Local changes

The extent of summer warming in the Alps is expected to be greater than in the other regions of Switzerland; at the same time, the increase in winter precipitation in that region is less pronounced. If greenhouse gas emissions continue to rise unabated, many locations in the Alps will end up below the winter zero-degree isotherm which were previously above it, and the number of days with fresh snow can be expected to decrease significantly.

Map of the Alpes with indication of the measurement stations.

In the event that greenhouse gas emissions continue to increase unchecked (RCP8.5 emission scenario), the winter zero-degree isotherm, which is currently around 800 m a.s.l., will rise by several hundred metres as a result of the warming. This means that many stations located at medium altitudes (e.g., Adelboden and Disentis) that today record on average below-zero temperatures over the winter months will experience average temperatures above 0°C by the middle of the century .

In Adelboden, for example, by the middle of this century, the average winter temperature will increase from -1.1°C today to a likely 0.7–1.9°C if greenhouse gas emissions continue to rise unabated (RCP8.5). Because of the increasing winter temperatures, the number of days with fresh snowfall will decrease significantly compared to the present. Just over half the number of fresh snowfall days compared to today are expected in Adelboden, Disentis, and Zermatt by the middle of the century.

In the summer months, the extent of the warming is generally more pronounced in the Alps than in the lowlands and tends to increase with altitude. Without climate change mitigation (RCP8.5), stations in the valleys, such as Chur, will have summer temperatures similar to those recorded on average at the warmest stations in Ticino today. The higher-altitude stations of Adelboden and Zermatt will possibly see temperatures that are typical of the Swiss Plateau. Similarly, the number of summer days (i.e., days on which the temperature exceeds 25°C) experienced in Zermatt by the middle of the century will correspond to that recorded in Bern today.

The projected changes in precipitation in winter are generally less pronounced, percentage-wise, than in the lowlands, whereas the changes in the summer months are similar in the two regions. In Adelboden, for example, the current average summer precipitation is 150 mm per month. Summer precipitation without climate change mitigation (RCP8.5) is projected to be between 110 mm and 154 mm per month by the middle of the century, thus ranging from a slight increase to a significant decrease. In the same scenario, winter precipitation is projected to range from 92 mm to 117 mm per month (compared to 93 mm per month today).

What do RCP2.6 and RCP8.5 mean? You can find an explanation of the emission scenarios here.

What does "the middle of the century" mean? You can find an explanation of the CH2018 time periods here.

Tables

In the following tables, the seasonal absolute values for temperature, precipitation, and certain climate indicators for the present (standard period 1981–2010) and for the two emission scenarios (RCP2.6 and RCP8.5) around the middle of the century (2060) are shown for a selection of monitoring stations in the Alps.

Temperature

 

Temperature in winter (°C)

Temperature in summer (°C)

Stations

m a.s.l.[C1] 

Situation today

Situation around 2060

Situation today

Situation around 2060

RCP2.6

RCP8.5

RCP2.6

RCP8.5

Adelboden

1322

-1.1

-0.5 to +0.6

+0.7 to +1.9

+13.5

+14.5 to +16.4

+16.1 to +19.4

Chur

556

+1.1

+1.7 to +3.1

+3.1 to +4.3

+18.0

+18.8 to +20.3

+20.3 to +23.0

Disentis

1197

-1.1

-0.4 to +0.9

+0.9 to +1.9

+14.6

+15.7 to +17.5

+17.2 to +20.5

Interlaken

577

+0.2

+1.0 to +2.1

+1.9 to +3.0

+17.2

+17.9 to +19.0

+19.2 to +21.0

Samedan

1708

-8.3

-7.3 to -5.8

-5.7 to -4.6

+11.1

+11.9 to +13.9

+13.2 to +15.9

Visp

639

-0.3

+0.8 to +1.9

+2.2 to +3.3

+18.4

+19.1 to +20.8

+20.5 to +23.0

Weissfluhjoch

2691

-8.1

-7.7 to -6.3

-6.4 to -5.3

+4.9

+6.0 to +7.5

+7.5 to +10.3

Zermatt

1638

-3.6

-2.8 to -1.9

-2.0 to -0.8

+12.5

+13.5 to +16.2

+15.2 to +19.1

The 'situation today' represents the actual measured seasonal average temperature over the normal period of 1981 to2010. The 'situation around 2060' gives the relevant projections for the period from 2045 to 2074.
Legend

At the Disentis monitoring station, for example, by the middle of this century (2060), the average winter temperature may increase from -1.1°C today to up to +1.9°C if greenhouse gas emissions continue to rise unabated (RCP8.5). In this scenario, an average summer temperature of between 17.2°C and 20.5°C is possible (compared to 14.6°C today). With consistent climate change mitigation (RCP2.6), the increase in winter temperatures in Disentis can be moderated, with average temperatures reaching -0.4°C to +0.9°C by 2060. In summer, temperatures will only rise to around 15.7–17.5°C.

Precipitation

 

Winter precipitation (mm/month)

Summer precipitation (mm/month)

Stations

m a.s.l.

Situation today

Situation around 2060

Situation today

Situation around 2060

RCP2.6

RCP8.5

RCP2.6

RCP8.5

Adelboden

1322

93

87 to 111

92 to 117

150

116 to 150

110 to 154

Chur

556

51

49 to 66

54 to 70

104

74 to 104

63 to 113

Disentis

1197

63

58 to 82

62 to 85

111

86 to 122

80 to 125

Interlaken

577

74

69 to 96

78 to 98

134

96 to 136

78 to 132

Samedan

1708

27

28 to 39

26 to 41

88

66 to 100

65 to 106

Visp

639

52

48 to 65

52 to 69

43

34 to 49

29 to 53

Weissfluhjoch

2691

94

86 to 111

94 to 120

175

127 to 167

110 to 175

Zermatt

1638

41

37 to 60

37 to 53

61

43 to 67

44 to 65

The ‘situation today’ represents the actual measured seasonal average precipitation over the normal period of 1981 to 2010. The ‘situation around 2060’ gives the relevant projections for the period from 2045 to 2074.
Legend

At the Adelboden monitoring station, the current average precipitation is 150 mm per month during the summer months. During the period around 2060, the summer precipitation trend without any climate change mitigation (RCP8.5) shows a decrease: Between 110 mm and 154 mm per month can be expected. In the same scenario, the winter precipitation trend indicates a likely increase from 93 mm to 92–to117 mm per month. If comprehensive measures are implemented to reduce greenhouse gas emissions (RCP2.6), the changes in precipitation can be mitigated slightly. In summer, precipitation would then be between 116 mm and 150 mm per month (compared to 150 mm per month today), and in winter, between 87 mm and 111 mm per month (compared to 93 mm per month today).

Summer days

Stations

m a.s.l.

Summer days now

Summer days around 2060

RCP2.6

RCP8.5

Adelboden

1322

7

11 to 23

23 to 61

Chur

556

49

58 to 73

76 to 102

Disentis

1197

19

28 to 41

43 to 75

Interlaken

577

39

50 to 64

65 to 91

Samedan

1708

2

5 to 13

14 to 40

Visp

639

64

76 to 97

97 to 127

Weissfluhjoch

2691

0

0

0 to 1

Zermatt

1638

6

11 to 27

27 to 76

‘Summer days now’ represents the actual recorded number of summer days per year, averaged over the normal period of 1981 to 2010. ‘Summer days around 2060’ gives the relevant projections for the period from 2045 to 2074.
Legend

Currently, the monitoring station of Interlaken observes an average of 39 summer days (temperature of at least 25°C) per year. Without climate change mitigation (RCP8.5), there could be up to 91 summer days per year in Interlaken by the middle of this century (2060). With consistent implementation of climate change mitigation (RCP2.6), the increase would be less drastic, up to 64 summer days.

Tropical nights

Stations

m a.s.l.

Tropical nights now

Tropical nights around 2060

RCP2.6

RCP8.5

Adelboden

1322

0.0

0.0 to 0.1

0.0 to 2.9

Chur

556

0.1

0.6 to 2.5

2.8 to 15.2

Disentis

1197

0.0

0.0 to 0.2

0.1 to 3.4

Interlaken

577

0.0

0.1 to 1.0

0.8 to 5.6

Samedan

1708

0.0

0.0

0.0

Visp

639

0.1

0.0 to 0.4

0.3 to 4.0

Weissfluhjoch

2691

0.0

0.0

0.0

Zermatt

1638

0.0

0.0

0.0 to 0.2

‘Tropical nights now’ represents the actual recorded number of tropical nights per year, averaged over the normal period of 1981–2010. ‘Tropical nights around 2060’ gives the relevant projections for the period from 2045 to 2074.
Legend

At the Chur monitoring station, tropical nights are an exception in the current climate (over the normal period of 1981–2010), with 0.1 per year. By the middle of this century (2060), there could be 15.2 tropical nights per year at this station. With consistent climate change mitigation (RCP2.6), the average number of tropical nights would be limited to up to 2.5 per year.

Frost days

Stations

m a.s.l.

Frost days now

Frost days around 2060

RCP2.6

RCP8.5

Adelboden

1322

136

105 to 131

88 to 110

Chur

556

84

57 to 77

45 to 61

Disentis

1197

128

99 to 123

83 to 101

Interlaken

577

100

74 to 96

60 to 76

Samedan

1708

235

199 to 222

175 to 200

Visp

639

114

87 to 110

71 to 90

Weissfluhjoch

2691

263

226 to 250

195 to 223

Zermatt

1638

173

150 to 171

132 to 153

‘Frost days now’ represents the actual recorded number of frost days per year, averaged over the normal period of 1981–2010. ‘Frost days around 2060’ gives the relevant projections for the period from 2045 to 2074.
Legend

The monitoring station of Samedan observes an average of 235 frost days (minimum temperature below 0°C) per year. Without climate change mitigation (RCP8.5), the number of frost days in Samedan is projected to decrease to 175–200 per year by the middle of this century (2060). With consistent climate change mitigation, there will be a smaller reduction in the number of frost days per year, to 199–222.

Days with fresh snowfall

Stations

m a.s.l.

Days with fresh snowfall now

Days with fresh snowfall around 2060

RCP2.6

RCP8.5

Adelboden

1322

42

24 to 40

18 to 32

Chur

556

13

6 to 15

4 to 11

Disentis

1197

34

15 to 28

11 to 23

Interlaken

577

17

13 to 24

9 to 19

Samedan

1708

28

20 to 36

18 to 29

Visp

639

11

7 to 14

4 to 11

Weissfluhjoch

2691

105

86 to 103

76 to 93

Zermatt

1638

30

17 to 29

14 to 24

‘Days with fresh snowfall now’ represents the actual recorded number of fresh snowfall days per year, averaged over the normal period of 1981 to 2010. ‘Days with fresh snowfall around 2060’ gives the relevant projections for the period from 2045 to 2074.
Legend

During the normal period of 1981 to 2010, the Weissfluhjoch monitoring station recorded an average of 105 days with fresh snowfall (a minimum of 1 mm of precipitation falling in the form of snow) per year. Without climate change mitigation (RCP8.5), the number of days with fresh snowfall per year will decrease to 76–93 at the Weissfluhjoch station by the middle of the century (2060). With consistent climate change mitigation (RCP2.6), there will be a smaller reduction in the number of days of fresh snowfall per year, to 86–103.

Charts

The interactive charts for all indicators use Zermatt as an example. You can find the figures for other stations in the CH2018 web Atlas.

Zermatt

What do RCP2.6 and RCP8.5 mean? You can find an explanation of the emission scenarios here.

Last modification 11.12.2018

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