FLASH DROUGHTS – GEOGRAPHY
News: What a new study says on the link between ‘flash drought’ and climate change
What's in the news?
● As global warming continues, more abrupt dry spells could have grave consequences for people in humid regions whose livelihoods depend on rain-fed agriculture.
● A new study found that flash droughts occurred more often than slower ones in tropical places like India, Southeast Asia, sub-Saharan Africa and the Amazon basin.
Key takeaways:
● Flash droughts, the kind that arrive quickly and can lay waste to crops in a matter of weeks, are becoming more common and faster to develop around the world, and human-caused climate change is a major reason, a new study has found.
Flash Drought:
● Flash droughts occur very quickly due to the rapid depletion of soil moisture. It is different from normal drought conditions that develop in months, but the flash drought happens within a week or two.
India and Flash Drought:
● Over 68% of India’s land area is vulnerable to drought.
● NITI Aayog, under the Composite Water Management Index report, highlighted that about two lakh people die in India every year due to inadequate water and sanitation. It also states that 6% of GDP will be lost by 2050 due to the water crisis.
● A paper published in January 2021 predicted that by the end of the 21st century, the frequency of concurrent hot and dry extremes in India will rise by about five-fold. This can cause approximately a seven-fold increase in flash droughts.
Causes of Flash Drought:
1. Increased evapotranspiration:
● Lack of rainfall coupled with increased evapotranspiration makes flash drought unique from conventional drought development.
● Evapotranspiration is the combination of evaporation from the land surface and transpiration from vegetation.
● Both of these processes act to transfer water from the land surface to the atmosphere.
2. Global warming:
● The increased frequency and intensity of extreme weather events such as droughts, floods, heat/ cold waves, cyclones, delayed or early onset of rains, long dry spells, early withdrawal, during the last two decades has been attributed to global warming.
● Greenhouse emissions will significantly increase the frequency of extreme hot and dry periods, which are the main drivers of flash droughts.
3. Precipitation deficit:
● When precipitation deficit occurs over an extended period of time, soil moisture is depleted by evapotranspiration which desiccates land surface.
4. Failed Monsoon:
● For Example in 2018 >> South-West monsoon that provides 80% of India's rainfall, fell short by 9.4% which brings drought like situations in India
5. High precipitation variability:
● Tropics and Sub-tropics have high potential for drought development due to high precipitation variability and evaporative demand.
6. Oscillation of the Inter-Tropical Convergence Zone (ITCZ):
● Flash drought development is more likely to occur in the May-June (period associated with increasing rainfall) if onset of ITCZ-induced rainfall is delayed/reduced, in combination with increased evaporative demand.
7. Anticyclones:
● They have a dual impact on flash drought development such as
a. They suppress rainfall which limits soil moisture replenishment.
b. Less cloud coverage and high surface temperatures increase evaporative demand of moisture.
8. Over-exploitation:
● Overexploitation of groundwater and sub-optimum conservation of surface water leading to inadequate water availability for irrigation.
● Traditional water harvesting systems have been largely abandoned.
9. Unsustainable agricultural practices:
● Growing crops that do not suit the agro-climatology of a particular region.
● For example, cultivation of sugarcane in Vidarbha region of Maharashtra and Rice in Punjab region.
○ Rice and sugarcane are water-intensive crops and growing them in an area where less water is available made the area prone to agricultural drought.
● Excessive use of High Yielding Seeds (HYV) as these seeds requires more water and proper irrigation.
Impacts of Flash Drought:
1. Decreases production:
● 2020 study - about 10-15% areas under cultivation of rice and maize were affected by flash droughts during monsoon season in India between 1951- 2018.
● Flash droughts of 1979, 1976, and 1982 are the 3 most severe flash droughts that affected Kharif crops during the monsoon season in India.
2. Depletion of soil moisture:
● Flash drought development with enhanced evapotranspiration and a lack of rainfall can quickly deplete soil moisture and lead to devastating impacts on agriculture and ecosystems.
3. Impact on economy:
● Flash drought has a ‘multiplier effect’ on the economy.
● As per a report of the UN Office for Disaster Risk Reduction (UNDRR), the impact of severe droughts is estimated to be about 2-5% of India’s GDP per annum.
4. Increase farm distress:
● As per recent report, a temperature increase of a single degree Celsius in one day corresponded to about 67 suicides, on average.
● More than 12,000 farmers have committed suicide in Maharashtra between 2015-2018 mainly due to drought related distress.
5. Fiscal implications:
● The government is faced with increased expenditure on relief, social welfare, health and water supplies, consumption-related subsidies on food distribution, and the logistical costs of drought related imports.
● Increased budgetary pressures, resulting from lower revenues and higher expenditure, are usually met by either external and internal borrowings, higher taxes or the imposition of new taxes
6. Environmental impact:
● Low water levels in water bodies (lakes, ponds, reservoirs etc.) will reduce availability of drinking water and adversely affect flora and fauna.
● It causes deforestation, wildfires and increased desertification.
● Frequent flash droughts can increase stress on endangered species and cause loss of biodiversity.
7. Distress migration:
● People tend to migrate from drought prone areas to water surplus areas. This may create crowding in certain places, social tensions due to sudden demographic changes etc.
8. Malnutrition:
● Due to reduction in crop yield, food security is threatened as inadequate intake of food will cause malnutrition.
● According to the paper published in Nature Communications (2019), India is a hotspot for flash droughts and this could have major implications on the country’s crop production.
Need for Mitigation Measures:
1. Long-term irrigation management:
● A long-term strategy is required for managing water resources through irrigation projects in India.
● It consists of several measures which would expand the area under irrigation and reduce the incidence of drought.
2. Monitoring reservoirs:
● It is necessary for the State irrigation department to set up a monitoring system for water stored in reservoirs, exercise appropriate control on releases of water from these reservoirs and plan for judicious use of water resources.
3. Conjunctive use of surface and groundwater:
● This concept is very essential, especially in drought areas to increase the production per unit of water. It allows flexibility in cropping patterns and multi-cropping in the canal command.o
4. Increasing storages:
● Water storage capacity in the States could be increased through expeditious completion of irrigation projects.
5. Integrating small reservoirs with major reservoirs:
● As large dams are difficult to construct due to high costs and large-scale displacement of people, there is an increased emphasis on creating small reservoirs.
● It is, therefore, very important that minor schemes are integrated with the canal systems of major reservoirs.
6. Early prediction and warning:
● Early-warning systems (EWS) can identify trends in climate and sources of water that are required to detect the emergence or probability of the occurrence of flash droughts.
● For example, IMD monitors agricultural drought every two weeks on a real-time basis during kharif and rabi crop seasons.
7. Monitoring by states:
● State Governments should consider setting up of Drought Monitoring Centres (DMCs) staffed by a multi-disciplinary team of meteorologists, hydrologists and agriculture scientists to analyse information on drought parameters from National and State level agencies.
8. Use of satellites:
● Satellite imagery can be accessed by relevant agencies from ISRO to check for anomalies.
● For example, delayed sowing indicates rainfall deficiency and wilting of crops signifies soil moisture stress – both are indicators of flash drought.
9. Ensuring community participation:
● State Governments need to encourage the formation of water user’s associations (WUAs) for community based management of water delivery systems.
● Organize Community-based Consultations through Gram Sabha.
● Strengthening women’s Self-help Groups will increases resilience of the households in responding to drought.
10. Empower Panchayati raj institutions:
● Several drought relief and mitigation measures could be implemented through the PRIs more effectively.
● The necessary budget allocations and implementation support should be provided to these institutions for launching programmes in drought-affected areas.
● PRIs improve the delivery mechanism and reduce the impact of drought.
11. Inter-Agency cooperation:
● Multiple agencies are involved in monitoring various parameters for flash drought. Their efforts need to be synergized for efficient dissemination of information and activate contingency measures.
12. Linking climate change adaptation and disaster risk reduction:
● Adaptation to climate variability such as short-term cropping, inter-cropping, small-scale fodder cultivation, small-scale fish cultivation in mini-ponds must be integrated with drought management programmes.
13. Crop management practices:
● Cultivation of drought resistant crops and crop varieties followed by scientific management practices would lead to drought proofing over a period of time.
● The State departments should ensure adequate availability of drought resistant seeds and encourage farmers to adopt better crop management practices from time to time.
If not predicted and discovered early enough, changes in soil moisture that accompany flash drought can cause extensive damage to agriculture, economies, and ecosystem goods and services.