Climate change impacts and vulnerability in Europe 2016

(b)
42
0.0
Figure 3.10 Projected changes in northern hemisphere September sea ice extent
32
Changes in the climate system
−2.0
1950 2000 2050 2100
10 6 km 2
10.0
Northern hemisphere September sea ice extent
Northern Hemisphere sea ice extent
RCP2.6
RCP4.5
RCP6.0
R
8.0
39 (5)
(10 6 km 2 )
6.0
4.0
29 (3)
2.0
37 (5)
0.0
1950 2000 2050 2100
1950 2000 2050 2100
RCP2.6
RCP4.5
RCP6.0
RCP8.5
(c)
Note:
8.2
Source:
This figure shows changes in northern hemisphere September sea ice extent as simulated by CMIP5 models over the 21st century under
different emissions scenarios (RCPs). Sea ice extent is defined as the total ocean area in which sea ice concentration exceeds 15 % and
is calculated on the original Global model grids. The ocean solid lines show surface the five-year running pH means under the emissions scenarios RCP2.6 (blue)
and RCP8.5 (red), based on those models that most closely reproduce the climatological mean state and 1979–2012 trend of the Arctic
sea ice, with the shading denoting the uncertainty range. The mean and associated uncertainties averaged over 2081–2100 are given for
all RCP scenarios as coloured vertical bars (right). For completeness, the CMIP5 multi-model mean for RCP2.6 and RCP8.5 is indicated
with dotted lines. The black dashed line represents nearly ice-free conditions.
12
Adapted from IPCC, 2013b (Figure SPM-7(b)).
(pH unit)
9
8.0
7.8
10
7.6
1950 2000
Year
2050 2100
RCP2.6
RCP4.5
RCP6.0
RCP8.5
7 | CMIP5 multi-model simulated time series from 1950 to 2100 for (a) change in global annual mean surface temperature relative
b) Northern Hemisphere September sea ice extent (5-year running mean), and (c) global mean ocean surface pH. Time series of projectio
e of uncertainty (shading) are shown for scenarios RCP2.6 (blue) and RCP8.5 (red). Black (grey shading) is the modelled historical evolut
l reconstructed forcings. The mean and associated uncertainties averaged over 2081−2100 are given for all RCP scenarios as colored ve
umbers of CMIP5 models used to calculate the multi-model mean is indicated. For sea ice extent (b), the projected mean and uncertai
ximum range) of the subset of models that most closely reproduce the climatological mean state and 1979 to 2012 trend of the Arctic
umber of models given in brackets). For completeness, the CMIP5 multi-model mean is also indicated with dotted lines. The dashed l
rly ice-free conditions (i.e., when sea ice extent is less than 10 6 km 2 for at least five consecutive years). For further technical details see
mary Supplementary Material {Figures 6.28, 12.5, and 12.28–12.31; Figures TS.15, TS.17, and TS.20}
Climate change, impacts and vulnerability in Europe 2016 | An indicator-based report
95