Fig. 5: Tracing local risks to develop an aggregate RFC summary.

a–c The number of people experiencing local risks equal to, or worse than, “moderate,” “high” or “very high” categories, at different thresholds of global temperature rise, and considering all dimensions of uncertainty explored in Fig. 4 and Figs. S1–S4. Darker markers show the outcomes for the median CMIP5 results, and using the moderate vulnerability category; the lighter colours show the full range of outcomes. The aggregate risks assignments in d are chosen using the darker circles in a–c, by selecting the highest risk category which is experienced by at least 0.75 (“risk-averse”), 1.5 (“risk-neutral”) or 3 billion (“risk-tolerant”) people for each GMT-SSP combination. e shows how the aggregate risk summary (or “burning ember” diagram) is calculated, with uncertainty ranges drawn from the range of plausible outcomes presented in d. Regional perspectives downscaling of global risks are presented in f. Thresholds for population exposed have been rescaled to the national level relative to the SSP2 2050 population (globally 9.2 billion). Country-level exposure thresholds are set to 16% of the country’s SSP2 2050 population. Country-level risk is shown here for “risk-neutral” thresholds under SSP2 and with a “moderate” vulnerability assumption. g A sensitivity assessment of risks starting from a regional perspective for the USA assuming regional “high risks” to be reached at 1.5 °C. The configuration where this is the case is based on a pessimistic vulnerability assumption and aggregation threshold set at 5.5% of population, and risks for other countries and the global level in g are assessed using the same methodology.