The Environmental Effects Of Drought Environmental Sciences Essay

Drought is a normal part of climatic conditions; extreme climatic events, often described as a natural hazard (Dept. of Agriculture and cooperation, 2009). Drought has long been recognized as one of the most dangerous causes of human misery. It has today the unfortunate distinction of being the natural disaster that annually claims the most victims. Its ability to cause widespread misery is actually increasing day by day.

Drought differs from other natural disasters in its slowness of onset and its commonly lengthy duration. The severity of the drought depends upon its duration, the degree of moisture deficiency, and the size of the affected area. Drought is a hazard that requires many months to emerge and that may persist for many months or years thereafter. This type of hazard is known as a “creeping hazard” (Coppola, 2007).

It is difficult to provide a precise and universally accepted definition of drought due to its varying characteristics, impacts, across the different regions of the world, such as rainfall pattern, human response and resilience and diverse academic perspectives (Dept. of Agriculture and cooperation, 2009). In general, drought is an insidious natural hazard that results from a departure of precipitation from expected or normal that, when extended over a season or longer period of time, is insufficient to meet the demands of human, plant and animal activities ( A Primer for parliamentarians, NDMD).

In the literature, drought has been classified into four categories in terms of impact:

Meteorological Drought

Meteorological drought is defined as the deficiency of precipitation from expected or normal levels over an extended period of time. Meteorological drought usually precedes other kinds of drought. Meteorological drought is said to occur when the seasonal rainfall received over an area is less than 25% of its long term average value. It’s further classified as a moderate drought if the rainfall deficit is 26-50% and severe drought when the deficit exceeds 50% of the normal. The following examples of “meteorologic droughts” from different countries at different times show why it is a poor idea to apply a definition of drought developed in one part of the world to another:

United States (1942): less than one tenth inch of rainfall in 48 hours

Great Britain (1936): fifteen consecutive days with daily precipitation totals of less than one hundredth of an inch

Libya (1964): when annual rainfall is less than 7 inches

India (1960): actual seasonal rainfall is deficient by more than twice the mean deviation

Bali (1964): a period of six days without rain. (Institute of Food and Agricultural Sciences, 1998)

Under any circumstances, meteorological measurements are the first indicators of drought.

Agricultural Drought

Agricultural drought, usually triggered by meteorological and hydrological droughts, occurs when soil moisture and rainfall are inadequate during the crop growing season causing extreme crop stress and wilting. Plant water demand depends on prevailing weather conditions, biological characteristics of the specific plant, its stage of growth and the physical and biological properties of the soil. Agriculture is usually the first economic sector to be affected by drought (Institute of Food and Agricultural Sciences, 1998).

Hydrological Drought

Hydrological drought refers to deficiencies in surface and subsurface water supplies. It is measured as stream flow, and as lake, reservoir and ground water levels. There is a time lag between lack of rain and less water in streams, rivers, lakes and reservoirs, so hydrological measurements are not the earliest indicators of drought. When precipitation is reduced or deficient over an extended period of time, this shortage will be reflected in declining surface and subsurface water levels (Institute of Food and Agricultural Sciences, 1998).

Socioeconomic Drought

Socioeconomic drought is what happens when physical water shortage starts to affect people, individually and collectively. Or, in more abstract terms, most socioeconomic definitions of drought associate it with the supply and demand of an economic good (Institute of Food and Agricultural Sciences, 1998).

Drought in India

Drought gas a serious problem for India, and it has affected many part of the country intermittently. Certain regions of the country identified to be drought-prone. Increased climate variability has made rainfall pattern more inconsistent and unpredictable in the country increasing the recurrence of drought or drought like situation. A deficiency of rainfall causes depletion of both surface and ground water levels and adversely affects agricultural operations.

In India, around 68% of the country is prone to drought in varying degrees. Of the entire area, 35% of the area, which receives rainfall between 750 mm and 1,125 mm, is considered drought-prone, while another 33%, which receives less than 750 mm of rainfall, is called chronically drought-prone. A further classification of India’s regions into arid (19.6%), semi-arid (37%), and sub-humid areas (21%) has been dealing with geographical spread of drought (Dept. of Agriculture and cooperation, 2009).

In India, the occurrence and conditions of drought are influenced by a number of factors. Rainfall and cropping patterns are different across many geographical regions. It is not just the deficiency of the rainfall, but also the uneven distribution of rainfall across the season, duration of rainfall deficiency and its impact on different regions of the country that characterize drought conditions. Even though India receives abundant rain as a whole, disparity in its distribution over different parts of the country is so great that some parts suffer from perennial dryness. In other parts, however the rainfall is so excessive that only a small fraction can be utilized. Around 33% of the cropped area in the country receives less than 750 mm rain annually making such areas as hotspots of drought.

Impacts of Drought

Drought produces wide ranging impacts that span many sectors of the country. Drought has both direct and indirect impacts. One of the sectors where the direct impact of drought felt is agriculture. With the increased intensity or extended duration of drought prevalence, a significant fall in food production is noticed. The drought not only affects the food production at the farm level but also the national economy and the overall food security as well. Other direct impacts includes: depleted water levels, deficit in ground water recharge, land degradation, and damage to wildlife and fish habits. When direct impacts have multiplier effects through the economy and society, they are referred to as indirect impacts. These include a reduction in agricultural production that may result in reduced income for farmers and agribusiness, increased prices for food and timber, unemployment, reduced purchasing capacity and demand for consumption, default on agricultural loans, rural unrest, and reduction in agricultural employment leading to migration and drought relief programmes.

The impacts of drought are classified as economic, environmental, and social.

Economic Impacts

Economic impacts refer to production losses in agriculture and related sectors, especially forestry and fisheries, because these sectors rely on surface and subsurface water supplies. It causes a loss of income and purchasing power, particularly among farmers and rural population dependent on agriculture. All industries dependent upon the primary sector for their raw materials would suffer losses due to reduced supply or increased prices. Drought thus has a multiplier effect throughout the economy, which has a dampening impact on employment, flow of credit and tax collections. If the drought is countrywide, macroeconomic indicators at the national level are adversely impacted. (Dept. of Agriculture and cooperation, 2009)

Environmental impacts

Environmental impacts, such as lower water levels in reservoirs, lakes and ponds as well as reduced flows from springs and streams would reduce the availability of feed and drinking water and adversely affect fish and wildlife habitat. It may also cause loss of forest cover, migration of wildlife and their greater mortality due to increased contact with agricultural producers as animals seek food from farms and producers are less tolerant of the intrusion. A prolonged drought may also result in increased stress among endangered species and cause loss of biodiversity.

Reduced stream flow and loss of wetlands may cause changes in the levels of salinity. Increased groundwater depletion, land subsidence, and reduced recharge may damage aquifers and adversely affect the quality of water (e.g., salt concentration, increased water temperature, acidity, dissolved oxygen, turbidity). The degradation of landscape quality, including increased soil erosion, may lead to a more permanent loss of biological productivity of the landscape (Dept. of Agriculture and cooperation, 2009).

Social impacts

Social impacts arise from lack of income causing out migration of the population from the drought-affected areas. People in India seek to cope with drought in several ways which affect their sense of well-being: they withdraw their children from schools, postpone daughters’ marriages, and sell their assets such as land or cattle. In addition to economic hardships, it causes a loss of social status and dignity, which people find hard to accept. Inadequate food intake may lead to malnutrition, and in some extreme cases, cause starvation. Access and use of scarce water resources generate situations of conflict, which could be socially very disruptive. Inequities in the distribution of drought impacts and relief may exacerbate these social tensions further. (Dept. of Agriculture and cooperation, 2009)

Drought in Kerala

Drought in Palakkad

The Palakkad district of Kerala State is the land of paddy fields and palmyrahs. It is considered as one of the ‘rice bowls’ of the State.