Global assessment of terrestrial water cycle resilience

Romi Lotcheris, Nielja Knecht, Lan Wang-Erlandsson, Juan Carlos Rocha 

Green water - transpiration, soil moisture, and land precipitation - is critical for Earth system stability and ecosystem productivity. Despite evidence of considerable and widespread change globally, its resilience, or ability to absorb and recover from disturbances, is not yet well understood. Here, we assess green water resilience using early warning signals (EWS) applied to global satellite time series of green water variables, and empirically evaluate these estimates against past abrupt changes. We find that a wider portfolio of context-appropriate EWS are needed to capture heterogeneous water–vegetation dynamics across eco-hydrological systems, and show that EWS provide limited but non-negligible additional skill in anticipating abrupt transitions when combined with environmental context. We find ecosystem-dependent signatures of resilience loss globally, with drylands and grasslands showing widespread critical slowing down, and high-latitude systems showing critical speeding up and flickering behaviour, highlighting emerging risks to green water dynamics under ongoing anthropogenic pressures.