Kashyap et al. (2026) Increased moisture stress and weakened resilience to aridity limit global greening

Identification

• Journal: The Science of The Total Environment
• Year: 2026
• Date: 2026-01-23
• Authors: Rahul Kashyap, J. Kuttippurath
• DOI: 10.1016/j.scitotenv.2026.181416

Research Groups

• CORAL, Indian Institute of Technology Kharagpur

Short Summary

This study investigates the response of global photosynthesis to moisture stress in current (2000–2021) and future (until 2100) climates, finding that increased moisture stress and weakened resilience to aridity limit global greening, particularly in vulnerable ecosystems.

Objective

• To investigate the response of global photosynthesis to moisture stress (higher demand and lower availability of moisture) in current (2000–2021) and future climate scenarios (until 2100).

Study Configuration

• Spatial Scale: Global, biomes, land covers
• Temporal Scale: Current (2000–2021), future (until 2100), recent decade (2010–2019), previous decade (2000–2009)

Methodology and Data

• Models used: Statistical techniques, machine learning (ML) techniques, Random Forest (RF)
• Data sources: Satellite remote sensing (Fraction of Photosynthetically Active Radiation (FPAR), Enhanced Vegetation Index (EVI), Solar-Induced Fluorescence (SIF)), reanalyses, climate projection data

Main Results

• Vapour Pressure Deficit (VPD, 39.8%) exerts greater control on global photosynthesis than Soil Moisture (SM, 31.4%) and Climatic Water Deficit (CWD, 28.8%).
• VPD exhibits a direct causal relationship with photosynthesis across biomes and land cover types, while SM and CWD influence photosynthesis through VPD in the absence of direct causality.
• Enhanced land (CWD, 16.7%) and atmospheric (VPD, 4.3%) evaporative demands led to a reduction in SM (−2.2%) in the 2010–2019 decade compared to 2000–2009.
• Global photosynthesis shows enhanced cumulative growth rates (CGR), yet a slowdown or reversal of global greening (−2.8% CGR) is observed, notably in grasses and tropical biomes due to rising moisture stress.
• Cropland, and temperate and arid biomes exhibit high sensitivity and low resilience to dryness stress.
• Global photosynthesis gained resilience against land evaporative (CWD, 6.7%) and atmospheric aridity (VPD, 4.1%) but lost resilience against SM drying (−0.5%) from 2000–2009 to 2010–2019.
• In moisture-stressed ecosystems, a gain in resilience facilitates photosynthesis, while a decline in resilience results in a slowdown or reversal of greening.
• Projections for the 21st century indicate sparse canopy greening and dense canopy browning driven by moisture.

Contributions

• Quantifies the relative influence of VPD, SM, and CWD on global photosynthesis across different biomes and land covers.
• Identifies direct and indirect causal pathways of moisture variables on photosynthesis.
• Assesses the resilience of global photosynthesis to various moisture stress factors over recent decades.
• Provides insights into the mechanisms driving the slowdown or reversal of global greening in moisture-stressed ecosystems.
• Projects future trends of canopy greening and browning under changing moisture conditions.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Kashyap2026Increased,
  author = {Kashyap, Rahul and Kuttippurath, J.},
  title = {Increased moisture stress and weakened resilience to aridity limit global greening},
  journal = {The Science of The Total Environment},
  year = {2026},
  doi = {10.1016/j.scitotenv.2026.181416},
  url = {https://doi.org/10.1016/j.scitotenv.2026.181416}
}