Megadrought, megapluvial conditions will become the new normal under high emissions scenario: Report

According to a new report, extreme drought or extreme rainfall (pluvial) conditions will become the norm for the rest of the 21st century for some parts of Earth.

Key Findings:

• Western Europe, southwestern United States and northern Mexico, southern Africa and the western Amazon will see the earliest emergence of megadrought conditions.
• Emergence of megapluvials “affects less of the global land surface”, but does take place in India and eastern Africa.
• ‘Hot droughts’ can increase in frequency. A long-term drying trend does not preclude the occurrence of an unusually wet interval and vice versa.
• Soil moisture changes will be so large in some regions that conditions that will be termed a ‘megadrought’ or ‘megapluvial’ event.
• In some regions, including Europe and western North America, this shift may have already taken place and could be in the offing elsewhere.
• Emergence of drought and pluvial conditions will occur over 61 per cent of the global land surface (excluding Antarctica) by 2080.

Need to adapt and manage:

• There is an increasingly urgent need to understand the full range of natural climatic variability, especially on decadal and longer timescales.
• Since many regions have or will soon make the transition to a hydroclimatology defined by megadrought / pluvial conditions, water management needs to shift accordingly.
• Over a fifth of India’s land area is facing drought-like conditions. Uneven distribution and failed monsoon are among the main causes.

Megadrought:

• A megadrought is a period of extreme dryness that lasts for decades.
• Within that period there may be occasional better, wet, years, but the respite is brief.
• The dryness soon returns and drought maintains its long-term grip.
• It is a period of 20 to 30 years where conditions are drier than average.
• There may be some wet years sprinkled in, but drought impacts remain throughout the period. These are much longer in scale than droughts, which typically last months or years