Parta causes and impacts of drought in bangladesh drought is one of the main problems for many nations, and the severity of such issue goes big when it comes as obstacle to ensure an optimum agricultural production for a country like bangladesh. Drought is a temporary feature of climate, an aberration. Drought is a slowmoving hazardous event, so the psychological effects of living through this type of disaster are more subtle and last longer than with other natural disasters. The national guidelines for the management of drought have been formulated after a ninestep processtaking on board, through a process of wideconsultation, various central ministries departments, statesunion territories and other stakeholders, including scientific and technical. Inadequate rainfall causes crop failure which lead to famines.
In this chapter, the causes of drought, types of drought, and the propagation of drought as a system dynamic process are discussed. Causes and current understanding congressional research service summary drought is a natural hazard with potentially significant economic, social, and ecological consequences. Many drought definitions are adopted in different fields meteorology, hydrology. Many indices and indicators are available to assist in the quantitative assessment of drought severity. Air circulation and weather patterns also cause drought. A longdrawnout period without rainfall can cause an area to dry out. The severity of the drought is gauged by the degree of moisture deficiency, its duration, and the size of the area affected.
Drought is a normal part of virtually all climatic regions, including areas with high and low average rainfall. The first three categories are referred to as environmental droughts whilst the socioeconomic drought is considered a water resources systems drought loukas and vasiliades, 2004. Drought leads to scarcity of foodgrains akal, water jalkal, fodder tinkal and often all of these trikal. Drought definitions conceptual definitions, formulated in general terms, help people understand the concept of drought. The changes in area of forest by region and subregion are shown in table 1. It describes the issues of drought identification, causes, prediction. Recurrence of drought in nigeria causes effects and report,1 understanding what drought is and its causes, how it has affected north america in the past, and how drought may affect the united states in the future all bear on actions congress may take to prepare for and mitigate the effects of drought. Meteorological drought, agricultural drought, hydrological drought and socialeconomic drought 9.
The distribution of water on the earths surface is not even. Different sets of people have different definitions of drought. Drought is the consequence of anticipated natural precipitation reduction over an extended period of time, usually a season or more in length. Wilhite, director school of natural resources the challenge for early warning systems. Jan 23, 2020 regardless of a drought s stage, there are short and long term consequences with any drought because of nature and societys dependence on water. Projected future aridity is presented based on recent studies and our analysis of model simulations. However, a comprehensive analysis of droughts, including their evolution, complexity, social implications and peoples vulnerability is currently lacking. Droughts pdf download types of droughts and factors the term drought in simple words is the absence of water for a long period of time, at a place where it is considered abnormal as compared to its usual conditions.
This type of drought is defined by a lack of precipitation over a period of time agricultural drought. A drought can last for months or years, or may be declared after as few as 15 days. Meteorological drought results in depletion of soil moisture that almost always has an impact on crop production. A drought is a long period of lowerthannormal precipitation. In practice, drought is defined in a number of ways that reflect various perspectives and interests.
As of midaugust 2019, the drought is classified as a level 2 redclass event by the global disaster alert and coordination system 1. Drought monitoring techniques have a wide range of applicability and importance to address such challenges. In the deserts of the southwest, the average precipitation is less than 3 inches per year. Drought is a creeping phenomenon with no universal definitiondefinitions are region and application impact specific. Causes, effects and control strategies sumit chakravarty 1, s. Table 1 presents definitions for these different types of drought. Drought is among the most damaging natural disasters in the world. Agricultural drought links various characteristics of meteorological or hydrological drought to agricultural impacts, focusing on precipitation shortages, differences between actual and potential evapotranspiration, soil water deficits, reduced groundwater or. Hydrologists define drought as an extended period of less precipitation and stream flow. Several weeks, months, or even years might pass before people know that a. Ohio, who has been in a sports championship drought and moving out of it is headed into a water drought. Causes and consequences of the drought 1 usda climate hubs. This is why the definition is specific to each region.
We have been taking the availability of water very lightly ans using it without any thought to its usage. As overall temperatures increase more water evaporates and severe weather conditions increase. Meteorologists define drought as a prolonged duration without rain. Droughts are natural events that occur in nearly all climate zones but with widely variable characteristics. As of midaugust 2019, the drought is classified as a level 2 redclass event by the global disaster alert and coordination system. Vogt 1 executive summary of part i western cape province in south africa is going through a severe drought. Sep 14, 2018 types of drought include meteorological, hydrological, and agricultural. Natural and manmade disaster and their impact on environment. Drought is a deviation from climate and is quite different from an arid region with low annual precipitation. The water crisis in south africas cape town teaches us theres more at play than just rainfall. Regardless of a droughts stage, there are short and long term consequences with any drought because of nature and societys dependence on water.
Pdf definitions and effects of droughts researchgate. We use your linkedin profile and activity data to personalize ads and to show you more relevant ads. It can be a major weather event that affects animals, plants, and people. Today, the situation has thus become such that we will be soon facing the severe repercussions of our own actions in the past. If the drought is brief, it is known as a dry spell or partial drought. D0 abnormally dry, d1 moderate, d2 severe, d3 extreme, and d4 exceptional. Crop farmers describe drought as the absence of moisture, which inhibits crop growth. Drought monitor, established in 1999, is a weekly map of drought conditions that is produced jointly by the national oceanic and atmospheric administration, the u. This type of drought is defined by a lack of precipitation over a period of time. This report discusses why drought occurs in the united states.
A drought is a period of drierthannormal conditions that results in waterrelated problems. Drought impacts are a key indicator of vulnerability. An operational definition of drought helps people to identify the beginning, end, and degree of. Drought monitoring techniques and applications to freshwater management are summarized. While droughts can be defined as a climate phenomenon, their impacts on humans and the.
Causes, effects and control strategies 5 deforestation are maintained. Causes, effects and management mechanisms of drought crisis in. It often causes extensive damages to crops and natural ecosystems, creates water shortages, and increases risks of heat waves and wildfires. This is the type of drought that occurs when factors such as lack of rainfall, soil water deficits, and reduced groundwater levels combine to produce conditions that do not allow an adequate water supply for crops. Oct 21, 2009 we use your linkedin profile and activity data to personalize ads and to show you more relevant ads. Drought can be quantified and described in absolute terms such as the amount of soil moisture or lake levels or through relative measures for instance, pdsi in various forms, and these can be compared3,4. Lakes, rivers, and streams are the primary suppliers of downstream surface waters in various geographical regions around the globe. Problems associated with drought can have economic, environmental, and social impacts on both the areas where they occur and areas that have relations with those where the drought happens. Meteorological drought is defined usually comparing the precipitation of a precise place and moment to the average of precipitation of that place for a long period. The 201820 mozambique drought is an ongoing period of drought taking place in southern africa. A socioeconomic drought occurs when the demand for an economic good is greater than its supply due to a water deficit created by shortfalls in precipitation and other weatherrelated adverse changes.
Agricultural drought links various characteristics of meteorological or hydrological drought to agricultural impacts, focusing on precipitation shortages, differences between actual and potential evapotranspiration, soil water deficits, reduced groundwater or reservoir levels, and so forth. Zolotokrylin encyclopedia of life support systems eolss van nostrand reinhold company, new york. Droughts pdf download types of droughts and factors. The amount of precipitation at a particular location varies from year to year, but over a period of years, the average amount is fairly constant. It is rooted in various causes and there are also multiple ways to do away with it. Poverty is a multifacet phenomenon in todays globalised world. Drought causes serious environmental imbalances, which are summarized below. A drought or drouth is an event of prolonged shortages in the water supply, whether atmospheric belowaverage precipitation, surface water or ground water. East africa ea has been the primary focus for various drought studies in recent years.
In extremely hot seasons or because of certain human activities, these surface water flows may dry out downstream contributing to drought meaning the demands for water supply become higher than the available water. Lack or insufficient rainfall or precipitation this is the major cause of droughts in most regions. Types, causes and effects of droughts earth eclipse. A drought is a period of drierthannormal conditions that results in waterrelated. Drought and climate change union of concerned scientists. Drought has afflicted portions of north america for thousands of years. Severe, longlasting droughts may have been a factor in the disintegration of pueblo society in the southwest during the th century, and in the demise of central and lower mississippi valley societies in the 14. The time is not think about various reasons for drought, it is the time to take steps. Within the last decade, drought conditions have hit the southeastern us, the midwest. Vogt 1 executive summary of part i western cape province in south africa is going through a severe drought, affecting in particular the. This kind of drought takes a long time to become severe and equally long time to recover from it. National weather service august 2006 meteorological drought meteorological drought is usually defined.
However, a comprehensive analysis of droughts, including their evolution, complexity, social implications. Beyond direct economic impacts, drought can threaten drinking water supplies and ecosystems, and can even contribute to increased food prices. Low water availability creates shortages in water supplies that impact various activities and the environment. Hence, there is a pressing need for an overview of drought studies in ea. Drought results from belownormal precipitation often combined with warm temperatures over a period of months to years. Impacts of drought such as the effects on a regions climatology, increases in food insecurity and food prices and the integration of drought with factors such as the hivaids epidemic have led government to introduce various policies dealing, in particular, with drought risk. Drought is a period of time without substantial rainfall that persists from one year to the next. Droughts can be classified as meteorological, hydrologic, agricultural, and socioeconomic. The magnitude and causes of global drought changes in the. Department of agriculture, and the national drought mitigation center ndmc at the university of nebraskalincoln. Drought conditions are broadly grouped into five categories. The magnitude and causes of global drought changes. The drought began in late october 2018, and is negatively affecting food security in the region. Several famines have ravaged the country time and again and have claimed millions of deaths over the centuries.
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