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Home , Extreme weather, Heat wave

CHAPTER-9 HAZARDS , , Frost, Tropical , conditions such as heat – wave and cold –wave. DROUGHT The term drought can be defined by several ways. 1. The condition under which crops fail to mature because of insufficient supply of water through . 2. The situation in which the amount of water required for transpiration and evaporation by crop plants in a defined area exceeds the amount of available moisture in the soil. 3. A situation of no in a rainy for more than 15 days continuously. Such length of non-rainy days can also be called as dry spells. Years in which actual rainfall is ‘above’ the normal by twice the mean deviation or more is defined as years of floods or excessive rainfall. Like , the definition of floods also varies one situation to another and forms one region to other. FROST Frost is water vapor, or water in gas form, that becomes solid. Frost usually forms on objects like cars, windows, and plants that are outside in air that is saturated, or filled, with moisture. Areas that have a lot of often have heavy frosts. TROPICAL , also called or hurricane, an intense circular that originates over warm tropical oceans and is characterized by low atmospheric pressure, high winds, and heavy . Drawing energy from the sea surface and maintaining its strength as long as it remains over warm water, a tropical cyclone generates winds that exceed 119 km (74 miles) per hour. In extreme cases winds may exceed 240 km (150 miles) per hour, and gusts may surpass 320 km (200 miles) per hour. EXTREME WETHER CONDITIONS

A heat wave is a period of excessively hot weather, which may be accompanied by high , especially in oceanic countries. While definitions vary, a heat wave is measured relative to the usual weather in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be termed a heat wave in a cooler area if they are outside the normal climate pattern for that area. A cold wave is a rapid fall in temperature within a 24-hour period requiring substantially increased protection to , industry, commerce, and social activities. The precise criterion for a cold wave is determined by the rate at which the temperature falls, and the minimum to which it falls. This minimum temperature is dependent on the geographical region and time of year.

CHAPTER –10 Modifications of crop microclimate, Climatic normals for crop and livestock production

Relation of weather with agriculture Solar Radiation: It includes light intensity, light quality and duration of sunlight. Out of total radiation received, only 50% in photosynthetically active radiation (PAR) which lies in 400- 700nm range. Rest is UV or IR. Now there is an exponential relation between amount of light intercepted by canopy and Leaf Area Index (Leaf Area/ground area). The sum of these values for individual days is directly proportional to crop yield. Temperature: A term growing degree days is used which is given for a crop from time of flowering to date. Every crop has a temperature range below or above which GDD for that particular day is zero. GDD is the sum of difference of daily temperature and base temperature. So the harvest date is predicted depending on the when the GDD is achieved. Precipitation, Evaporation and Transpiration: There is a relation to calculate the length of growing period which includes Evapotranspiration. We need to know amount of precipitation and crop water requirement. Also transpiration causes cooling so maintains temperature. This prevents crop from damaging. These factors are responsible for proper crop growth and development. If anyone of the factors is affected, the crop will be affected accordingly as in case of heavy rains, high temperatures etc. AGRICULTURE AND WEATHER RELATION Higher CO2 levels can affect crop yields. Some laboratory experiments suggest that elevated CO2 levels can increase plant growth. However, other factors, such as changing temperatures, ozone, and water and nutrient constraints, may counteract these potential increases in yield. For example, if temperature exceeds a crop's optimal level, if sufficient water and nutrients are not available, yield increases may be reduced or reversed. Elevated CO2 has been associated with reduced protein and nitrogen content in alfalfa and soybean plants, resulting in a loss of quality. Reduced grain and forage quality can reduce the ability of pasture and rangeland to support grazing livestock. More extreme temperature and precipitation can prevent crops from growing. Extreme events, especially floods and droughts, can harm crops and reduce yields. Dealing with drought could become a challenge in areas where rising temperatures cause soils to become drier. Although increased irrigation might be possible in some places, in other places water supplies may also be reduced, leaving less water available for irrigation when more is needed. Many weeds, pests, and fungi thrive under warmer temperatures, wetter , and increased

CO2 levels. Though rising CO2 can stimulate plant growth, it also reduces the nutritional value of most crops. Rising levels of atmospheric carbon dioxide reduce the concentrations of protein and essential minerals in most plant species, including wheat, soybeans, and rice. This direct effect of rising CO2 on the nutritional value of crops represents a potential threat to human health. Human health is also threatened by increased pesticide use due to increased pest pressures and reductions in the efficacy of pesticides.

MODIFICATION OF CROP MICROCLIMATE Many vegetable crops do not perform to their full potential in unfavorable condition of environment. Producers can, however, modify the environment a small scale, creating microclimates more suitable for growing high value, warm-season crops. Artificial control of field environment to keep the optimum condition of plant growth and crop production - A practice of environmental control requires a complete knowledge of physiology of plants and physical environment. It is be done through: 1. Controlling wind velocity 2. Controlling heat load 3. Controlling water balance.

CLIMATIC NORMALS FOR CROP AND LIVESTOCK PRODUCTION CLIMATIC NORMALS FOR CROP PRODUCTION Rice Temperature and solar radiation influence rice yield by directly affecting the physiological processes involved in grain production and indirectly through the incidence of pest and diseases. The difference in yield is mainly due to temperature and solar radiation received during its growing season. It requires high temperature, ample water supply and high atmospheric humidity during growth period. Rice tolerates up to 40°C provided water is not limiting. A mean temperature of 22°C is required for entire growing period. If high temperature drops lower than 15°C during the growth phase, the rice yield is greatly reduced by formation of sterile spikelets. The period during which low temperature is most critical, is about 10–14 days before heading. Solar radiation - Low sunshine hours during the vegetative stage have slight ill effect on grain production, whereas the same situation during reproductive stage reduce the number and development of spikelets and thereby the yield. For getting grain yield of 5 t/ha, a solar radiation of 300cal cm2/day is required. A combination of low daily mean temperature and high solar radiation during reproductive phase is good for getting higher yield. Rainfall - Rice requires high moisture and hence classified as hydrophytes. Rice requires a submerged condition from sprouting to milky stage. The water requirement is 125 cm. An average monthly rainfall of 200 mm is required to grow low land rice and 100 mm to grow upland rice successfully. Wheat Optimum temperature for sowing is 15–20°C. At maturity, it requires 25°C. At harvest time, wheat requires high temperature of 30–35°C and bright sunny period of 9–10 hours. Moisture - One ha of wheat consumes about 2500–3000 tones of water. Water deficiency at the heading stage results in shriveled grains and low yield. Maize This crop is best suited for intermediate climates of the earth to which the bulk of its acreage is confined. Temperature - Maize requires a mean temperature of 24°C and a night temperature above 15°C. No maize cultivation is possible in areas where the mean summer temperature is below 19°C or where the average night temperature during the summer falls below 21°C. However, high night temperature also results in low yield. Moisture - Maize is adapted to humid climates and has high water requirements. It needs 75 cm of rainfall during its growth period. The average consumptive use of water by maize is estimated to range between 41 and 64 cm. From germination up to the earing stage, maize requires less water. However, at flowering, it requires more water and the requirement reduces towards maturity.

CLIMATIC NORMALS FOR LIVESTOCK PRODUCTION Direct effects of on livestock The most significant direct impact of climate change on livestock production comes from the heat . Heat stress results in a significant financial burden to livestock producers through decrease in milk component and milk production, meat production, reproductive efficiency and animal health. Thus, an increase in air temperature, such as that predicted by various climate change models, could directly affect animal performance. Indirect effects of climate change on livestock Most of the production losses are incurred via indirect impacts of climate change largely through reductions or non-availability of feed and water resources. Climate change has the potential to impact the quantity and reliability of forage production, quality of forage, water demand for cultivation of forage crops, as well as large-scale rangeland vegetation patterns. In the coming decades, crops and forage plants will continue to be subjected to warmer temperatures, elevated carbon dioxide, as well as wildly fluctuating water availability due to changing precipitation patterns. Climate change can adversely affect productivity, species composition, and quality, with potential impacts not only on forage production but also on other ecological roles of grasslands. Due to the wide fluctuations in distribution of rainfall in growing season in several regions of the world, the forage production will be greatly impacted. With the likely emerging scenarios that are already evident from impact of the climate change effects, the livestock production systems are likely to face more of negative than the positive impact. Also climate change influences the water demand, availability and quality. Changes in temperature and weather may affect the quality, quantity and distribution of rainfall, snowmelt, river flow and groundwater. Climate change can result in a higher intensity precipitation that leads to greater peak run-offs and less groundwater recharge. Longer dry periods may reduce groundwater recharge, reduce river flow and ultimately affect water availability, agriculture and drinking water supply. The deprivation of water affects animal physiological homeostasis leading to loss of body weight, low reproductive rates and a decreased resistance to diseases. More research is needed into water resources’ vulnerability to climate change in order to support the development of adaptive strategies for agriculture. In addition, emerging diseases including vector borne diseases that may arise as a result of climate change will result in severe economic losses.

CHAPTER- 11 , Types of weather forecast, Uses of weather forecasting, Climate change, Climatic variability, Global warming, Causes of climate change and its impact on regional and national Agriculture

Weather forecasting Weather forecasting is the prediction of what the will be like in a particular place by using technology and scientific knowledge to make weather observations. In other words, it's a way of predicting things like cover, rain, , wind speed, and temperature before they happen.

General Public Agriculture including Shipping

forestry and Animal Mercantile & Naval husbandry

Fishing Off shore drilling

Weather forecasting services Mountaineering Defence services

Cyclones, floods and Government and Post Aviation

drought officials Civil & Military

TYPES OF WEATHER FORECAST

Types of forecast Validity period Main users Predictions 1 Short range Up to 72 hours Farmers marine Rainfall distribution, heavy a) Now casting 0-2 hours agencies, rainfall, heat and cold wave b) Very short range 0-12 hours general public conditions, thunder etc. 2 Medium range Beyond 3 days Farmers Occurrence of rainfall, and up to 10 Temperature. days. 3 Long range Beyond 10 days Planners This forecasting is provided for up to a month Indian rainfall. The out and a season. looks are usually expressed in the form of expected deviation from normal condition.

USES OF WEATHER FORECASTING 1. The forecast of the weather events helps for suitable planning of farm. 2. It helps in to undertake or withheld the sowing operation 3. It helps in following farm operation: I) To irrigate the crop or not II) When to apply fertilizer or not. III) Whether to start complete harvesting or to withhold it. 4. It also helps in to take measures to fight frost. 5. It helps in transportation and storage of food grains. 6. Helps in management of cultural operations like plugging harrowing hoeing etc. 7. It helps in measures to protect livestock. CLIMATE CHANGE Alterations to the earth’s atmosphere that occur over much longer periods—decades to millennia—are characterized as “climate change.” While climate change can be caused by natural processes—such as volcanic activity, solar variability, plate tectonics, or shifts in the Earth’s orbit—we are usually referring to changes attributable to human activity when talking about climate change, such as increased emissions. The Fifth Assessment Report from the Intergovernmental Panel on Climate Change (IPCC 2013), for example, found that on average global temperatures increased about 0.85°C from 1880 to 2012, and concluded that more than half of the observed increase in global average temperatures was caused by elevated emissions of carbon dioxide and other greenhouse gases. CLIMATE VARIABILITY While the climate tends to change quite slowly, that doesn’t mean we don’t experience shorter- term fluctuations on seasonal or multi-seasonal time scales. There are many things that can cause temperature, for example, to fluctuate around the average without causing the long-term average itself to change. This phenomenon is climate variability, and when scientists talk about it they are usually referring to time periods ranging from months to as many as 30 years. For the most part, when discussing climate variability, we’re describing natural (that is, non- man-made) processes that affect the atmosphere. For example, the North Atlantic Oscillation (NAO) refers to anomalous changes in atmospheric pressure at sea level that occur near Iceland and the . NAO-positive phases are often associated with above-average storm counts over parts of and the U.S. You’re also likely familiar with the El Niño Southern Oscillation (ENSO) phenomenon near the equatorial Pacific Ocean, where fluctuations of sea surface temperatures typically alternate every few years between a warming phase (El Niño) and cooling periods (La Niña), with a neutral phase in between. Many researchers have found that negative ENSO years are correlated with a higher probability of formation, as well as warmer, dryer weather in northern states. GLOBAL WARMING

Since CO2 is confined exclusively to the troposphere its higher concentration may act a serious pollutant. Under normal conditions with normal CO2 Concentration the temperature at the surface of the earth is maintained by the energy balance of the sun rays that strike the planet the planet and heat that is radiated back into space. However when there is an increase in CO2 concentration the thick layer of this gas prevents the heat from being re-radiated out. This thick

CO2 layer thus functions like the glass panels of a greenhouse or the glass windows of a motor car, allowing the sunlight to filter through but preventing the heat from being re-radiated in outer space. This is the so-called greenhouse effect. Nitrogen and oxygen the main constituents of the atmosphere play no part in the green house effect. But there are approximately 35 trace gases that scientists believe contribute to global warming. Carbon dioxide (CO2) is considered to be one of the most important of these greenhouse gases absorbing most of the heat trapped by the atmosphere. Other gases of special importance in global warming are chlorofluorocarbons (CFCs), methane, nitrous oxide and ozone. Although the average concentrations of these gases are much lower than that of carbon dioxide, they are much more efficient than carbon dioxide at soaking up long – wave radiation. Overall carbon dioxide is estimated to cause almost 60 per cent of the warming effect and CFCs about 25 per cent and the remainder is caused by methane, nitrous oxide, ozone and other trace gases. The Greenhouse effect 1.Nearly all the incoming solar energy arrives extra terrestrially with wavelength less than 4 μm (short wavelength radiation) while the outgoing energy radiated by the earth has essentially all of its energy in wavelength greater than 4 μm (long wavelength or thermal radiation) 2. Essentially all the incoming solar radiation with wavelengths less than 0.3 μm (ultraviolet) is absorbed by oxygen and ozone in the stratosphere. 3. Most of the long wave-length energy radiated by the earth is affected by a combination of radioactively active gases most importantly water vapour (H2O), CO2, N2O and CH4. 4. Radioactively active gases that absorb wavelengths longer than 4 μm are called greenhouse gases. 5. These gases trap most of the outgoing thermal radiation attempting to leave the earth's surface. This absorption heats the atmosphere which in turn radiates energy back to the earth as well as out to space. 6. The greenhouse effect adds 33°C of warming to the surface of the earth i.e. if there was no greenhouse effect the earth would have an average temperature of –18°C or about 0°C. Global Warming and Climate Change Carbon dioxide is a green house gas that is confined to the troposphere and its higher concentration may act as a serious pollutant. Under normal conditions the temperature at the surface of the earth is maintained by energy balance of the sun rays that strike the planet and heat that is reradiated back into space. However when there is an increase in CO2 concentration the thick layer of the gas prevents the heat from being reradiated out. This thick CO2 layer functions like the glass panel of a green house allowing the sun light to filter through but preventing the heat from being reradiated into outer space. Therefore, it is warmer inside the green house than outside. Similar condition is resulted in the troposphere of the earth and termed as Green house effect.

Certain gases in the atmosphere known as green house gases like CO, CO2 and CH4 are able to absorb and emit heat. When sunlight strikes the earth’s surface it warms up emits heat which radiates upwards into space. This heat warms up the green house gases so that they also emit heat some into space and some back down to earth which results in heating up of the earth atmosphere also known as global warming.

CAUSES OF CLIMATE CHANGE 1. Carbon dioxide emissions from fossil fuel burning power plants Our ever increasing addiction to electricity from coal burning power plants releases enormous amounts of carbon dioxide into the atmosphere. CO2 emissions come from electricity production, and burning coal accounts for 93% of emissions from the electric utility industry. Every day, more electric gadgets flood the market, and without widespread alternative energy sources, we are highly dependent on burning coal for our personal and commercial electrical supply. 2. Carbon dioxide emissions from burning for transportation Our modern car culture and appetite for globally sourced goods is responsible for about 33% of emissions. With our population growing at an alarming rate, the demand for more cars and consumer goods means that we are increasing the use of fossil fuels for transportation and manufacturing. Our consumption is outpacing our discoveries of ways to mitigate the effects, with no end in sight to our massive consumer culture. 3. Methane emissions from animals, agriculture such as rice paddies, and from Arctic seabeds Methane is another extremely potent greenhouse gas, ranking right behind CO2. When organic matter is broken down by under oxygen-starved conditions (anaerobic decomposition) as in rice paddies, methane is produced. The process also takes place in the intestines of herbivorous animals, and with the increase in the amount of concentrated livestock production, the levels of methane released into the atmosphere is increasing.

4. Deforestation, especially tropical forests for wood, pulp, and farmland The use of forests for fuel (both wood and for charcoal) is one cause of deforestation, but in the first world, our appetite for wood and paper products, our consumption of livestock grazed on former forest land, and the use of tropical forest lands for commodities like palm oil plantations contributes to the mass deforestation of our world. Forests remove and store carbon dioxide from the atmosphere, and this deforestation releases large amounts of carbon, as well as reducing the amount of carbon capture on the planet. 5. Increase in usage of chemical fertilizers on croplands In the last half of the 20th century, the use of chemical fertilizers (as opposed to the historical use of animal manure) has risen dramatically. The high rate of application of nitrogen-rich fertilizers has effects on the heat storage of cropland (nitrogen oxides have 300 times more heat-trapping capacity per unit of volume than carbon dioxide) and the run-off of excess fertilizers creates ‘dead-zones’ in our oceans. In addition to these effects, high nitrate levels in groundwater due to over-fertilization are cause for concern for human health.

IMPACT OF CLIMATE CHANGE ON REGIONAL AND NATIONAL AGRICULTURE Climate change and agriculture are interrelated processes, both of which take place on a global scale. Climate change affects agriculture in a number of ways, including through changes in average temperatures, rainfall, and climate extremes(e.g., heat waves); changes in pests and diseases; changes in atmospheric carbon dioxide and ground-level ozone concentrations; changes in the nutritional quality of some ; and changes in sea level. Climate change is already affecting agriculture, with effects unevenly distributed across the world. Future climate change will likely negatively affect crop production in low latitude countries, while effects in northern latitudes may be positive or negative. Climate change will probably increase the risk of food insecurity for some vulnerable groups, such as the poor.

Animal agriculture is also responsible for greenhouse gas production of CO2 and a percentage of the world's methane, and future land infertility, and the displacement of local species. Agriculture contributes to climate change by (1) anthropogenic emissions of greenhouse gases (GHGs), and (2) by the conversion of non-agricultural land (e.g., forests) into agricultural land. Agriculture, forestry and land-use change contributed around 20 to 25% to global annual emissions in 2010.