Global Disappearance of Tropical Mountain Glaciers: Observations, Causes, and Challenges

Abstract

This article reviews the current status of tropical glaciers in the South American Andes, East Africa, and Australasia by shedding light on past, present, and future glacier coverage in the tropics, the influence of global and regional climates on the tropical glaciers, the regional importance of these glaciers, and challenges of ongoing glacier recessions. While tropical glaciers have predominantly receded since the Little Ice Age, the rate of shrinkage has accelerated since the late 1970s as a result of climate changes. As a result, socio-ecological implications occur around ecosystem health, natural hazards, freshwater resources, agriculture, hydropower, mining, human and animal health, traditions and spirituality, and peace.

The end of the eternal snows: Integrative mapping of 100 years of glacier retreat in the Venezuelan Andes

“…It is difficult to predict how much longer it will be before the final disappearance of Humboldt Peak glacier, especially because previous predictions for the remaining low-elevation glaciers in Colombia and Venezuela have proven too drastic (e.g., Poveda and Pineda 2009) and given the lack of detailed climatic data and glaciological measurements in Venezuela (i.e., lack of data on mass balance, ice thickness, snowfall, etc.). However, we can be certain that Venezuela will be the first Andean country to lose all of its glaciers in the next few years, and likely among the first in the world, in a close race with Indonesia's Puncak Jaya Peak glaciers Mount Kenya and Stanley Peak in the Rwenzori mountains (Permana et al 2019;Veettil and Kamp 2019). Thus, studying the trajectory of Venezuelan glacier retreat constitutes a unique opportunity to promote interest in and further research on the consequences of climate change in the tropical Andes, thereby strengthening conservation and climate change adaptation initiatives.…”

Disappearing Kilimanjaro snow—Are we the last generation to explore equatorial glacier biodiversity?

“…Only a few places on Earth still host equatorial and near equatorial ice—Africa (Kenya, Tanzania, Uganda), New Guinea, and the largest equatorial ice cover, South America (Ecuador, Colombia; Figure ). These glaciers are all located at least at 4,000 m a.s.l., higher than many tropical glaciers in South America or temperate glaciers in the Caucasus or Alps (Veettil & Kamp, ). Considering the hundreds of studies devoted to microbial communities and invertebrates on glaciers and snow in the Arctic, Antarctic, Third Pole (Hindu Kush–Karakoram–Himalayan), and other high mountain regions (Cook et al, ; Hodson et al, ; Hotaling, Hood, & Hamilton, ; Kaczmarek, Jakubowska, Celewicz‐Gołdyn, & Zawierucha, ; Zawierucha et al, ), the scarce knowledge collected from tropical icy islands seems alarming, from the perspective of biodiversity protection.…”

“…Considering the hundreds of studies devoted to microbial communities and invertebrates on glaciers and snow in the Arctic, Antarctic, Third Pole (Hindu Kush–Karakoram–Himalayan), and other high mountain regions (Cook et al, ; Hodson et al, ; Hotaling, Hood, & Hamilton, ; Kaczmarek, Jakubowska, Celewicz‐Gołdyn, & Zawierucha, ; Zawierucha et al, ), the scarce knowledge collected from tropical icy islands seems alarming, from the perspective of biodiversity protection. Equatorial and tropical glaciers (e.g., in central Asia, South America) are considered a source of freshwater maintaining downstream animals and plants assemblages (Bosson, Huss, & Osipova, ; Milner et al, ; Veettil & Kamp, ). Also equatorial, glacier‐fed streams present unique hydraulic patterns when compared to temperate regions, and taxon richness in glacier‐fed streams of the Ecological Reserve of Antisana (Ecuador) will be significantly reduced following glacier shrinking (Cauvy‐Fraunié et al, ).…”

“…Due to high altitude, their surface is irradiated intensively, they represent different geological settings, and mostly they are not directly surrounded by high mountains (like glaciers in Svalbard or the Alps), which decreases the delivery of local mineral and organic material on the glacier surface. The glaciated areas in Colombia and Ecuador belong to the inner tropics, with a year‐round precipitation pattern that lacks any seasonality (Veettil & Kamp, ). These climatic and geological differences likely shape different microbial assemblages in comparison with polar or alpine glaciers.…”

Biological albedo reduction on ice sheets, glaciers, and snowfields

“…A variety of temperate regions have also been overlooked, including subranges of the Rocky Mountains in North America (e.g., Teton Range, USA), the Caucasus Mountains in eastern Europe (e.g., Makowska et al, 2020), and similar localities. Rapidly receding tropical glaciers are also urgent targets for ecological studies (Veettil and Kamp, 2019;Zawierucha and Shain, 2019). Tropical glaciers, for instance, show far greater variability in terms of climate sensitivity (Kaser, 2001;Kaser et al, 2004) compared to mid-and high-latitude glaciers and differ from higher latitude glaciers by the absence of seasonal temperature cycles (monthly mean temperatures vary by less than 5ºC) and extended periods of freezing (Lentini et al, 2011).…”