India among global flash drought hotspots from 1980-2015: Study

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• A study identified rapid drought intensification across India , United States, Brazil, southern Africa, Spain, western Russia and Australia as well.

Flash Drought

• It is the rapid onset or intensification of drought and is set in motion by lower-than-normal rates of precipitation
  • Accompanied by abnormally high temperatures, winds, and radiation. 
  • Together, these changes in weather can rapidly alter the local climate.
• The highest frequency of flash drought occurrence was primarily found within the tropics and subtropics.
  • They include a large portion of Brazil, the Sahel, the Great Rift Valley and India.
  • With composite flash drought occurrence within the 36-year time period (1980-2015) of analysis.
  • Additional areas within the tropics that had lesser, but notable flash drought occurrences included 
    • central Mexico, the Indochinese Peninsula, and northern Australia.
  • In the mid-latitudes, local hotspots of flash drought occurrence (10-20 per cent) exist across 
    • the central United States, Iberian Peninsula, Asia Minor, southwestern Russia, and northeastern China.

Study published in the Journal Nature Communications

• Selected Regions:
  • Study regions are over global hotspots where flash drought occurred in more than 30 per cent of the study years (1980–2015). 
  • The study identified rapid drought intensification across the United States, Brazil, southern Africa, Spain, western Russia and Australia.
• Key drivers:
  • Rapid drought intensification occurs due to 
    • a critical lack of precipitation and 
    • increased evaporative demand.
• In India:
  • A majority of the flash drought events occurred during the monsoon season.
    • Especially across the central, northwest and northeast regions of the country.
  • These regions experience their peak frequency at the beginning of their respective monsoon seasons
    • Primarily between May and September from 1980-2015.

• In Sahel Region:
  • The flash drought likely occurred during May-June, and was associated with increasing climatological rainfall.
  • Especially if the onset of Inter-Tropical Convergence Zone (ITCZ) induced and monsoon rainfall was delayed or significantly decreased.
• In Amazon:
  • Flash drought occurs most often in the dry season (July-September). 
  • Mainly due to the combined effect of 
    • increased evaporative demand, 
    • limited rainfall and 
    • increased evapotranspiration resulting in rapid soil moisture depletion.

Impact on Agriculture

• Flash droughts can develop in only a few weeks, they create impacts that are difficult to prepare for and mitigate. 
  • Even when environmental conditions seem unfavourable for rapid drought development.
  • A persistent lack of rainfall coupled with hot weather can create flash drought development with its associated impacts.
• Areas under the Flash drought hotspots
  • the corn belt across the mid-western United States, 
  • barley production in the Iberian Peninsula,
  • the wheat belt in western Russia, 
  • wheat production in Asia Minor, 
  • rice-producing regions in India and the Indo-china Peninsula, 
  • maize production in northeastern China and 
  • sorghum production across the Sahel.
• Trends
  • About 10-15 percent of areas under cultivation of rice and maize were affected during the monsoon seasons in India between 1951 and 2018.
• Future Implications
  • The researchers said that the trend only applies to the 36 year period i.e between 1980–2015 and 
  • Do not indicate that these trends will extend into the future.

Way Forward and Conclusion

• Limiting Global Warming
  • By limiting global warming to well below 2 degrees C, the numbers and frequency of the projected flash droughts may go down.
• Early warning Systems
  • Operational meteorological forecasts will help manage irrigation water demands and avoid considerable losses in agriculture.

Source: DTE