Intergenerational inequity from hydrological drought in a warming world

Area of Science:

• Climate Science
• Hydrology
• Environmental Science

Background:

• Warmer temperatures increase atmospheric moisture, intensifying hydrological droughts globally.
• Climate change exacerbates drought risk, creating intergenerational inequity for younger populations.

Purpose of the Study:

• To quantify and compare lifetime exposure to hydrological drought across different generations.
• To project future drought evolution and assess its impact on various age groups.

Main Methods:

• Utilized a cascade model chain with hybrid terrestrial models and 5 Global Climate Model (GCM) outputs under SSP5-85.
• Employed five hydrological models and a deep learning model to simulate drought evolution in 4091 river basins.
• Quantified lifetime drought exposure for age groups born in 1960 and 2020.

Main Results:

• Drought severity and duration are projected to significantly increase in Eastern America, Southern Brazil, and Western Europe (over 79% of basins).
• Extreme droughts exceeding historical records are anticipated, particularly impacting Western Europe.
• Individuals born in 2020 face a 12% greater exposure to hydrological drought hazards by the late 21st century compared to those born in 1960.

Conclusions:

• Future drought conditions under extreme warming pose a substantial threat to the well-being of younger generations.
• The study reveals a notable disequilibrium in drought exposure across age groups, with newborns facing significantly higher risks.
• Findings underscore the accelerating impact of climate change and the urgent need to address intergenerational climate justice.