Climate change impacts and vulnerability in Europe 2016

Changes in the climate system
Projections
northern hemisphere snow cover will continue to
shrink and snow seasons shorten as temperatures
rise (Vaughan et al., 2013), although in the coldest
regions snowfall can also increase in the middle of
winter (Hanssen-Bauer et al., 2015; Räisänen, 2016).
The multi-model mean from the CMIP5 modelling
exercise projects changes in March/April snow
cover extent in the northern hemisphere during the
21st century ranging from 7 % for a low emissions
scenario (RCP2.6) to 25 % for a high emissions
scenario (RCP8.5) (Figure 3.16). The projected snow
mass generally follows the snow cover extent with
an estimated range of reduction from about 10 % for
RCP2.6 to about 30 % for RCP8.5; projected reductions
in the duration of the snow season range from about
10 days for RCP2.6 to about 40 days for RCP8.5
(Brutel-Vuilmet et al., 2013).
Specific regional studies suggest significant reductions
in snow mass in, for example, the Alps in general (Steger
et al., 2013; Schmucki et al., 2015), Switzerland (BAFU,
2012), the alpine range of Italy (Soncini and Bocchiola,
2011), the Pyrenees (López-Moreno et al., 2009), Norway
(Hanssen-Bauer et al., 2015), the Turkish mountains
(Özdoğan, 2011) and the Balkan mountains (FAO,
2010). These changes can have dramatic downstream
effects as melt water contributes up to 60–70 % to
annual river flows. Despite the projected decrease in
long‐term mean snow mass in the northern hemisphere,
model simulations indicate occasional winters of heavy
snowfall, but these become increasingly uncommon
towards the end of the 21st century.
Figure 3.16
Projected changes in northern hemisphere spring snow cover extent
Spring snow cover extent (%)
10
5
0
– 5
– 10
– 15
– 20
– 25
– 30
– 35
Note:
Source:
1980
1985
1990
1995
2000
2005
2010
2015
2020
2025
2030
2035
2040
2045
2050
2055
2060
2065
2070
2075
2080
2085
2090
2095
2100
H AVG RCP2.6 RCP4.5 RCP6.0 RCP8.5
This figure shows the northern hemisphere spring (March to April average) snow cover extent based on the CMIP5 ensemble for actual
emissions (up to 2005) and different forcing scenarios (RCPs). Values are given relative to the 1986–2005 reference period (H AVG). Thick
lines mark the multi-model average and shading indicates the inter-model spread (one standard deviation).
Adapted from IPCC (2013a, Figure 12.32). Data were provided by Gerhard Krinner (Laboratoire de Glaciologie et Géophysique de
l'Environnement, France).
104 Climate change, impacts and vulnerability in Europe 2016 | An indicator-based report