Compound indicators for vulnerable ecosystems (CIVE v1.0) framework

Terrestrial ecosystem risk is shaped by compound extremes that monthly indices can miss. We introduce the Compound Indicators for Vulnerable Ecosystems (CIVE), an 8-day, 0.125-degree framework separating hazard exposure from ecosystem vulnerability across the conterminous United States during 2000–2024. Fixed NLDAS-2 thresholds define a five-hazard catalogue. A target-year-excluded Dynamic-local reference built from up to ten nearest eligible non-hazard years defines expected GOSIF GPP. Exposure combines normalized event frequency and duration; vulnerability integrates impact magnitude, response time, recovery time, and relative resilience; risk is their geometric mean on joint support. GOSIF tracks 8-day AmeriFlux GPP ( r = 0.83, n = 8924), and event-scale losses agree between tower and grid estimates ( r = 0.78, n = 12). Across 25 annual records, national EI, VI, and RI average 0.023, 0.086, and 0.037. Their Sen slopes are +0.0024, −0.0018, and − 0.0002 decade −1 (Hamed–Rao p = 0.306, 0.870, and 0.981), providing no evidence of national trends. Sixteen overlapping 10-year windows show a modest positive EI direction and negative VI and RI directions, but these diagnostics are not independent because adjacent windows share nine years. Spatial contrasts persist: heatwave vulnerability and risk center on the Southwest and Southern Great Plains, flash-drought impacts extend through the Plains and upper Midwest, and cold-wave vulnerability is restricted to winter-active warm margins. Fixed-reference and alternative-window analyses show that temporal direction depends on method. CIVE supports hazard-specific spatial diagnosis, while national VI and RI trends remain unresolved.