Extended Data Fig. 8: Changes in the impact of warm droughts (SPEI) on negative GPP extremes over the northern midlatitudes between the 2000–2016 and 1982–1998 study periods.
From: Increasing impact of warm droughts on northern ecosystem productivity over recent decades
The change in negative GPP extremes was calculated as the difference in cumulative GPP anomalies linked to negative GPP extremes attributed to warm droughts (SPEI) per study period (2000–2016 minus 1982–1998; ΔGPP). a–c, Monthly anomalies in negative GPP extremes attributed to SPEI relative to the climatological mean of the first period for LUE (a), FLUXCOM (b) and TRENDY (c). Spirals start with the first entry of the time series (Jan. 1982; centre) and end in December 2016 (outside) with the year 1999 masked (grey; see Methods). Outside numbers indicate cumulative monthly GPP anomalies linked to negative GPP extremes over the two study periods 2000–2016 (first entry) and 1982–1998 (second entry). Thereby, brackets denote corresponding insignificant differences between these two periods (Mann–Whitney U-test, p-value < 0.05). d, Summarized relative changes (%) for the boreal growing season (April–September) in warm drought-driven GPP extremes, derived from panels a–c for each dataset.
