Conservation of World Heritage glacial landscapes in a changing climate: The Swiss Alps Jungfrau-Aletsch case

Many glacial landscapes on all continents are inscribed on the World Heritage List. Due to climate change, most of the glaciers are retreating rapidly, thus questioning their Outstanding Universal Value (OUV). Ice loss could indeed reduce or modify the heritage values of the UNESCO World Heritage properties where glaciers are the core of the OUV and even question their inscription on the World Heritage List. In a future with fewer or without glaciers, at least two components of the OUV of World Heritage glacial landscapes could be affected: the aesthetic value (criterion vii), which could be reduced if glaciers disappear, and the geoheritage value (criterion viii), which is partly based on current glaciological processes that would no longer exist without ice. This presentation aims to clarify what constitute the heritage values of glacial landscapes and outlines how they could evolve in a future with less (or without) ice. For two sites in the UNESCO Swiss Alps Jungfrau-Aletsch property (the Great Aletsch Glacier and the Upper Lauterbrunnen Valley), we describe the evolution of the glacial landscape using a Past-Present-Future framework. We then evaluate the present and post-glacial heritage values according to criteria used in the literature on geomorphosites. We outline two main issues: 1. The two sites are characterized by a very high palaeogeographical interest: the inherited glacial landforms around the Great Aletsch Glacier and Lake Oberhorn have allowed the reconstruction of Holocene glacial stages. In the future, the inherited landforms of high palaeogeographical interest and the para- and periglacial processes that develop in post-glacier conditions are likely to gain interest, while the dynamics of the glacier itself, which is an important part of the current geoscientific value, will decline and even be lost when the glacier disappears. As glaciers retreat, the geoscientific value will therefore depend more and more on the inherited glacial landforms, which allow the understanding of the Earth and climate history, and less and less on the glacier itself and its dynamics. As the inherited landforms can be fragile, are non-renewable and will become more central to the heritage value, their protection is an issue. 2. The aesthetic value of glacial landscapes could decrease because of the disappearance of the glacier (landscape greying). One possible adaptation could be a shift from glacier tourism, which is mainly oriented towards the contemplation of an aesthetic landscape, to geotourism, where the understanding of landscape evolution is proposed to the public.