Disappearing World Heritage Glaciers as a Keystone of Nature Conservation in a Changing Climate

Abstract

Since 1972, the United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Convention aims to identify and protect sites of Outstanding Universal Value for future generations. However, growing impacts of climate change are of the utmost concern for the integrity of many sites. Here, we inventory the glaciers present in natural World Heritage sites for the first time. We found 19,000 glaciers in 46 sites located all over the world. We analyze their recent evolution, current state, and project their mass change over the 21st century. Our results are based on a comprehensive review of the literature as well as a state-of-the-art glaciological model for computing glacier responses up to 2100. Illustrating the strong influence of CO 2 emission scenarios and human actions on future ice loss magnitude, we project the wastage of 33% to 60% of the 2017 cumulative ice volume of 12,000 km 3 of World Heritage glaciers by 2100. Furthermore, we expect complete glacier extinction in 8 to 21 of the investigated World Heritage sites until the end of the century, depending on the climate scenario. We suggest that World Heritage glaciers should be considered as analogs to endangered umbrella, keystone, and flagship species, whose conservation would secure wider environmental and social benefits at global scale. Plain Language SummaryThe World Heritage convention aims at protecting the Earth's outmost assets and commits humanity to transmit them to future generations. However, many World Heritage sites are affected by anthropogenic climate change. Here, we present the first study on the glaciers located within the natural World Heritage sites. We inventoried 19,000 World Heritage glaciers and projected their mass changes over the 21st century. The results emphasize that major glacier decline will occur in these iconic sites in future decades. Nevertheless, ice loss magnitude will vary by a factor of 2 according to CO 2 emission scenarios and thus human activities. This study points out how the conservation of World Heritage glaciers could serve as a leverage and a target to tackle the unprecedented issue of climate change. Glaciers are more than disappearing passive climatic indicators. They are key components of planetary ecosystems that influence global climate and sea level, as well as water fluxes, human activities, or biodiversity at the regional scale. The conservation of these iconic endangered features could thus mobilize global-scale conservation and climate mitigation benefits. In this context, we show how drastic reduction of emissions will rapidly curb melt rates and safeguard a large glacier volume on the long term.

Global warming accelerates uptake of atmospheric mercury in regions experiencing glacier retreat

“…The current rate of Hg mass loss in subpolar and alpine glacier regions is estimated to be 0.4 to 0.6 Mg y −1 , assuming a water loss rate of 200 to 300 Gt y −1 (31) and an mean Hg concentration of 2 pg g −1 (SI Appendix, Table S15). By 2100, the total Hg mass loss from glacier melt is projected to be ∼95 Mg (∼47,000 Gt water loss because of higher glacier retreat rates in the future [31]), while the Hg mass captured by the new ecosystems in glacierretreated areas is ∼2 times greater (∼300 Mg based on the present-day mean Hg 0 accumulation rate and predicted new glacier-retreated areas in the next 100 y [31,35]) (detailed in SI Appendix). Therefore, while glacier melting releases Hg originally locked in the ice into the atmosphere and downstream ecosystems (12,13,29), the establishment of new vegetative ecosystems will counter the release through an opposite process that captures atmospheric Hg through glacier-to-vegetation succession.…”

Peatland Contribution to Stream Organic Carbon Exports From a Montane Watershed

“…Moreover, mountainous areas are expected to be strongly impacted by climate change in the coming years (Nogués-Bravo et al, 2007;Pachauri & IPCC, 2008), which will certainly affect their stream organic carbon specific fluxes. Increasing temperatures and precipitation changes will cause severe shifts in mountainous hydrological regimes (Beniston, 2006;Eckhardt & Ulbrich, 2003;Gobiet et al, 2014) by reducing snow and ice pack (Barry, 1990;Bosson et al, 2019;Zemp et al, 2006). They will also modify the catchment land cover by enhancing thermophilic plant communities and increasing vegetation in alpine climatic belts (Gottfried et al, 2012;Rogora et al, 2018).…”

Large hydropower and water-storage potential in future glacier-free basins

“…4). The unique nature of glacierized environments, for example, has qualified many sites for UNESCO World Heritage or World Protected Area status 27 (see Methods for definitions). This results in a suitability score of zero for many sites in New Zealand (80% of the identified potential; Extended Data Fig.…”