10rsta.royalsocietypublishing.orgP h i l .T r a n s .R .S o c .A376:20160452 ........................................................
ensemble mean
IPSL-CM5A-LR  GFDL-ESM2M
0 1 02 03 04 05 06 07 0
% of days
HadGEM2-ES
IPSL-CM5A-MR MIROC-ESM-CHEM ACCESS1-0
Figure3. Simulatedchangesinthepercentageofdayswithdailytemperatureabovethe90thpercentilefor1981–2010at2 °C
globalwarming,forindividualHadGEM3simulationsdrivenbySSTsandSICsfromdifferentmembersoftheCMIP5ensemble,
andtheensemblemean.ThelabelsaboveeachpanelidentifythedrivingCMIP5model(orensemblemean).
Indices based upon daily precipitation often show more spatial variability in changes
than the temperature-based indices, and greater differences between ensemble members, but,
nevertheless, some consistent pictures still emerge.
The number of consecutive dry days is projected to increase over some regions and decrease
in others (ﬁgure 4). Southern Africa, the Mediterranean, Australia and northeast South America
are projected to have increased dry spell lengths, while this is projected to decrease in central and
eastern Asia. The general pattern of these projections is broadly consistent across the ensemble
members. However, the global mean changes vary in sign ( table 5 ), as a result of different
magnitudes of regional changes dominating in different ensemble members.
Perhaps more surprisingly, projected changes in maximum 5 day rainfall (Rx5day) also vary
in sign both geographically and between models ( ﬁgure 5). Extreme rainfall might simplistically
be expected to increase in a warmer climate, and indeed the global mean change is a consistent
increase in all ensemble members (table 5). Regional Rx5day is projected to increase over many
regions including parts of southeast Asia, southern South America, northern Australia and the
east coast of the USA. However, some regions (particularly, the central Amazon and the northern
coast of South America) are projected to see a decrease in Rx5day.
Large increases in Rx5day are simulated in south and southeast Asia in all models, but
with local details varying. Southeastern South America (broadly southern Brazil and northern
Argentina) also see large increases in Rx5day in all models. All models show only small changes
over central and north Africa, Europe and most of Asia. In northern South America, however,
some models show increases in Rx5day but others show decreases. This suggests that the
ensemble-mean result of a decrease in Rx5day in this area may be subject to large uncertainty.
Inter-model variations in the sign of changes are seen in a few other local localized regions.
The average length of ﬂood events (number of days in which the cumulative daily rainfall
excess is positive, compared to the 95th percentile of the baseline) generally increase over most
of the land surface, although this increase was mostly by a day or less ( ﬁgure 6). However, some