Tadpole Shrimp, Arctic Charr, and Glacial Retreat in Svalbard

Popular images of the Arctic often feature a polar bear with its white fur matching the surrounding sea ice or a narwhal with its tusk piercing the ocean waves. You are less likely to consider the Arctic tadpole shrimp, a tiny crustacean that is vitally important to many food webs in harsh Arctic environments. A recent study in the journal Boreal Environment Research examined the tadpole shrimp and its contribution to the diet of the small salmon-related Arctic charr in a glacial-fed river and lake in Svalbard, Norway.

Arctic tadpole shrimp are found in lakes across the Arctic, from Siberia to Iceland. The size of the shrimp population in a lake reflects the density of the charr population. In deeper lakes, where Arctic charr are prevalent, the shrimp are rare or not found at all, but in shallow lakes with few or no charr, the shrimp are widespread. In lakes where the two species coexist, the shrimp are a key source of food for the charr.

Photo of the Arctic tadpole shirmp
The Arctic tadpole shrimp (Source: Reidar Borgstrøm).

Though the connection between charr and tadpole shrimp populations has been established, no one had ever studied the charr’s diet in Arctic streams, many of which flow into lakes inhabited by both the tadpole shrimp and charr. This study set out to fill this gap by examining the summertime diet of riverine charr on Spitsbergen, the largest of the islands of the Svalbard archipelago.

The study focused on the streams that feed the shallow lake Straumsjøen on Spitsbergen and its outlet river. The streams that empty into the lake from the south and west discharge clear water, while water flowing from the northern stream fed by the glacier Geabreen is cold and cloudy because of glacial meltwater and silt.

Map of Straumsjøen
Svalbard with the location of Straumsjøen and its outlet river (Source: Borgstrøm et al.).

To analyze the diets of the charr, the authors captured fish from the the lake’s outlet stream by utilizing electrofishing, a fish surveying method that stuns a fish when it swims near an electrode-generated electric field. The researchers then killed the captured fish and analyzed the contents of their stomachs.

The results were surprising. Charr caught in the outlet river had tadpole shrimp in their stomaches. This discovery was unexpected because young tadpole shrimp are planktonic, meaning they drift in the water instead of swimming, which is why they were previously thought to be unable to inhabit running waters. In fact, this was the first time the tadpole shrimp had ever been recorded in running waters and as a part of a charr’s diet on Spitsbergen.

One possible explanation for the tadpole shrimp’s presence in the outlet river is that the shrimp simply drifted from lake Straumsjøen and ponds connected to the river, according to the authors. However, this possibility was considered unlikely given the significant number of tadpole shrimp found in the diet of riverine charr.

Photo of the outlet river.
A section of the outlet river from Straumsjøen (Source: Borgstrøm et al.).

The more likely explanation takes three factors into account, one of which is the glacier. First, the eggs and larva of the tadpole shrimp are adhesive and able to attach to rocks and other objects within the rivers. This trait would allow the shrimp to avoid being washed away down the river. Secondly, the presence of the tadpole shrimp in the rivers could signal low fish density. A lower fish density would allow the tadpole shrimp population to remain steady and still contribute to the charr diets.

The third factor is the retreat of the glacier Geabreen which feeds lake Straumsjøen and its outlet river. The glacier’s retreat has caused a subsequent decrease in the discharge of cold, silty meltwater into the lake. Thus, the presence of the tadpole shrimp in the Straumsjøen watercourse may be a result of the upstream retreat of the Geabreen, as resultant river conditions are now more conducive to tadpole shrimp, lead author Reidar Borgstrøm told GlacierHub.

The changing climate driving the retreat of the Geabreen glacier is also likely to impact river conditions and in turn tadpole shrimp populations. Under future climate change scenarios, the Arctic is projected to get warmer and wetter. Rising temperatures in Svalbard during the summer months, however, are unlikely to negatively impact the tadpole shrimp as populations of this widely distributed species in southern Norway, where summers are already fairly warm, have remained stable, Borgstrøm said.

Photo of Spitsbergen
A glacier on Spitsbergen, the island where the study took place (Source: Fins and Fluke/Twitter)

Increased rainfall in conjunction with increased glacial meltwater, on the other hand, could have a negative effect on the tadpole shrimp, as the heightened streamflow could potentially flush the tadpole shrimp from the river. These changing conditions may cause riverine tadpole shrimp populations to fall, which would in turn have a cascading effect on the Arctic charr who rely on the shrimp as a major source of food in the Straumsjøen watercourse.

Future studies in both Svalbard and other places across the Arctic would help scientists better understand how glacial retreat and climate change will impact the tadpole shrimp and other species.

Video of the Week: Listening to Glaciers Melt

Glaciers around the world are melting, all at different speeds. In this week’s Video of the Week, check out how scientists are using the sounds from melting Arctic glaciers to assess the speed of glacier melting.

The sounds are produced by air bubbles that become trapped when snow turns to ice over time. When the ice melts, the bubbles pop in the water producing a sound that can help show how fast a glacier is melting. By using acoustical recordings, scientists hope to improve our understanding of how sea levels may rise in the future. The video was published by the American Geophysical Union. In addition to this video, check out GlacierHub’s article on the paper behind the video.

Read more glacier news at GlacierHub:

Meet the Writers of GlacierHub, 2017/2018 Edition

Biggest Rat Eradication Project Ever Deemed A Success

Where Scientists Sleep: A History of Alpine Huts

Biggest Rat Eradication Project Ever Deemed A Success

On the heavily glacierized island of South Georgia, a British overseas territory in the southern Atlantic, rats have been completely eradicated. The island, once traversed in 1916 by polar explorer Ernest Shackleton during an ill-fated Antarctic expedition, was declared rodent-free on 8 May 2018 by the South Georgia Heritage Trust (SGHT), a Scottish-based organization which helps conserve indigenous species and the historical heritage of the island.

The rat eradication plan, which began in 2008, was developed and carried out by the SGHT’s Habitat Restoration Project and covered 108,723 hectares (1087 km2), making it the largest successful rodent eradication project ever, over eight times bigger than any previously completed undertaking.

Photo of the South Georgia Pipit
The South Georgia Pipit (Source: Ingo Arndt/SGHT).

Why rid the island of all of its rodents?

The story begins in the 18th century when rats were first introduced to South Georgia by ships hunting seals and whales in the nearby waters. The human introduction of rats proved disastrous for the island’s native bird species, specifically the South Georgia pipit and South Georgia pintail, which are found nowhere else in the world. The species evolved in an environment that lacked natural predators. The rats preyed upon the birds’ eggs and chicks along the island’s coastal areas, driving the species nearly to extinction. These coastal areas, devoid of trees, were the only viable habitat for the birds, which made their eggs and chicks in ground nests easy targets for the rats.

Glaciers also played an important role in the story of this project. Glaciers cover over 50 percent of the island due to its sub-Antarctic location and high elevation. Through a genetic analysis of the island’s rat population, the project found that the rats did not cross the glaciers, which served as natural barriers, preventing the rats from infesting rat-free areas, according to Dickie Hall, one of the directors of the project who spoke with GlacierHub about its success. With help from the glaciers, the SGHT could bait and poison the island’s rats in stages over the course of several years, safe in the knowledge that rodents from a neighboring part of the island would not be able to re-invade, according to Hall.

Photo of South Georgia glacier
A glacier on South Georgia (Source: Oliver Prince/SGHT).

However, the glaciers on South Georgia like most around the world are retreating due to climate change. When the glaciers retreated from the island’s coast, they provided a “local benefit to some species by increasing habitat areas,” Hall said. The retreating glaciers left wide flat beaches that became breeding grounds for penguins and seals, for example, which attracted the rats due to new food sources like eggs and carrion. The beaches also acted as bridges, allowing rats to infiltrate rat-free areas of the island once protected by the glaciers, Hall continued.  

The retreating glaciers also meant SGHT had to move fast to respond to the South Georgia rat population while the ice still separated South Georgia “into islands of habitat,” added Hall. Overall, he said, it was the presence of the glaciers dividing the rat populations that made the baiting project feasible.

The SGHT project’s field operations employed helicopters to drop poisoned bait across the island’s ice-free areas. Over the course of the project’s three phases, over 300 metric tons of bait were dropped.

Photo of Helicopter with poisoned bait flying over a glacier
Helicopter with poisoned bait flying over a glacier on South Georgia (Source: Tony Martin/SGHT).

The first of these operations began back in 2011 as a pilot phase that successfully eradicated the target area’s rats. Two additional field operations followed the pilot in 2013/14 and 2015/16 to eradicate the rest of the island’s rats. While early indicators for rat eradication appeared favorable, the SGHT waited two years before conducting a final surveying expedition and declaring South Georgia rat-free.

The expedition, dubbed “Team Rat,” searched for any remaining rats on the island over the course of six months. The team utilized chewsticks, tracking tunnels (rectangular boxes used to trap animals), and a team of skilled rodent detectors that included three dogs and their human handlers.

Throughout the six-month search for any remaining rats, the dogs walked close to 2,500 km and climbed an astounding distance equivalent to hiking Mt. Everest close to thirteen times. At the conclusion of the arduous survey by Team Rat, not one single rat was found left on the island. With the eradication of the rats complete, bird populations, most notably the South Georgia Pipit, have begun to recover across the island.  

Photo of rodent detection dogs and pengiuns
Project worker Miriam Ritchie and her rodent detection dogs Ahu and Willl at Macdonald Cove on March 08, 2018 (Source: Oliver Price/SGHT).

Alternatives besides complete rat eradication were also considered by SGHT, according to Hall. One potential option was to reduce and subsequently maintain the island’s rat population at a low level to limit their impact on bird populations and the environment. However, this option was ultimately not pursued. One of the reasons for this was because of the option’s high labor intensity. In addition, the island’s rapidly retreating glaciers made the island more interconnected than ever before, according to Hall, meaning control would become progressively more difficult as the glaciers continued to retreat and the rats continued to increase in other areas of the island.

For eradication to have the best chance for success, the SGHT had to act now before South Georgia’s remaining glaciers vanished. In the future, it will also be crucial to prevent a re-invasion of rats. Fortunately, South Georgia is one of the most remote places on Earth, so humans and ships are the sole way for invasive rats to be reintroduced. Even so, to prevent unintended reintroductions, Hall indicates that the government of South Georgia and South Sandwich Islands has already tested the use of rodent detector dogs and implemented stringent biosecurity policies regulating imports on to the island.

Overall, preventing a bird species from becoming extinct might not come to mind when one thinks of retreating glaciers. Nonetheless, the project serves as a reminder of our interconnected world and of the vulnerability of birds and all living things.

Roundup: Mt. Everest Climbing, Glacier Movie, and Plants

Everest Climbing Route at Risk from Climate Change

From The Washington Post: “As climbers begin to reach the summit of Mount Everest, some veterans are avoiding the Nepali side of the world’s highest peak because melting ice and crowds have made its famed Khumbu Icefall too dangerous… Several veteran climbers and well-respected Western climbing companies have moved their expeditions to the northern side of the mountain in Tibet in recent years, saying rising temperatures and inexperienced climbers have made the icefall more vulnerable. Research by the International Center for Integrated Mountain Development shows that the Khumbu glacier is retreating at an average of 65 feet per year, raising the risk of avalanche.”

Read more about the climbing route here.

Photo of the Khumbu Icefall
The Khumbu Icefall from the Mt. Everest base camp (Source: Mark Horrell/Creative Commons).


Movie at Cannes Shot on Glacier in Iceland

From Variety: “‘Arctic,’ a notably quiet and captivating slow-build adventure film, starring Mads Mikkelsen as a researcher-explorer who has crash-landed in the frozen wilderness, is the latest example of a genre we know in our bones, one that feels so familiar it’s almost comforting. It’s another solo-survival movie, one more tale of a shipwrecked soul that derives its spirit and design from the mythic fable of the form, ‘Robinson Crusoe.’ The challenge of watching a stranded man toil away on his own, of course, is that it seems, on the surface, to be inherently undramatic. That’s why nearly every one of these movies has had a buried hook, a way of turning a barren situation into compulsively watchable and suspenseful storytelling. “Robinson Crusoe” (the novel, published in 1719, and its various film versions) set the template by presenting its tale as one of human ingenuity — in essence, it prophesied the Industrial Revolution in the form of a stripped-down one-man show. “Cast Away” had Wilson the soccer ball and Tom Hanks’ plucky enterprise. “127 Hours” had James Franco, as a hiker trapped in a rocky wedge, nattering into his video camera. “All Is Lost,” set on a sailboat adrift at sea, had Robert Redford’s finely aging regret and his character’s technical instincts. “Robinson Crusoe” had Friday.”

Read more about the movie here.

Photo of lead actor Mads Mikkelsen
Lead actor Mads Mikkelsen (Source: Total Flim/Twitter).


Study Examines Plants Exposed Due to Glacial Retreat

From the Journal of Plant Research: “To examine carbon allocation, nitrogen acquisition and net production in nutrient-poor conditions, we examined allocation patterns among organs of shrub Alnus fruticosa at a young 80-year-old moraine in Kamchatka… Since the leaf mass isometrically scaled to root nodule mass, growth of each individual occurred at the leaves and root nodules in a coordinated manner. It is suggested that their isometric increase contributes to the increase in net production per plant for A. fruticosa in nutrient-poor conditions.”

Read more about the study here.

Photo of The Koryto Glacier in Kamchatka and the valley below the glacier
The Koryto Glacier in Kamchatka (top) and the valley below the glacier (bottom) (Source: Takahashi et al.).

Project Aims to Better Understand “Doomsday” Glacier

On April 30, 2018, the largest joint United States-United Kingdom Antarctic project since the 1940s was announced at the British Antarctic Survey in Cambridge. The International Thwaites Glacier Collaboration (ITGC) will focus on the Thwaites glacier of West Antarctica, one of the world’s largest and fastest melting glaciers.

The Thwaites has already contributed to 4 percent of observed global sea-level rise, but the rapid melting of the Thwaites is not scientists’ only concern. The glacier acts as a sort of plug, protecting the rest of the West Antarctic ice sheet from melting. But if the Thwaites were to collapse, most of the West Antarctic ice sheet would be destabilized, likely leading to its impending collapse. This so called “‘Doomsday”’ scenario would cause sea levels to rise 10 feet on average across the Earth.

Photo of the Thwaites Glacier from above
Aerial view of the Thwaites Glacier (Source: Earth Insitute/Twitter).

The ITGC, a $25 million, five-year collaboration between the U.S. National Science Foundation and UK Natural Environment Research Council, will include six scientific field studies with over 100 scientists using a number of different technologies and techniques to analyze the changes to the Thwaites and surrounding ocean.

Getting to the white expanses of the Thwaites is no easy task due to its remote location in Antarctica. In fact, only a handful of people have actually stood on the glacier. For this reason, most scientific research takes place at the more accessible national research stations, according to Jessica O’Reilly, an anthropologist at Indiana University who studies the Antarctic. “Deep field” projects like the ITGC are much rarer because of logistical challenges like coordinating multiple flights to remote areas in erratic weather and the sheer cost of such endeavors, she added.    

This threshold system is further unique to West Antarctica, according to O’Reilly, because it is a marine ice sheet, meaning its grounding line (where ice meets the underlying bed) is under water instead of on land. “Therefore, not only does air surface temperature interact with the ice sheet, but the warming ocean underneath it can also destabilize it,” she said. This distinction makes the Thwaites and rest of the West Antarctic extremely vulnerable to melting, a reality that has inspired a geoengineering proposal to build underwater walls at the grounding line of glaciers like the Thwaites to slow down melting and possibly prevent collapse.

NERC figure depicting the project's different missions
NERC figure depicting the project’s different missions (Source: NERC).

The U.S.-UK research endeavor and its six-field missions will assess just how at risk the Thwaites is to a catastrophic collapse. One of these missions will be led by Penn State Glaciologist Sridhar Anandakrishnan, who spoke to GlacierHub about the project. In Antarctica, Anandakrishnan and his team will be conducting geophysical surveys to characterize the base of the glacier. The surface where ice meets bedrock affects the way the Thwaites flows and is important for projecting how the glacier will retreat. Presently, according to Anandakrishnan, there is a need for improved information on this surface at the Thwaites. “Is it soft or hard? Is it smooth or rough? And so on,” he said.

To obtain this information, Anandakrishnan’s team will use both seismic and radar techniques. From a seismic approach, small explosives will be set off right below the glacier’s surface. The team will then listen for the explosion’s echo from the bottom of the glacier. Based on the time it takes for the echo to return and its strength, the team will be able to better understand the surface where glacial ice meets bedrock.

The radar approach involves a similar process where the team will emit a radar pulse, detect the reflected pulse, and interpret the time and amplitude of the returned pulse for information such as ice thickness, according to Anandakrishnan.

Thwaites Glacier from above
The seemingly endless expanses of the Thwaites Glacier (Source: Hannah Hickey/Twitter).

In addition to this field mission, the five others will examine the Thwaites from different focuses. These include measuring the glacier’s melting at its grounding line; measuring ocean circulation and glacial thinning underneath the floating portion of the glacier using autonomous submersibles; sampling bedrock beneath the glacier to better understand its past retreats and recoveries; analyzing the glacier’s margins to study what controls its width and speed; and examining sediments deposited in the ocean near the glacier to reconstruct past environmental changes and the Thwaites’s response to these changes.

Two other non-field missions will utilize computer models and simulations to assess processes that could cause the rapid retreat and collapse of the glacier and to improve projections on its future behavior and contribution to sea level rise.  

Photo of Boaty McBoatface
The autonomous submersible Boaty McBoatface which will participate in the project (Gizmodo/Twitter).

According to Anandakrishnan, these missions fall in line with one of the main goals of the ITGC: to better understand the Thwaites by improving modeling and projections of the future state of the glacier. Even without a collapse, the Thwaites could contribute up to one meter of sea-level rise over the next century, a change that would have devastating effects on the world’s coastal communities.

If the goals of the project can be accomplished, “we can better estimate what this glacier would do under various future climate scenarios,” Anandakrishnan said. Overall, the U.S.-UK Antarctic project will be a big step forward for humanity’s understanding of a glacier that could have a profound impact on society if it were to collapse.   


Photo Friday: Traversing the Chilean Andes by Bicycle

This Photo Friday, traverse the glaciers of the Chilean Andes with Marcos Cole, a Chilean geographer and mountain guide. Cole, as part of his Glaciers by Bicycle project, is currently traveling by bicycle from the Altiplano region in the north of Chile all the way to Tierra del Fuego in the far south.

The project has three objectives, the first of which is to create a photographic database of Chilean glaciers for future studies on glacial retreat and global change. Second, by traveling by bicycle, Cole hopes to demonstrate the importance of the bicycle in the fight against climate change. Lastly, Cole wants to highlight the importance of glaciers for society and ecosystems through the creation of a documentary of his travels.

Take a sneak peek of some of his personal photos.

Photo of Marcos Cole in front of the Sierra Velluda volcano
Marcos Cole and his bicycle near the east face of the Sierra Velluda volcano in the Bío Bío region of Chile taken in December 2017 (Source: Glaciers by Bicycle).
Photo of the glaciers of the Osorno Volcano
The glaciers of the Osorno Volcano on the shores of Llanquihue Lake in the Los Lagos region of Chile taken in February 2018 (Source: Glaciers by Bicycle).
Photo of the Queulat Hanging Glacier
The Queulat Hanging Glacier located in the Aysén Region of southern Chile taken in March 2018 (Source: Glaciers by Bicycle).
Photo of Leones Glacier
The Leones Glacier of the northern Patagonia ice-field taken in March 2018 (Source: Glaciers by Bicycle).
Photo of the Calluqueo glacier
The Calluqueo glacier on the slopes of Monte San Lorenzo in Cochrane, Chile taken in March 2018 (Source: Glaciers by Bicycle).

Video of the Week: Fly Over the Chugach Mountains and Knik Glacier

This week, fly above Alaska’s Chugach Mountains and Knik Glacier in a video shot by Chris Reynolds piloting a motorized paraglider. The glacier, just 50 miles from Anchorage, is one of the largest in southern Alaska at over 100,00 acres and originates near the peak of the 13,000-foot Mt. Marcus Baker.

Read more glacier news at GlacierHub:

Communities in Nepal Expand to Risk Areas, Despite Hazards

Photo Friday: A Visit to Sajama, Bolivia

A New Low for the Atlantic Meridional Overturning Circulation


Climate Change in the High Arctic: Lake Hazen’s Response

High above the Arctic Circle, far from the footprint of human civilization, a significant indication of human-induced climate change has manifested in Lake Hazen, the largest lake by volume north of the Arctic Circle. The lake and surrounding glacial environment are experiencing rapid change as the climate warms, ice cover declines, and glaciers retreat. A recent study in Nature Communications examines these physical drivers and their impacts on the lake’s ecological composition and the physiological condition of its only fish species, the Arctic Char. These changes, unprecedented in 300 years, have serious ramifications for local indigenous populations who rely on the lake’s ecosystem services.

Map of Lake Hazen watershed
Map outlining the Lake Hazen watershed and changes in surrounding glacier surface temperatures from 2000 to 2012 (Source: Lehnherr et al.).

In northern Ellesmere Island, the farthest north of the islands that compose the Canadian Arctic Archipelago, summer air temperatures increased by 1 degree Celsius during the 2001 to 2012 period in comparison to the period 1986 to 2000. Climate model simulations suggest temperatures are expected to increase 3.2 degrees Celsius by 2100. These changes have the potential to dramatically alter local ecosystems.

The study’s research team, which included experienced Arctic scientists from a diverse set of backgrounds, grew over time, according to Igor Lehnherr, who spoke with GlacierHub. From a scientific standpoint, the team knew that glacial masses were shrinking in other parts of the Arctic, along with summer lake ice cover. From this basis, according to Lehnherr, it was ”a matter of bringing everyone on board with all the different expertise required to quantify each of these various aspects.”

The study’s authors note that few previous studies have evaluated ecosystem-scale changes to climate change in inland watersheds. Lehnherr cited the need for a multidisciplinary team and baseline data to “quantify how much the system has changed and what drivers are responsible for ecological change” as challenges to study.

Photo of Eureka Sound on Ellesmere Island
Eureka Sound on Ellesmere Island (Source: Stuart Rankin/Creative Commons).

The researchers benefitted from over 50 years of scientific research on Lake Hazen, helping this recent study fill part of this knowledge gap by analyzing how the lake’s ecosystem has responded to climate change. The study does this through four distinct, yet interconnected focuses: watershed warming and declining lake ice cover, hydrological changes within the watershed, recent changes in the paleo-lake record, and ecological shifts in the lake itself.

Watershed Warming and Declining Lake Ice Cover

From 2000 to 2012, summer air temperatures in the Lake Hazen watershed rose by 2.6 degrees Celsius, with most of the rise occurring after 2007. These higher air temperatures, in turn, warmed the soil. Spring-time soil temperatures were 4 degrees Celsius higher from 2007 to 2012 than they were from 1994 to 2006. The lake warms particularly in late spring, when it is still covered by ice, and in early summer, when ice cover finally breaks up. Overall, the lake’s warming trend is causing ice to melt earlier in the summer and freeze later in the fall. This is in addition to an increase in ice-free area by 3 km2 per year since 2000, which was found to be related to August lake surface temperatures.

Hydrological Changes within the Watershed

Glaciers within the Lake Hazen watershed are the main hydrological driver. Because of warming temperatures, these glaciers are experiencing mass-balance losses. Positive feedback loops play a role in this loss, as high surface temperatures melt ice, subsequently decreasing reflectivity, which allows the surrounding surface to absorb more solar radiation, speeding up melting.

Figure detailing trends in lake surface temperatures, onset dates for ice melt and freeze up, and ice cover.
Figure detailing trends in lake surface temperatures, onset dates for ice melt and freeze up, and ice cover (Source: Lehnherr et al.).

Mean rates of annual glacial runoff have increased significantly in recent years. This increase has raised water levels in Lake Hazen by almost a meter since 2007. Finally, the large increase in glacial runoff into Lake Hazen has lowered the time that water stays in the lake (before leaving by the lake’s one outflow stream) from a historical average of 89 years to 25 years today.

Recent Changes in the Paleo-Lake Record

The increase in glacial runoff entering Lake Hazen has driven sediment accumulation rates to levels eight times higher than a 1948 baseline period. Most runoff is deposited by glacier-fed rivers that empty into the lake, leading to the increased mixing and oxygenation of the lake’s once stable and anoxic bottom waters.

More sediment deposition has also given rise to increased levels of anthropogenic contaminants, such as mercury and pesticides, in lake sediments. In addition, organic carbon accumulation rates in the lake have increased by an astonishing 1000 percent, much higher than the 50 percent increase in most North American boreal lakes.

Ecological Shifts

To assess the impact of the lake’s changes outlined above on its ecology, the authors used micro-fossil counts of algae. Before widespread warming (prior to 1890), when the lake was covered with ice almost year-round, algal fossils were rare. However, after warming (post 1890), when more areas of the lake became ice-free, nearshore algal species boomed.

After remaining relatively stable for much of the 20th century, the lake’s ecological composition changed in the late 1980s when planktonic species succeeded benthic species. This change was driven by a longer ice-free period where the deep waters of the lake were exposed to light for more months each year.

Photo of Lake Hazen
Lake Hazen (Source: Igor Lehnherr).

Lake Hazen’s one fish species, the Arctic Char, has also been negatively impacted by climate warming. Lehnherr notes that the team might have expected ice-free summers to increase the lake’s primary productivity, subsequently increasing biomass and leading to healthier and thriving Char populations. However, this has yet to occur; instead, amplified lake turbidity due to the raised levels of glacial river discharge has hindered the ability of the visually reliant Char to feed on midges and other Char, harming their physiological condition.


These changes have negative effects on the lake’s ecology and also on indigenous communities that inhabit the area. These communities rely on the lake as a source of food in an otherwise desolate region. While the future of High Arctic ecosystems is far from certain, Lehnherr points to the need for more multidisciplinary studies that encompass entire watersheds as a key to the better assessment of climate change impacts.

Roundup: Project BlackIce, Larvae, and Nature Study Retraction

Project BlackIce Examines Microbes and Glacial Albedo

From Project BlackIce: “Algae can protect themselves before damaging UV-radiation by darker pigmentation which results in a darkening of the surface which is increasing the availability of liquid water, hence again the growth of microbial communities. This biologically induced impact on albedo is called ‘bioalbedo’ which has never been taken into account in climate models. So far we have most information on bioalbedo on arctic glaciers which is quite a shame that literally nothing is known about alpine glaciers. The aim of this interdisciplinary study is a quantification and qualification of organic and inorganic particles on an alpine glacier (Jamtalferner).”

Learn more about Project BlackIce here.

Photo of Project BlackIce logo.
The Project BlackIce logo (Source: Project BlackIce).

Patterns in Larvae Size in Glacial Streams

From Schütz & Füreder: “Glacially influenced alpine streams are characterized by year-round harsh environmental conditions. Only a few, highly adapted benthic insects, mainly chironomid larvae (genus Diamesa) live in these extreme conditions. Although several studies have shown patterns in ecosystem structure and function in alpine streams, cause–effect relationships of abiotic components on aquatic insects’ life strategies are still unknown. Sampling was performed at Schlatenbach, a river draining the Schlatenkees (Hohe Tauern NP, Austria)… This is the first study to show that harsh conditions in these environments (low temperatures, high turbidity and flow dynamics) may exclude many taxa, but favor other, highly adapted species, when their essential needs (food quality and quantity) are guaranteed.”

Learn more about the study here.

Image of the Diamesa cinerella larva
The Diamesa cinerella larva. Numbers represent the sites where measurements were taken (Source: Schütz & Füreder).


Nature Study on Asian Glaciers Retracted

From Nature: “In this article, I estimated net glacial melt volumes on the river-basin scale from long-term precipitation and temperature records (1951–2007), taking into account the various mass contributions from avalanching, sublimation, snow drifting and so on… I estimated the second meltwater component (the additional contribution from glacier losses) as −0.35 to −0.40 metres water-equivalent per decade based on a global compilation of long-term mass-balance observations (from table 2 in ref. 32 of the Article). In this table, losses are described as ‘decadal averages (millimetres water equivalent)’ but the units are actually intended to be decadally averaged annual values. Hence, the loss components of total meltwater that I used in my calculations are too small and the summed meltwater volumes reported here should be larger. Asia’s glaciers are thus regionally a more important buffer against drought than I first stated, strengthening some of the conclusions of this study but also altering others. I am therefore retracting this article.”

Learn more about the retraction here.

A figure from the retracted study.
A figure from the retracted study (Source: Nature/Twitter).



The Glacier Law Conundrum: Protecting Glaciers or Limiting Hazard Response and Adaptation?

The environmental and socioeconomic benefits of the world’s glaciers, from their role in water storage to their influence in tourism, have led to the development of national laws to protect glacial environments from activities like mining that could adversely alter them. While legal protections aim to safeguard glaciers and the value they generate, the laws often fail to account for the actions necessary to mitigate glacial hazards or adapt to climate change. A recently published study in Ambio examined glacier protection laws in Argentina and Chile in an effort to explore how laws could better address interventions in rapidly changing glacial areas.

Figure of rapid growth of a glacial lake
Figure detailing the rapid growth of a glacial-dammed lake, highlighting the need for a quick mitigation response to glacial hazards (Source: Iribarren et al. 2018).

The study was part of the Newton Picarte project on Glacial Hazards in Chile, a partnership between Universidad Austral in Chile and Aberystwyth University in the United Kingdom. Its goal, according to author Pablo Iribarren, a glaciology lecturer at Universidad Austral, was to emphasize that glaciers not only provide environmental and socioeconomic benefits but also pose a threat to mountain communities. In addition, Iribarren told GlacierHub that “…this duality must be considered by Glacier Protection Laws (GPLs) to better face challenges associated with a rapidly changing cryosphere.”

It might seem impossible to protect glaciers, except by reducing greenhouse gas concentrations in the atmosphere. But there are other concrete steps that countries can take, particularly in relation to mining. GPLs are a relatively new phenomenon intended to preserve glaciers and their surrounding environments from commercial endeavors. Argentina was the first country to ratify a GPL in 2010. Chile and Kyrgyzstan have also developed GPLs, although these laws have yet to be ratified, due largely to the power of the extractive lobby. The opposition to GPLs from the mining industry and even the government is robust because of the economic benefits of natural resource extraction. For example, in the central Chilean Andes 55.1 billion dollars were generated from 2004 to 2011 and over 60,000 people were employed by the industry.

Photo of the entrance to Pascua Lama mine
The entrance to the controversial Pascua Lama mine. Barrick Gold is the Canadian mining company behind the project (Source: infogatecl/Twitter).

Mining and other natural resources extraction activities on and near glaciers in many cases destroy ice or cover it with debris and contaminate water resources. Chiles’s unresolved GPL, for instance, stemmed from a mining project known as Pascua Lama developed by Barrick Gold, a Canadian mining company that proposed the removal of glacial ice for mining purposes. However, despite intending to protect glaciers from destruction or alteration, GPLs can also inhibit the mitigation of glacial hazards and climate change adaptation by limiting intervention in glacial environments.

Glacial hazards are primarily caused by three sometimes concurrent processes: glacial advance, glacial blockage of mountain streams, and the growth and subsequent failure of glacial-dammed lakes. In the case of advancing glaciers, their leading fronts can become stranded, blocking streams and creating lakes. These glacial dams are then particularly vulnerable to melting. A well-known glacial disaster occurred through this mechanism in the Argentinian Andes in 1934, when an ice-dam blocking a stream failed. The resultant flood inundated a valley below, killing 20 people. Conversely, retreating glaciers often leave in their wake glacial lakes, some of which can be very large in volume. When the volumes of these lakes increase or when waves from glacial calving strike the dam, damaging outburst floods can occur.

Photo of the draining of a glacial lake
The draining a glacial lake in the Himalayas to reduce the risk of an outburst flood (Source: Renaud Meyer/Twitter).

To reduce the risks posed by glacial hazards, different strategies can be employed. One strategy for an ice-dammed lake is the modification of the ice dam itself through reinforcement methods like increasing its impermeability. Another strategy involves the actual excavation or blasting of ice to prevent glacial advance or to preemptively drain an ice-dammed lake. In another form of intervention, local communities near glaciers might utilize glacial lakes as a water reservoir in response to reduced water availability due to climate change or reduce the risk of outburst floods by lowering lake levels.

However, conflict arises between these glacial interventions and GPLs because interventions usually involve the modification of the glacial environment. Under Argentina’s GPL Article 6, activities that modify a glacier’s natural condition or result in the destruction or movement of glacial ice are prohibited. Section 6b continues by prohibiting the construction of infrastructure on or near a glacier, although it does allow infrastructure for scientific purposes or to prevent risks.

Glacial hazard mitigation and climate change adaptation would fall under this article, but any proposed intervention would be subject to an Environmental Impact Statement (EIS), according to Article 7 of the GPL. Thus, the authors presume that “the most likely scenario for handling a hazard would be to conduct an EIS, yet this procedure may take months or even years.” During this possibly time-consuming process, a hazard “could put lives and infrastructure in danger.” For another view on this issue, GlacierHub spoke to Jorge Daniel Taillant, executive director of the Center for Human Rights and Environment, and author of “Glaciers: The Politics of Ice,” who finds it unlikely that preventive action against a potential glacial hazard would be delayed by a GPL and an accompanying EIS.

Why the disconnect between Argentina’s GPL and glacial interventions for hazard mitigation and climate change adaptation purposes? For Iribarren, it’s a result of the GPL being developed in response to conflict between mining and local communities fighting to protect their water supplies. Glacial hazards were simply ignored in the midst of a seemingly existential fight between international mining conglomerates and local people.

Photos of mine waste on a glacier and a damaged road that was built on top of a glacier
Photo A shows the mine waste that was dumped on top of a glacier in Kyrgyzstan. Photo B shows a road built over a glacier in Chile which was damaged when the ice beneath it crept forward (Source: Iribarren et al. 2018).

The omission of glacial hazards and climate change adaptation during the development of GPLs means intervention into the glacial environment could possibly be impeded or even prohibited altogether. To improve upon this current intersection, the authors argue that GPLs should include allowances for glacial interventions that protect lives or infrastructure. They further argue that the process to authorize intervention should be sped up so that hazards are addressed in a timely manner, reducing the possibility of disaster. Finally, they propose that GPLs should clearly designate the government institutions responsible for glacial interventions.

While these proposals would likely help to improve GPLs, challenges would still remain. The biggest of these, according to Iribarren, is the possibility that GPLs that allow for easier glacial interventions could be used as a loophole for parties to intervene in glacial environments for strictly economic purposes like mining.

With Argentina’s GPL, the only one of its kind enacted worldwide, future research is undoubtedly needed to truly assess the conflicts these laws potentially pose. A first step in this process, Iribarren believes, is to study how other glacial countries like Peru or Switzerland have balanced “conflicts between economic interests and the protection of the cryosphere and surrounding landscapes.”

Future Sea-Level Rise and the Paris Agreement

The signing of the Paris Agreement in December 2015 signaled the world’s renewed focus on limiting global temperature rise to below 2 degrees Celsius, with a goal to lessen the adverse impacts of climate change. However, one of these impacts, sea-level rise, is already occurring and will continue long after emissions and temperatures stabilize. In other words, policies and decisions made now will set sea-level rise on a course to higher or lower levels. To better assess these effects, a recent paper published in Nature Communications examined the implications of the Paris Agreement’s goals on global sea levels up until the year 2300.

Photo of the Cop 21 logo
Logo for the UNFCC’s COP 21 where the Paris Agreement was signed (Roberto Della Seta/Twitter).

If we are to achieve the 2 degree Celsius goal of the Paris agreement, global greenhouse gas (GHG) emissions must peak and subsequently decline in the near future. This decline would coincide with the removal of emissions already in the atmosphere, through natural sinks, carbon capture and storage technologies, or both; ultimately leading to global net-zero GHG emissions sometime between 2050 and 2100. Most previous studies examining sea-level rise under different climate change scenarios only looked forward to 2100, and though a few extended farther into the future, none had yet to consider the implications of meeting the aims of the Paris Agreement.

The goal of this study was to fill this gap and assess the legacy of the Paris Agreement on sea level rise beyond the 21st century, author Alexander Nauels told GlacierHub. Another important motivation for the study was to investigate the effect of delayed climate mitigation action on future sea-level rise, he added.

Sea-level rise due to climate change is driven by several elements, including the thermal expansion of the oceans as they warm, the retreat of mountain glaciers, and the mass loss of ice sheets in Antarctica and Greenland. These elements react on different timescales to increasing temperatures ranging from hundreds (shallow water thermal expansion and glaciers) to thousands (major ice sheets) of years. Thus, emissions today will lock in future sea-level rise well into the future.

Photo of the Drang-Drung Glacier
Drang-Drung Glacier in Northern India. Mountain glaciers like it are one of the elements responsible for sea-level rise analyzed in this study (Source:sandeepachetan/Creative Commons).

To explore the relationship between the provisions of the Paris Agreement and sea-level rise, the study utilized a carbon cycle and climate model composite, together with a sea-level model. These models were driven by fossil fuel and industry emission scenarios that meet the Paris Agreement’s goal of limiting temperature rise to 2° C. These scenarios resemble the IPCC’s Representative Concentration Pathways (RCP) 2.6 scenario where emissions peak by 2020 and then decline thereafter. The emissions in these scenarios were limited to fossil fuels and industry because as Nauels states they are, “…by far the most important emission share when it comes to global decarbonistion.”

The scenarios chosen met either the net-zero GHG emissions goal of the Paris Agreement, seeing a gradual temperature decline over time due to GHG removal by carbon sinks, or a net-zero CO2 goal that would only limit temperature rise to 2° C. Why the two different scenario groups? Joeri Rogelj, another author of the study, told GlacierHub that they wanted to be able to distinguish between scenarios that only stabilize warming, partially meeting the Paris Agreement’s targets (net-zero CO2) and ones that fully comply with the Paris Agreement’s targets (net-zero GHG). This distinction enabled the authors to analyze the effect that delayed or insufficient mitigation action would have on sea-level rise.

Aerial Photo of Antartica
Aerial view of Antartica. The Antartic ice sheet is one of the elements responsible for sea-level rise analyzed in this study (Source: Pylyp Koszorús/Twitter).

There was a stark difference between the more stringent requirements of the Paris Agreement, slowly decreasing temperature through carbon sinks and action that would only stop temperature rise at 2° C. Under net-zero GHG scenarios, median sea-level rise was 73-123 cm, while under net-zero CO2 scenarios the median rise was a much higher level at 116-164 cm. Sea-level rise also continues through 2300 in all scenarios, emphasizing the need for immediate mitigation action, although, the rate begins to slow soon after emissions peak at 0.06-0.7 cm and 0.33-0.49 cm per year for the net-zero GHG and net-zero CO2 scenarios, respectively. Ominously, under net-zero CO2 scenarios, results showed that the possibility of sea-level rise of up to 5 m by 2300 was within the 90% confidence interval.

Figure of the sea-level rise response for partially meeting the Paris Agreement
Sea level rise response from the four contributors analyzed when the Paris Agreement’s goals are partially met (net-zero CO2) (Source: Mengel et al. 2018).

What happens if humanity only stabilizes temperatures instead of meeting the goals of the Paris Agreement?  When the authors compared the net-zero GHG and net-zero CO2 scenario groups, they found that median sea-level rise was 40 cm higher for the net-zero CO2 scenario. Another relevant factor for 2300 sea-level rise is the timing of the emissions peak. If the peak in global emissions is delayed by five years, an additional 20 cm of rise was found to occur in 2300 and when based on the 95th percentile the rise is an additional 1 m.

There is a good chance that global temperatures will increase by more than 1.5° C at least temporarily, with a 2017 study putting the chances of staying below a higher threshold of 2° C at 5%. The authors assessed this possible ‘temperature overshoot’ and found for every 10-year period where temperature rise is greater than 1.5° C a 4 cm increase in median sea-levels is expected. Overall, if global temperatures top 1.5° C no scenario showed median sea-level rise less than 1.2 m by 2300.

Figure of the sea-level rise response to fully meeting the Paris Agreement
Sea level rise response from the four contributors analyzed when the Paris Agreement’s goals are met in full (net-zero GHG) (Source: Mengel et al. 2018).

Lastly, the authors examined the connections between sea-level rise and the Paris Agreement’s Nationally Determined Contributions (NDC), the emission reduction goals of individual countries. If implemented in full, the NDCs would lead to a median sea-level rise between 1.45 and 1.64 meters under the net-zero CO2 scenarios and a median sea-level between 1.05 and 1.23 meters under the net-zero GHG scenarios. 95th percentile estimates for the NDCs were even more dramatic, with net-zero CO2 and net-zero GHG sea-level rises between 4.1 to 4.8 m and 2.3 to 3 m respectively.

Further research is needed to develop more precise estimates of sea-level rise into the future, according to Rogelj. He proposes several concrete steps inculding better continuous observations and improved model development for Antarctic ice sheet instabilities and Greenland ice discharge, both of which contributed the most to this study’s uncertainty ranges.

The findings of this study point to continued sea-level rise up until 2300, even if global GHG emissions reach net-zero levels. However, the authors note that high-end scenarios “can be halved through early and stringent emission reductions,” highlighting the urgent need for fast action on climate change from individuals all the way up to the world’s biggest countries.

Irrigation a Potential Driver of Glacial Advance in Asia

Glaciers in the High Mountains of Asia (HMA), like most mountain glaciers around the world, are retreating due to climate change. However, in the Karakoram mountains of northwest HMA, glaciers have remained stable, and in some cases, have actually advanced. A recently published study in Geophysical Research Letters delved into one of the potential drivers behind this climatic irregularity, irrigation.

The idea that irrigation, a human-induced change to the environment for agricultural production, could regionally counteract climate change, another human-driven change, might seem a bit far-fetched. And to Remco J. de Kok, Obbe A. Tuinenburg, and Walter W. Immerzeel, three of the authors of the study who spoke with GlacierHub, it did at first start out as a wild idea. Nevertheless, previous studies, including Tuineburg’s own Ph.D. thesis, found that evaporation from irrigation in India was being transported by atmospheric winds to Himalayan areas where it fell as snow or rain, likely contributing to the increased glacial mass observed.

Diagram detailing how irrigation drivers glacial advances
How the presence of irrigation impacts local climate and glaciers (Source: Remco de Kok/Twitter).

The most famous of the advancing glacier areas is the Karakoram anomaly, first coined in 2005 by Ken Hewitt. According to Immerzeel, the term gained traction in subsequent remote sensing studies that partly confirmed the anomaly. As it turned out, the Karakoram range was not the only region with stable or advancing glaciers. Studies published in 2013 and 2017 also found positive mass balances in the Pamirs and the Kunlun Shan mountains northeast of the Karakorams.

Prior research pointed to atmospheric circulation patterns and a particularly seasonal pattern (precipitation was concentrated in winter). These studies were conducted across a large spatial scale, and therefore their proposed mechanisms should support stable and advancing glaciers uniformly across the region. Yet, the glaciers just south of Karakoram show some of the highest glacial melt rates in the region, notes de Kok, while at the same time glaciers in the Kunlun Shan region northeast of Karakoram exhibit positive mass balances. These differences in a relatively small geographical area led the authors to consider two hypotheses: either the glaciers are responding differently to similar climatic changes or that the glaciers are experiencing different climatic changes.

To assess these hypotheses, the authors selected China’s Tarim basin. According to de Kok, “It is adjacent to the areas of largest glacier growth and has some of the biggest increases in irrigation.” Next, the authors needed to assess whether recent irrigation increases in the basin were impacting neighboring mountain climates in a way that would be conducive to glacial growth.

Satellite image of the Tarim Basin
Satellite image of the Tarim Basin. The green to the southwest are the new irrigation areas potentially driving glacial advances (Source: Stuart Rankin/Creative Commons).

The authors utilized a regional climate model known as the Weather Research and Forecasting model, or WRF for short. The model was run under two scenarios: a historical or stagnant scenario and a recent change scenario. The historical scenario represented the difference between model runs with modern irrigation and no irrigation, along with atmospheric greenhouse gas concentrations (GHG) held at 1900 levels. On the other hand, the recent change scenario represented the intensification of irrigation over the period 2000 to 2010 and a concurrent increase in GHG concentrations.

By applying these two scenarios, the authors were able to more accurately depict climatic changes and evaluate whether the impact of irrigation is significant in comparison to climate change. The authors were then able to compare the two to see if either had a dominant influence on the regional climate.

After running the models, the first apparent impacts of irrigation were an increase in evapotranspiration, a decrease in summer daytime temperatures, and an increase in atmospheric moisture directly over the basin.

Photo of Muztagh Ata
Muztagh Ata, a mountain of over 24,000 feet in the western Kunlun Shan (Source: dreamX/Creative Commons).

Then things got interesting.

The model runs showed increased summer snowfall in Kunlun Shan, Pamir, and northeast Tibet. These increases were largest for the historical scenario with 1900 GHG levels and modern irrigation, showing that the increase was primarily caused by irrigation, not GHG. The authors also analyzed changes in net radiation, the difference between incoming solar and outgoing terrestrial radiation. Across most of HMA, net radiation increased; conversely, in Kunlun Shan, net radiation decreased. This decrease is a result of a decrease in incoming solar radiation due to increased cloud cover and the increase in snow cover, which has a high albedo.

Map showing the changes to snowfall and net radiation
Changes to snowfall and net radiation in the Tarim basin region (Source: de Kok et al.).

The decrease in net radiation was found to counteract climate change’s enhanced greenhouse effect. Strikingly, when GHG were raised to current levels and irrigation was held at zero, the model results revealed an increase in net solar radiation across the entire region, signaling that irrigation is the principal reason for negative net radiation in Kunlun Shan.

While it was clear that increases in irrigation are leading to favorable conditions for glacier growth, where was this increased moisture coming from?

Model results pointed to the hypothesized Tarim basin as the main source of the increased moisture in the Kunlun Shan. The authors were able to corroborate this by conducting two model runs for the Tarim basin, one with no irrigation and one modern irrigation, while the rest of the region was held at modern levels. These runs revealed an increase in snowfall and a decrease in net radiation only when the Tarim basin had modern irrigation, confirming its influence.

Map of moisture source for summer snowfall in the Kunlun Shan
Map detailing the moisture source areas for Kunlun Shan summer snowfall (Source: de Kok et al.).

The irrigation of the Tarim basin is creating an advantageous environment for glacial growth, but the study is unable to attribute just how much this mechanism is contributing to the positive mass balance of the Kunlun Shan, a topic that will be the focus of future research, according to de Kok.

There’s also the question of sustainability for the recent increase in irrigation in the region as groundwater becomes more and more stressed and adverse ecological impacts in the otherwise arid Tarim basin take hold. A future reduction in irrigation could be bad news for glaciers, as the authors note it might “mean that the anomalous glacier mass balance in Kunlun Shan is of temporary nature.” Nonetheless, in a world where melting glaciers have become the new norm, stable glaciers, even if fleeting, are a welcomed respite.