Fig. 6: Warming triple-threat accelerates mortality risks.
From: Global field observations of tree die-off reveal hotter-drought fingerprint for Earth’s forests
Under two warming scenarios, leading indicators of tree mortality representing the triple-threat that warming poses to tree survival at the plots in our analysis departed from recent values toward drier (PDSI (a), VPD (c)) and warmer (TMAX values, b) indicating further warming will shift climatic space toward that recently associated with mortality events. In a–c, the density distributions of PDSI, TMAX, and VPD during observed (+0.7 °C, light blue) and warmed +2 °C (pink) and +4 °C (red) climate scenarios are shown. In d, open circles show the mean (n = 675 sites) frequency of mortality year hotter-drought fingerprint conditions (when for a particular location, all 6 monthly variables met or exceeded the local hotter-drought fingerprint conditions of the mortality year), while the x-axis represents the mean warming since pre-industrial (1850–1879) climate. Error bars represent 95% confidence interval and the dashed gray line is an exponential fit.
