere comes from domestic forest fires, wetland ricecultivation and waste products, while conventional tillage and fertilizer useaccount for 70 per cent of the nitrous oxides. The Food and AgricultureOrganization has estimated that meat production accounts for nearly a fifth ofglobal greenhouse gas emissions. These are generated during the production ofanimal feeds. Ruminants particularly cows, emit methane which is 23 times moreeffective as global warming agent than carbon dioxide.
Table-1:-Major contribution of Green House Gases
|Gas||% contribution||Global warming potential|
Reduced crop yield:-Agriculture willbe impact by climate change in several ways. There will be reduced crop yield.For example, an increase of temperature from 1 to 4o C can reduce grain yieldof rice by 0-49% potato by 5-40%, green gram by 13-30%. The climate changeimpact on the productivity of rice in Kashmir (India) has shown that with allother climatic variables remaining constant, temperature increases of 1 °C, 2°C and 3 °C, would reduce the grain yield of rice by 5.4%, 7.4% and 25.1%,respectively. Soil temperature affects the rates of organic matterdecomposition and release of nutrients. At high temperatures, though nutrientavailability will increase in the short-term, in the long-run organic mattercontent will diminish, resulting in a decline in soil fertility. Climate changecan shorten rabi season and decrease yield.
Impact on temperatefruit crops:- Temperate regions ofthe world are going to be the first causality in view of the ever increasing global mean temperature thatmay effect the livelihood of agrarian temperate countries to a larger extent.The potential effects of global warming are on chill requirement, floweringtime, risk of frost, length of growing season, maturity/ harvest, fruitquality. The predominant effect of global warming is increase inevapotranspiration which will increase the demand for irrigation. Higher temperature affects pollen viability and hasresulted in flower bud drop in peach and apricot. Prolongedexposure to direct sunlight causes a rise in surface temperatures in fruit andthus results in rapid ripening and other associated events. One of the classicexamples is that of grapes, where berries exposed to direct sunlight ripenfaster than those ripened in shaded areas. Temperature is the most significantfactor affecting antioxidant activity in vegetables and fruits. Generally, risein temperature accelerates initiation reactions, and hence results in declineof existing and augmented antioxidant activities. Antioxidants in fruit andvegetable crops can also be altered by exposure to high temperatures during thegrowing season. The authors verified that higher temperatures inclined toreduce vitamin content in fruit and vegetable crops. Many fruits,including apples, cranberries, blue berries and nuts require at least 1000hours below 450 F each winter to produce good yield. Under the highemissions, winter temperature in temperate areas may not be cold enough toconsistently to meet these requirements
Chillingrequirement is very important for temperate fruits for bud formation. Treesdevelop their vegetative and fruiting buds in summer and these buds will remaindormant until they have accumulated sufficient chilling requirement. Howeverdue to the ongoing global warming the temperate fruits failed to receivesufficient chilling requirement which leads to many symptoms like delayed leafformation, reduced fruit set and reduced fruit quality. The increase intemperature causes low viability of pollen grains and ovule, pollen desiccationand death of pollinators. Spring events such as bud break on trees and breedingof toads and birds are happening about 5 days earlier with each decade. Someauthors have reported a trend towards an increased risk of spring frost,although this is not exclusively attributed to climate change, but also to spread of early flowering cultivars orthe expansion of growing areas into region more susceptible to frost.
Shifting in farming areas:- Rising sea levels owing to climate changewould force communities in low line coastal areas and river deltas to move tohigher ground level. Similarly, increasing frequency of droughts due to climatechange would force farmers and pastoralists, who rely on rain fall to raisetheir crops and livestock, to migrate to areas in search of land and water.This migration/ displacement of people would result in direct conflict andcompetition between migrants and established communities for access to land.
Mehraj ud Din Sheikh,Ex-Deputy Director SAMETI, SKUAST-Kashmir.
Dr. H .A. Malik,Asstt Prof. SKUAST-Kashmir and Ex-Consultant Planning Commission, GoI
Dr. Mehraj Ud DinKhanday, Research Scholar, presentlyworking in networking project funded by Department of Science and Technoloy,GoI
Ejaz A Parry,Research Scholar SKUAST-Kashmir.