Climate Models Project More Intense Global Droughts Amid Rising Emissions

Key Findings from Latest Climate Models

New research using the latest generation of climate models (CMIP6) projects significant intensification of droughts in critical agricultural and ecological regions by 2100. Led by Dr. Anna Ukkola of the ARC Centre of Excellence for Climate Extremes, the study highlights how greenhouse gas emissions directly influence drought severity, with high-emission scenarios triggering irreversible impacts on water security and ecosystems.

Global Hotspots for Drought Intensification

Australia:
- Southwestern and southern Australia face prolonged droughts due to declining rainfall and higher evaporation rates. The Millennium Drought (1997–2009) serves as a benchmark for future conditions, with models indicating similar events could become 40% more frequent by 2050 under SSP5-8.5 (high emissions).
- Eastern Australia’s 2017–2020 drought, one of the worst on record, is now understood to involve complex land-atmosphere feedbacks, where reduced soil moisture amplifies heatwaves and rainfall deficits.
Amazon, Mediterranean, and Southern Africa:
- These regions are projected to experience droughts lasting 2–3 times longer than historical averages, with the driest months of the past becoming the new normal. For example, the Amazon’s SPI6 (Standardized Precipitation Index over six months) could drop by 30% by 2100, severely impacting rainforest resilience.
Paradox in Wetter Regions:
- Central Europe and boreal forests may see increased rainfall, but drought intensity during dry spells will rise due to higher variability. Even in these regions, the worst droughts could be 50% more severe than today.

Advances in Climate Modeling

The CMIP6 models, which inform the IPCC’s Sixth Assessment Report, provide unprecedented clarity by integrating both rainfall averages and variability:

Drought Duration: Tightly linked to long-term rainfall declines (e.g., Mediterranean and Central America).
Drought Intensity: Driven by rising rainfall variability, which exacerbates short-term water shortages.

A 2025 Nature dataset ([source 9]) using downscaled CMIP6 projections confirms these trends across four emissions scenarios (SSP1-2.6 to SSP5-8.5). For instance, under SSP5-8.5, the Mediterranean’s annual drought frequency could double, while drought months in southern Africa may triple.

Why Earlier Models Underestimated Droughts

Previous studies focused solely on rainfall averages, missing critical feedback mechanisms:

Evapotranspiration Dominance: In arid regions like Australia, rising temperatures increase evaporation, reducing soil moisture independent of rainfall changes ([source 1]).
Vegetation Feedbacks: Dryland vegetation, initially resilient to rainfall shifts, reaches tipping points where water stress triggers abrupt ecosystem collapse ([source 6]).

Dr. Ukkola’s DECRA project leverages these insights to improve seasonal drought forecasts, emphasizing soil-vegetation interactions often oversimplified in older models.

Implications for Agriculture and Policy

Agricultural Risks:
- Drought intensity-measured by the SPEI6 (incorporating evaporation)-is projected to rise 20–40% in global breadbaskets like the U.S. Midwest and India’s Indo-Gangetic Plain.
- A 2025 analysis of CMIP6 data warns that 20% of global harvest regions will face “extreme drought conditions” by 2100 if emissions remain unchecked ([source 1]).
Mitigation Matters:
- Mid-range emissions (SSP2-4.5) could halve drought intensification compared to SSP5-8.5. For example, southwestern Australia’s drought duration under SSP2-4.5 is projected to increase by 25% versus 60% under SSP5-8.5.

The Path Forward

“The latest models leave no doubt: reducing emissions now is the only way to curb drought extremes,” says Dr. Ukkola. Her team’s work with the ARC Centre’s ACCESS model aims to refine regional predictions, helping farmers and policymakers prepare for drier futures.

For stakeholders, tools like the Global Future Drought Layers dataset ([source 9]) offer granular projections to guide water management and crop adaptation. Yet, as Dr. Ukkola cautions, “No region-wet or dry-is immune to escalating drought impacts.”

Sources:

ARC Centre of Excellence for Climate Extremes (CLEx)
Geophysical Research Letters (2020, 2025)
Nature Scientific Data (2025)
CMIP6 Model Ensemble Analysis

This article integrates updated climate projections and datasets to inform adaptive strategies in agriculture, ecology, and water resource management.