Supplementary material to "The potential value of seasonal forecasts in a changing climate"

Abstract

S1. Effect of climate change on dry spell and heat stress frequency 12The effect of climate change on dry spell and heat stress frequency has been computed 13 for a number of thresholds (dry spells of 3, 5 and 10 days, days with THI values of 72, 78 14 and 84). The main sections show only the dry spells of 5 days and days with THI of 78. 15In this supplementary material section we also show the results for the remainder of dry 16 spell and THI thresholds. Figure S1 until Figure S4 show these results for the dry spells, 17 Figure S5 until Figure S8 show the results for the THI conditions. The results clearly 18 support that also for other thresholds than the ones presented in the main sections, the 19 same conclusions can be drawn: dry spell frequencies are not clearly increasing in a 20 changing climate, the current variability in dry spell frequency is much larger than its 21 expected change. The frequency of heat stress conditions clearly increases. It can further 22 be noted that extreme stress conditions with THI values above 84 are extremely rare in 23 the current climate, but towards 2100 such conditions will occur quite frequently across 24 low-lying areas such as the Zambezi delta and the Kalahari Desert (i.e. yellow coloured 25 areas in the right-hand panes of Figure S6