Editing Alps (section)

== Climate ==
{{main|Climate of the Alps|High Alps}}

The Alps are a classic example of what happens when a [[Temperateness|temperate]] area at lower altitude gives way to higher-elevation terrain. Elevations around the world that have cold climates similar to those of the [[polar region]]s have been called [[Alpine climate|Alpine]]. A rise from sea level into the upper regions of the atmosphere causes the temperature to decrease (see [[adiabatic lapse rate]]). The effect of mountain chains on prevailing winds is to carry warm air belonging to the lower region into an upper zone, where it expands in volume at the cost of a proportionate loss of temperature, often accompanied by precipitation in the form of snow or rain.{{sfn|Coolidge|Lake|Knox|1911|p=737}} The height of the Alps is sufficient to divide the weather patterns in Europe into a wet north and dry south because moisture is sucked from the air as it flows over the high peaks.<ref>Fleming (2000), 3</ref>

[[File:Aletschgletscher mit Pinus cembra1.jpg|thumb|The [[Aletsch Glacier]] with pine trees growing on the hillside (2007; the surface is {{cvt|180|m}} lower than 150 years ago)]]

The severe weather in the Alps has been studied since the 18th century; particularly the weather patterns such as the seasonal [[foehn wind]]. Numerous weather stations were placed in the mountains early in the early 20th century, providing continuous data for climatologists.<ref name="Ceben 22–24">Ceben (1998), 22–24</ref> Some of the valleys are quite arid such as the [[Aosta Valley]] in Italy, the [[Maurienne]] in France, the [[Valais]] in Switzerland, and northern [[Tyrol (federal state)|Tyrol]].<ref name="Ceben 22–24" />

The areas that are not arid and receive high precipitation experience periodic flooding from rapid snowmelt and runoff.<ref name="Ceben 1998, 31"/> The mean precipitation in the Alps ranges from a low of {{cvt|2600|mm|in}} per year to {{cvt|3600|mm|in}} per year, with the higher levels occurring at high altitudes. At altitudes between {{cvt|1000|and|3,000|m}}, snowfall begins in November and accumulates through to April or May when the melt begins. [[Snow line]]s vary from {{cvt|2400|to|3,000|m}}, above which the snow is permanent and the temperatures hover around the freezing point even during July and August. High-water levels in streams and rivers peak in June and July when the snow is still melting at the higher altitudes.<ref>Ceben (1998), 34–36</ref>

The Alps are split into five climatic zones, each with different vegetation. The climate, plant life, and animal life vary among the different sections or zones of the mountains. The lowest zone is the colline zone, which exists between {{cvt|500|and|1000|m}}, depending on the location. The [[montane]] zone extends from {{cvt|800|to|1,700|m}}, followed by the sub-Alpine zone from {{cvt|1600|to|2,400|m}}. The Alpine zone, extending from [[tree line]] to the snow line, is followed by the glacial zone, which covers the glaciated areas of the mountain. Climatic conditions show variances within the same zones; for example, weather conditions at the head of a mountain valley, extending directly from the peaks, are colder and more severe than those at the mouth of a valley which tend to be less severe and receive less snowfall.<ref>Viazzo (1980), 17</ref>

;Climate change
[[File:Duration of the yearly snow cover ring-width reconstruction together with modelled record for the Alps.webp|thumb|200px|Shrinkage of snow cover duration, starting ~end of the 19th century<ref name="10.1038/s41558-022-01575-3"/>]]
Various models of [[climate change]] have been projected into the 22nd century for the Alps, with an expectation that a trend toward increased temperatures will have an effect on [[Effects of climate change#Ice and snow|snowfall, snowpack, glaciation, and river runoff]].<ref>Benniston (2011), 3–4</ref><ref>{{Cite web |title=IPCC regional fact sheet - Mountains |url=https://www.ipcc.ch/report/ar6/wg1/downloads/factsheets/IPCC_AR6_WGI_Regional_Fact_Sheet_Mountains.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.ipcc.ch/report/ar6/wg1/downloads/factsheets/IPCC_AR6_WGI_Regional_Fact_Sheet_Mountains.pdf |archive-date=2022-10-09 |url-status=live}}</ref> Significant changes, of both natural and anthropogenic origins, have already been diagnosed from observations,<ref>{{Cite journal |last1=Huss |first1=Matthias |last2=Hock |first2=Regine |last3=Bauder |first3=Andreas |last4=Funk |first4=Martin |date=May 1, 2010 |title=100-year mass changes in the Swiss Alps linked to the Atlantic Multidecadal Oscillation |journal=Geophysical Research Letters |language=en |volume=37 |issue=10 |pages=L10501 |doi=10.1029/2010GL042616 |issn=1944-8007 |bibcode=2010GeoRL..3710501H |url=http://doc.rero.ch/record/20213/files/hus_msc_sm.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://doc.rero.ch/record/20213/files/hus_msc_sm.pdf |archive-date=2022-10-09 |url-status=live |doi-access=free}}</ref><ref>{{Cite journal |last1=Zampieri |first1=Matteo |last2=Scoccimarro |first2=Enrico |last3=Gualdi |first3=Silvio |date=January 1, 2013 |title=Atlantic influence on spring snowfall over the Alps in the past 150 years |journal=Environmental Research Letters |language=en |volume=8 |issue=3 |pages=034026 |doi=10.1088/1748-9326/8/3/034026 |issn=1748-9326 |doi-access=free |bibcode=2013ERL.....8c4026Z}}</ref><ref>{{Cite journal |last1=Zampieri |first1=Matteo |last2=Scoccimarro |first2=Enrico |last3=Gualdi |first3=Silvio |last4=Navarra |first4=Antonio |date=January 15, 2015 |title=Observed shift towards earlier spring discharge in the main Alpine rivers |journal=Science of the Total Environment |series=Towards a better understanding of the links between stressors, hazard assessment and ecosystem services under water scarcity |volume=503–504 |pages=222–232 |doi=10.1016/j.scitotenv.2014.06.036 |pmid=25005239 |hdl=2122/9055 |bibcode=2015ScTEn.503..222Z}}</ref> including a 5.6% reduction per decade in snow cover duration over the last 50 years, which also highlights [[climate change adaptation]] needs due to impacts on the climate and regional socio-economic activities.<ref name="10.1038/s41558-022-01575-3">{{cite journal |last1=Carrer |first1=Marco |last2=Dibona |first2=Raffaella |last3=Prendin |first3=Angela Luisa |last4=Brunetti |first4=Michele |title=Recent waning snowpack in the Alps is unprecedented in the last six centuries |journal=Nature Climate Change |date=February 2023 |volume=13 |issue=2 |pages=155–160 |doi=10.1038/s41558-022-01575-3 |bibcode=2023NatCC..13..155C |language=en |issn=1758-6798 |doi-access=free|hdl=11577/3477269 |hdl-access=free }}</ref>