The consequences of global climate change in Switzerland can be seen clearly with the help of climate indicators. In the lower-lying areas to the north and south of the Alps in particular, the numbers of summer days and tropical nights are increasing. Currently, tropical nights are still the exception in Switzerland, but we can expect between 5 and 20 tropical nights per year in central Switzerland by the middle of this century if greenhouse gas emissions continue unchecked at the same rate as today. Cold days are becoming rarer. The numbers of frost days and days with fresh snowfall are falling across the board. In the Alps, we can expect to see a reduction in days with fresh snow by up to 30 a year. With climate change mitigation measures, however, these consequences can be significantly reduced.
The significant rise in temperature is not the only indicator of future climate change. There are many additional climate indicators, such as the number of summer days or days with fresh snow, that allow us to understand the climate and how it is changing. The maps below show the spatial distributions of the average numbers of summer days, tropical nights, frost days, and days with fresh snowfall per year. Each map shows the average values for the normal period from 1981 to 2010 and, on the right, the regional projections for the period from 2045 to 2074. Clicking on one of the two buttons – RCP2.6 or RCP8.5 – switches between the different emission scenarios.
What do RCP2.6 and RCP8.5 mean? You can find an explanation of the emission scenarios here.
Summer days
The situation today
At present, the average number of summer days on the Swiss Plateau is between 30 and 60 days a year. Lower-lying regions in Ticino have up to 85 summer days.
The situation around 2060
By 2060, the average number of summer days on the Swiss Plateau is expected to rise to 60–95 without climate change mitigation (RCP8.5), and potentially to over 120 in the valleys in Ticino. With climate change mitigation (RCP2.6), the number of summer days per year on the Swiss Plateau can be restricted to 40–75. In Ticino, 100 days would only be exceeded in the lowest-lying Areas.
Tropical nights
The situation today
Currently in Switzerland, tropical nights are the exception almost everywhere across the country. In most areas, tropical nights do not even occur once a year. Ticino and the Lake Geneva region are the most likely to experience such warm nights.
The situation around 2060
In the future, tropical nights will become far more common than they are now. In central Switzerland, up to 15 tropical nights per year can be expected by the middle of this century without climate change mitigation (RCP8.5). In the lower-lying regions of Ticino, the number of tropical nights is expected to be 25–46; this would mean that every third day in summer would have a tropical night. With climate change mitigation (RCP2.6), the number of tropical nights on the Swiss Plateau could be kept down to 1–4 per year; in Ticino, slightly more than 20 would be expected.
Frost days
The situation today
In the lower-lying areas of central Switzerland, there are currently about 70 frost days per year. In the Alpine foothills, this figure is around 120 days, and in the Alps themselves (with the exception of a few valleys), more than one-third of all days in the year have a minimum temperature below 0°C.
The situation around 2060
In the western part of central Switzerland and in Ticino, the number of frost days would fall to fewer than 50 a year by 2060 without climate change mitigation (RCP8.5). This is the equivalent of about one month fewer days with frost. The largest absolute reduction in frost days – over 50 days – will be found in the high mountain regions. With climate change mitigation (RCP2.6), the reduction in the number of frost days in the high Alps can be restricted to around 30 days.
Days with fresh snow
The situation today
In the central high Alps, it currently snows on average over 100 days per year. In the Alpine foothills, around 40 to 80 days of snowfall per year are typical, and in the lowlands, between 10 and 30 days a year.
The situation around 2060
Without climate change mitigation (RCP8.5), the number of days with snowfall in the Alps can be expected to fall by around 30. This means that there would be less than 80 days per year with fresh snowfall in many areas. In central Switzerland, the number of days with fresh snowfall is expected to reduce to significantly fewer than 20; in the low-lying areas of Ticino, it will hardly snow at all. With climate change mitigation (RCP2.6), in slightly elevated areas of central Switzerland, more than 20 days of fresh snowfall are possible.
Last modification 15.11.2018
