Unearthing Rock Glaciers: Hidden, Hydrological Landforms

Rock glaciers are distinctive, geomorphological landmasses composed of rock, ice, snow, mud, and water. Unlike exposed ice glaciers, the majority of ice and water is located within the rock glaciers’ underground permafrost. Above-ground characteristics of rock glaciers include unique tongue-shaped terminations, rock debris, and mountainous ridges.

Rock glaciers are frequently overshadowed by neighboring ice glaciers and overlooked due to their hidden nature. Although often forgotten, rock glaciers are common features in many mountain regions of the world and provide supplementary streamflow when water is needed most during dry, warm years.

Cross-section of a rock glacier which includes the above-ground layer, the permafrost core, and the hydrological system (Source: Schaffer et al.)

A Chilean-based scientific review team, from the Center for Advanced Studies in Arid Zones (CEAZA), published a study that evaluates the hydrological value of rock glaciers in the semiarid Andes (SA). Rock glaciers in the SA are rarely studied, so this group, led by scientist Nicole Schaffer, attempts to shed light on the region’s hidden landforms.

The SA is “a transition zone between the extremely arid region north of 25°S and the humid climate south of 40°S … over the twentieth century, total precipitation has declined and desertification has been recognized internationally as a critical problem,” states Schaffer et al.

Using published data sampling from the La Laguna Basin in Chile, the review team estimates glacial water contributions of the Llano de las Liebres, Las Tolas, Empalme, and Tapado Rock Glaciers using discharge measurements. Water discharge measurements collect the volume of moving water down a stream per unit of time.

Overall, rock glaciers in the semiarid Andes are believed to provide meaningful contributions to streamflows. The team’s findings indicate that the rock glaciers in the La Laguna Basin contribute between 9 to 20 percent of the total streamflow in the region.

How Will Rock Glaciers Respond to Warming Temperatures?

Through climate projections and historical evidence, the scientific community believes that rock glaciers will likely be less vulnerable to climate change.

North Cascades, Washington National Park (Source: Richard Droker, Flickr)

Due to the sheer size and high elevation of rock glaciers in the Chilean Andes, there will likely be delayed response times to climate change. As temperatures increase, smaller and lower elevation rock glaciers will likely thaw before substantial, high mountain rock glaciers.

U.S. Forest Service scientist Connie Millar studies both the historical and ongoing influences of climate change on rock glaciers in the western U.S. Millar’s research includes hydrological studies of rock glaciers in the Great Basin and ice glacier canyon mapping in the Sierra Nevada.

Millar said: “[Rock glaciers may] lag in response to climate change and maybe it’s more on scale of hundreds of years rather than thousands of years and it depends of course on where it is … and how quickly and how they respond to warming.”

North Cascades, Washington National Park (Source: Richard Droker, Flickr)

Alexander Brenning, scientist at Friedrich Schiller University Jena in Germany, also offers insight on the potential impacts of climate change.

Brenning shared: “Rock glaciers are complex systems that may react in various ways. The most worrying of all scenarios is the acceleration and even collapse of rock glaciers. Climatic warming may play a role in this scenario since it is expected to increase the availability of liquid water within the otherwise frozen rock glacier.”

Ultimately, rock glacial responses to climate change are highly variable and dependent on glacial size, elevation, and geographical location. To learn more about the climatic impacts, greater awareness of rock glaciers and further in-depth research is required.

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Roundup: New Scholarships, Planetary Thresholds and Threatened Glaciers

New Fulbright Scholarships for Quechua Speakers

Translated from La República: “Studying in the United States is possible if you really want it. This is stated by Laura Balbuena, executive director of the Fulbright Commission in Peru, the entity in charge of the educational and cultural exchange between the United States of America and our country… One scholarship offered by the Fulbright Commission this year is aimed at Quechua-speaking professionals. Through the Foreign Language Teaching Assistant (FLTA) scholarship or Foreign Language Teaching Assistant, it is intended that Peruvian graduates who have mastery of the Quechua language – as a first language or learned – are assistants to the chair of this course that are offered in certain U.S. universities.”

Learn more here.

Laura Balbuena, executive director of the Fulbright Commission in Peru, announces scholarships for Quechua speaker in Peru (Source: La República).


Crossing Planetary Thresholds

From PNAS: “ If the world’s societies want to avoid crossing a potential threshold that locks the Earth System into the Hothouse Earth pathway, then it is critical that they make deliberate decisions to avoid this risk and maintain the Earth System in Holocene-like conditions…Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. ”

Read more here.

Rock glaciers of the European Alps. Alpine glaciers are considered to be one of the tipping points (Source: M Barton/Flickr).


Columbia’s Glaciers Face Extinction

From The City Paper Bogota: “Climate change is taking a devastating toll on Colombia’s glaciers, according to the country’s Institute of Hydrology, Meteorology and Environmental Studies – IDEAM. In a study released last month, within the next 30 years, the six remaining glaciers that cover the peaks of Colombia’s Nevados will disappear if the ice continues to melt at current rates.”

Read the full article here.

View of Nevado del Huila in Colombia. Four of Colombia’s six glaciers are found on volcanoes (Source: Joz3.69/Flickr).

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Rock Glaciers Help Protect Species in a Warmer Climate

Grasses and other plant species often thrive on the periphery of major glaciers on active rock periglaciers (Source: Savannah Theilbar).

In a recent study by Duccio Tampucci et al., rock glaciers in the Italian Alps have been shown to host a wide variety of flora and fauna, supporting plant and arthropod species during temporary decadal periods of climatic warming. Certain species that thrive in cold conditions have been prone to high environmental stress during warm climate stages in the past, but given the results of Tampucci’s research, it is now clear that these species may be able to survive in periglacial settings on the edge of existing glaciers.

One of many species of arthropods equipped to survive in cold temperatures on glacier surfaces. (Source: Rebecca Rendon).

Active rock glaciers, commonly found on the border of larger glaciers and ice sheets, are comprised of coarse debris with intermixed ice or an ice-core. The study has valuable implications on how organisms may respond to changes in temperature, offering a possible explanation for species’ resiliency.

Jonathan Anderson, a retired Glacier National Park ranger, spoke to GlacierHub about the importance of periglacial realms in providing a habitat for animals displaced by modern climate change. “In the years spent in and around the park, it’s clear that more and more animals are feeling the impact of climate change and global warming,” he said. “The areas surrounding the larger glaciers are becoming even more important than before and are now home to many of the species that lived on the receded glacier.”

In their study, Tampucci and team analyzed abiotic dimensions of active rock glaciers such as ground surface temperature, humidity and soil chemistry, as well as biotic factors related to the species abundance of plants and arthropods. This data was then compared to surrounding iceless regions characterized by large scree slopes (small loose stones covering mountain slopes) as an experimental control for the glaciated landforms of interest. Comparisons between these active scree slopes and rock glaciers revealed similar soil geochemistry, yet colder ground surface temperatures existed on the rocky glaciers. Thus, more cold-adapted species existed on rock glaciers.

The Ortles-Cevedale Massif where a large portion of Tampucci et al.’s study took place (Source: Parks.it).
The Ortles-Cevedale Massif where a large portion of Tampucci et al.’s study took place (Source: Parks.it).

The distribution of plant and arthropod species was found to be highly variable, dependent upon soil pH and the severity of mountain slope-instability. This variability is because the fraction of coarse debris and quantity of organic matter changes with the landform’s activity, or amount of mass wasting occurring downslope. The study notes that the heterogeneity in landforms in mountainous regions augments the overall biodiversity of the region.

Anderson affirmed this idea, noting, “The difference in habitats between glaciated terrain and the surrounding, more vegetated regions is crucial for allowing a wide range of animals to coexist.” This variety of landforms contributes to a wide variety of microclimates in which ecologically diverse organisms can reside in close proximity.

Cold-adapted species are likely the first to be affected by region-wide seasonal warming. As temperatures increase, cold-weather habitats are liable to reduce in size and shift to higher altitudinal belts, resulting in species reduction and possible extirpation. Tampucci et al.’s study affirmed the notion that active rock glaciers serve as refugia for cold-adapted species due to the landscape’s microclimate features.

A view of the shrinking alpine-glacial environment that many species call home (Source: Daniel Rojillo).

The local periglacial environment in the Italian Ortles-Cevedale Massif, for example, was shown to be decoupled from greater regional climate, with sufficient thermal inertia (resistance to temperature change) to support cold-adapted species on a decadal timescale.

Despite the conclusive findings that largely affirm previous assumptions about biodiversity in active rock glaciers, the authors carefully point out that the glacier’s ability to serve as refugia for certain species depends entirely on the length of the warm-climate stage, which can potentially last for millennia. Additionally, the macroclimatic context in which the glaciers reside is important and can influence the landform’s thermal inertia, affecting the temporal scale at which the landscape can shelter cold-climate plants and arthropods.

The ice crawler Grylloblatta campodeiformis is another example of a cold-adapted arthropod species (Source: Piotr Naskrecki).

The idea that certain periglacial regions may be the saving grace for small plants and animals is encouraging, yet these landforms fail to offer a permanent solution for conservation ecologists. Although active rock glaciers can harbor cold-adapted species for lengths of time, when an organism is forced to depend upon an alpine microclimate, it has become geographically isolated. In this scenario, the degree to which immediately surrounding terrain is inhospitable governs the species’ extinction risk.

“It’s really important to keep in mind that although certain species are adaptable and resilient, every organism has a limit,” Anderson told GlacierHub. “If the local climate continues to warm, these species will likely die in a few generations.” This means that although certain species of arthropods, for example, may be able to survive in undesirably warm conditions, this climatic shift still influences their long-term extinction risk.

While periglacial landforms may play a valuable role in protecting cold-adapted species in temporary periods of climatic warming, a large variety of external factors can influence the length of time an organism may survive in any given microclimate. The understanding that active-rock glaciers can effectively protect a range of plants and arthropods has valuable implications for conservation biologists and biogeographers, offering insight into possible explanations for cold-adapted species resiliency in historical episodes of climatic warming.

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Roundup: Rock Glaciers, Ice Tongues and Flood Warnings

Roundup: Rock Glaciers, Floating Glaciers, and Flood Warnings

Ecology of Active Rock Glaciers

From Boreas: “Active rock glaciers are periglacial landforms (areas that lie adjacent to a glacier or ice sheet that freeze and thaw) consisting of coarse debris with interstitial ice (ice formed in the narrow space between rocks and sediment) or ice-core. Recent studies showed that such landforms are able to support plant and arthropod life and could act as warm-stage refugia for cold-adapted species due to their microclimate features and thermal inertia. However, integrated research comparing active rock glaciers with surrounding landforms to outline their ecological peculiarities is still scarce… Our data show remarkable differences between stable slopes and unstable landforms as a whole, while few differences occur between active scree slopes and active rock glaciers: such landforms show similar soil features but different ground surface temperatures (lower on active rock glaciers) and different occurrence of cold-adapted species (more frequent/abundant on active rock glaciers)… The role of active rock glaciers as potential warm-stage refugia for cold-adapted species is supported by our data; however, at least in the European Alps, their role in this may be less important than that of debris-covered glaciers, which are able to host cold-adapted species even below the climatic tree line.”

Read more about the role of active rock glaciers as potential warm-stage refugia here:

Rock glaciers in the European Alps (source: M Barton / Flickr).
Rock glaciers in the European Alps (source: M Barton/Flickr).


Fluid-Ice Structure Interaction of the Drygalski Ice Tongue

From UTAS: “The Drygalski Ice Tongue (DIT) is the largest floating glacier in Antarctica, extending approximately 120km into McMurdo Sound, and exhibits a significant influence upon the prevailing northward current, as the ice draft (measurement of ice thickness below the waterline) of the majority of the DIT is greater than the depth of the observed well-mixed surface layer. This influence is difficult to characterize using conventional methods such as in-situ LADCP (Lowered Acoustic Doppler Current Profiler) measurements, vertically collected profiles or long-term moorings as these are generally relatively spatially sparse datasets. In order to better relate measurements across the entire region of influence of the DIT region, a set of Computational Fluid Dynamics simulations (uses numerical analysis to analyze fluid flows) were conducted using a generalized topography of a mid-span transect of the DIT… Numerical modeling of environmental flows around ice structures advances the knowledge of the fluid dynamics of the system in not only the region surrounding the DIT but also provides a clearer insight into fluid-ice structure interactions and heat flux in the system. This may lead to a better understanding of the long-term fate of floating glaciers.”

Learn more about fluid-ice structure interactions here:

Drygalski ice tonguet (source: cohnveno / Flickr).
Drygalski ice tonguet (source: cohnveno/Flickr).


Flood Early Warning Systems (EWSs) in Bhutan

From ICIMOD: “Bhutan experiences frequent hydrometeorological disasters. In terms of relative exposure to flood risk as a percentage of population, Bhutan ranks fourth highest in the Asia-Pacific region, with 1.7% of its total population exposed to flood risk. It is likely that climate change will increase the frequency and severity of flood disasters in Bhutan. Inequalities in society are often amplified at the times of disaster and people living in poverty, especially women, the elderly, and children, are particularly vulnerable to flood hazards. Timely and reliable flood forecasting and early warnings that consider the needs of both women and men can contribute to saving lives and property. Early warning systems (EWSs) that are people-centered, accurate, timely, and understandable to communities at risk and that recommend the appropriate action to be taken by vulnerable communities can save people more effectively. To improve the understanding of existing early warning systems (EWSs) in the region and their effectiveness, ICIMOD has conducted an assessment of flood EWS in four countries (Bangladesh, Bhutan, Nepal, and Pakistan) from a gendered perspective. The objective is to support the development of timely, reliable, and effective systems that can save lives and livelihoods.”

Read more about flood early warning systems in Bhutan here:

UNDP Bhutan GOLF Thorthormi lake workers (source: UNDP / Flickr).
UNDP Bhutan GOLF Thorthormi lake workers (source: UNDP/Flickr).

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