Key Findings
- Worldwide soil moisture is in decline. Studies using satellite, reanalysis, and geophysical data show a consistent trend of soil drying since 2000. This loss of moisture is considered by many scientists to signal a permanent shift in the global water cycle if current warming trends continue[1][2].
- Not all regions are equally affected: Nearly half of the global land area exhibits significant drying trends, especially in the surface and root zone soil layers, though some regions experience wetting. Drying is more pronounced in:
- Parts of Europe and the Mediterranean
- Central Asia (including the Black Sea–Caspian Sea region)
- Siberia
- Western USA and the Canadian Prairies
- Large regions of South America
- Parts of southern and northern Africa
- Northwestern Australia[3]
- Soil moisture recovery is limited. Once soils dry out due to strong droughts or warming, subsequent wet years do not fully restore moisture levels, due to increased atmospheric evaporative demand driven by higher temperatures[1].
Drivers of Global Soil Drying
- Increased Evaporative Demand: As the atmosphere warms, its ability to extract moisture from soils increases, creating a “thirstier” environment. This boosts water loss from soils, exacerbating drying even in the presence of average precipitation[1][2].
- Shifting Rainfall Patterns: Changes in precipitation, with some areas experiencing prolonged drought and others more intense (but shorter) rainfall, limit the soil’s ability to retain moisture effectively over time[1][3].
- Extreme Climate Events: Episodes such as El Niño have caused notable, abrupt drops in global soil moisture, especially in the early 2000s and mid-2010s, with little subsequent recovery[1].
Quantitative Overview (2000–2022)
Indicator | Surface Soils | Root Zone Soils | Citation |
Land area with drying trend | 49.3% | 44.5% | [3] |
Land area with wetting trend | 21.1% | 20.6% | [3] |
Areas with no trend consensus | 29.6% | 35.0% | [3] |
Regional Examples
- Europe & Mediterranean: Persistent drying, increasing drought risk.
- Central Asia & Siberia: Widespread soil moisture loss.
- Western USA, Canada, South America: Frequent and severe drying trends noted.
- Africa & Australia: Northern/southern regions are significantly affected; eastern and central Africa, plus northwest Australia, display marked drying.
Implications
- Agriculture & Water Supply: Drying soils lead to more frequent and severe droughts, reducing crop yields, stressing ecosystems, and threatening water resources for both agriculture and human consumption[1][3].
- Irreversibility: The intensity and persistence of current soil drying patterns suggest that returning to previous moisture levels may not be possible under ongoing climate trends, barring a significant change in global warming[1][2].
Scientific Confidence and Limitations
- Overall, reanalysis and remote sensing products confirm major drying trends. Some datasets do show wetting, particularly in areas receiving increased rainfall, but the dominant global pattern is drying, especially in key agricultural and ecological regions[3].
- Differences in climate models and data products contribute to uncertainty in the precise extent and speed of soil drying, but agreement is strong regarding the overall trend[3][1].
In summary:
Global soil drying is underway and is likely to intensify with continued warming, altering the hydrological cycle, ecosystems, and agricultural productivity on a worldwide scale[1][3][2].
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- https://www.carbonbrief.org/global-soil-moisture-in-permanent-decline-due-to-climate-change/
- https://insideclimatenews.org/news/27032025/earth-land-masses-drying-out-fast/
- https://hess.copernicus.org/articles/29/397/2025/
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