Drought is a phenomenon with a slow onset and various definitions. Its impacts can vary depending on its characteristics and the demand for water for different uses. We invite you to read more about this topic.
What is Drought?
Drought is the decrease in available water over a specific period and in a particular area. Accordingly, drought can be described as a sporadic phenomenon that can also affect non-arid regions. In fact, drought is a recurring feature of the hydrological cycle and can occur in both dry and humid regions.
Drought is a term that indicates a condition of permanent lack of water resources characteristic of the climate of a given place ; it is a temporary and relative condition, defined as a deviation from average (climatic) conditions.
Features
Droughts occur when there is abnormally low rainfall over a prolonged period of time. This means that a desert would not be considered to be in drought unless it had less rain than normal for a long period of time. Droughts can last from weeks to months and even years.
Drought is characterized by intensity, duration, area and frequency, the impact of drought on vegetation depends on various factors such as intensity and duration. At the same time, rain vegetation has a higher sensitivity and response to drought than vegetation.
Intensity: The deviation from the average level of drought depends on its type (agricultural, hydrological, etc.), the degree and duration of temperature and humidity , also on land use and to a lesser extent, the affected area; regions that, on average, have more rainfall are characterized by a greater intensity of drought compared to regions that receive less rainfall.
The duration of a drought: This is the period of time from its beginning to its end. In areas with a higher frequency of drought, its duration is usually shorter, and vice versa; recovery from droughts with longer durations is slower compared to those with shorter durations.
Area: Due to the fact that drought can cover a huge territory for a long time, its area is an important feature.
Repeatability: At higher elevations, precipitation is greater and high temperatures are less common than in flat terrain. As a result, droughts are less intense at higher elevations, and their frequency is much lower in areas with large bodies of water.
Causes
A drought is caused by drier than normal conditions which can eventually lead to water supply problems, really high temperatures can make a drought worse by causing moisture to evaporate from the soil, the fact that a region is hot and dry it does not necessarily mean that you are experiencing a drought.
Rain and snow do not fall evenly on Earth. Some regions are routinely wet and others are routinely dry, from season to season and from year to year, the amount of rain or snow in one place can vary.
However, over a period of many years, the average amount of precipitation in a region is fairly consistent. When a particular area receives less rain than normal, the soil also receives much less moisture, the soil begins to dry out, and plants die.
When this pattern continues for several weeks, months, or years, the flow of streams and rivers decreases, and water levels in lakes, reservoirs, and wells drop. Eventually, the unusually dry weather causes water supply problems, and the dry period becomes a drought.
Consequences
Drought could be one of the most serious consequences of climate change from a human and economic perspective. On a global scale, droughts are likely to lead to losses in agricultural income on the scale of billions of dollars and worse, will force the migration of millions of people in arid regions of the world.
Drought has plagued civilization for millennia, and humans have learned to adapt to areas where water supplies are neither abundant nor regular. However, the critical difference today is the explosive population growth, which is placing far greater pressure on water supplies.
Combined with projections that parts of the world will become significantly drier in coming decades, drought is likely to be a much more serious problem in the future than it was in the past.
Types of Droughts
There are some indicators that experts use to determine if a condition can be called a drought, these indicators help local authorities, states or governments plan and release appropriate relief resources for affected areas. In addition to those, here are some common drought scenarios:
Meteorological drought
This type is usually determined by the general lack of moisture in the climate, such as lack of precipitation, and the play of other weather conditions such as dry winds, high temperatures, etc. It is expressed relative to the "average" conditions of the region over a long period of time.
It is usually an indicator of a possible water crisis if the condition is prolonged, the meteorological drought can begin and end immediately. Basically, that means that the definition of a drought in a rain forest is very different from the definition of one in a more arid climate like a desert.
Agricultural drought
This is when atmospheric moisture is reduced to the extent that soil moisture is affected. Here crops and animals are affected and evapotranspiration is also affected.
For example, if it has been particularly dry when a crop is planted, that could affect the rate at which those plants reach maturity and that can negatively affect crop yield.
On the other hand, if there is a lot of moisture at the initial planting, but not enough later in the growth cycle, that crop still has a fighting chance. Therefore, there may be a water shortage later in a crop's life cycle without that shortage qualifying as a drought.
The number of agricultural droughts is also increasing thanks to good weather change, as the earth warms, snow melts earlier in the year and in some cases precipitation that would have been snow never makes it as far and falls instead as rain.
Hydrological drought
This occurs when there is a deficiency in the surface and groundwater supply in a region, often as a result of decreased precipitation, over-reliance on surface water for agriculture, energy, and other needs.
Hydrological drought does not usually occur at the same time as meteorological drought, in a way, this decrease in the quantity and quality of surface and groundwater is the effect of meteorological drought.
The Climate and Energy Solutions Center explains that this is a positive feedback loop "where dry soils and diminished vegetation cover can further suppress rainfall in an already dry area."
socioeconomic drought
This condition is when some supply of some goods and services, such as energy, food and drinking water, is reduced or threatened by changes in meteorological and hydrological conditions.
Sometimes growing populations and excessive demands for such goods worsen to the point of creating stress on what little water is available, it takes a long time for this type of drought to kick in and a long time to recover from it.
Socioeconomic drought is often the culprit behind rising food prices when drought has limited the supply of a product and the supply far exceeds the cost; in short, when water scarcity leads to a shortage of crops or other products, that is a socioeconomic drought.
Drought as a global phenomenon
Drought is a prolonged dry period in the natural climate that can occur anywhere in the world, it is a slow on-set phenomenon caused by lack of rain and compound actors, such as poverty and inappropriate land use, increase the vulnerability to drought.
When drought causes water and food shortages, there can be many health impacts on the population, which can increase morbidity and lead to death. In recent years, most of the mortality has been related to drought.
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It is difficult to impartially measure the characteristics of droughts in processes such as their strength, magnitude, permanence and extension, until now, the equanimity in the definition of drought has greatly hindered the establishment of a unique and global drought index.
El Niño, is a climatic phenomenon that causes excessive heat and a decrease in rainfall in addition to food shortages, generally occurs at intervals of two to seven years and can last up to 18 months, this phenomenon has wide implications on the climate and global climate regimes; in some regions it can cause a decrease in rainfall and the appearance of droughts.
Drought affected regions
The two largest deserts on the planet dominate the coldest places on earth, the Arctic and the Antarctic, the Sahara desert remains the largest hot desert in the world, global warming is accelerating desertification and by 2050 a large some of the land would have limited access to fresh water.
Morocco
The southern part of the country experiences rainfall between 100 mm and 200 mm in a year. Although the country is prone to drought, it is the fifth largest economy in Africa, the government has established a contingency plan to mitigate the effects of recurrent droughts.
Uganda
The Congo rainforest covers eastern Uganda, but the northern part bordering South Sudan is vulnerable to Saharan encroachment. The area experiences persistent drought , leaving half a million people with very little food and water. Despite years of government intervention, the situation in northern Uganda remains critical.
Somalia
Unfortunately, food security is a widespread concern in Somalia. One reality affecting this is the fact that only 1.75% of Somalia is arable land.
Iran
73% of the country is considered desert land, leaving 27% as agricultural land, about 6,5% of the land is forested, while a percentage of 1,1% is considered permanent cropland.
Pakistan
The Thar desert in the southern part of the country has been abandoned as thousands of people and millions of livestock migrate in search of humane conditions. It is anticipated that by 2025 Pakistan will face absolute water scarcity as the country's largest supplier of fresh water; the Indus River basin continues to dry up.
China
In recent times, China's north and southwestern regions have been facing a persistent drought that leaves millions of people on the brink of starvation. About three million people in northern China's Shanxi province are in urgent need of water, while a third of the area's wheat crop dries up due to lack of irrigation or rainwater.
Afghanistan
Afghanistan is among the driest and most arid countries in the world. Around 2.5 million people have been affected and need help from the government and international aid, the southern parts of the country lose around 60-80% of animals every time a drought occurs.
Sudan
Around 2,8 million people in Sudan are affected by drought each year. Severe effects are being felt in southern Sudan, where a drought is sweeping across the country. Sudan is largely a desert and the country, like Egypt, relies on the Nile River for water.
Ethiopia
Crop failures due to drought and recurring insecurity in some regions of Ethiopia have led to food instability and falling food stocks across the country. Approximately one million people, including children under the age of five, require government and international intervention each year.
Protection and mitigation
Drought is a natural hazard, slow onset and evolving over months or even years, can affect a large region and cause little structural damage, drought impacts can be reduced through preparedness and mitigation.
The response includes better drought monitoring , improved water and crop management, increased groundwater supplies, greater public awareness and education, watershed intensification and local planning, reduced water demand, and water conservation.
Water supply projects can also be implemented to mitigate drought, with a view to strengthening drought preparedness.
As part of a drought mitigation plan, activities such as water use planning, rainwater harvesting, using surface and underground structures, improved management of canals and wells, exploration of additional water resources through drilling and dam construction.
Farmers can prepare for drought by developing plans that cover all aspects of farm management and take into account variable climate types.