In this week’s Video of the Week, check out the sport of Kok Boru, or goat polo, at the World Nomad Games held in Kyrgyzstan. The games were initiated by the Kyrgyzstan government in 2012 to help revive and preserve the culture of nomadic civilization. The first event took place in 2014 in Cholpon-Ata in the Issyk-Kul province of Kyrgyzstan. This year’s games took place September 3 to 8 in Cholpon-Ata with over 3,000 athletes from 77 countries participating. In this video, athletes compete in Kok Boru, where the aim is to get a goat or calf carcass into a goal.
This summer’s drought in Switzerland has been particularly harsh with the Swiss Weather Service declaring the months of July and August the driest since 1921. This severe water shortage has hit farmers hard in the heavily glacierized Alps, especially those with herds of cattle. In the highlands of the Canton of Vaud in western Switzerland, each head of cattle requires an astonishing 150 liters of water a day to subsist. To help the farmers and their cows struggling in the record dry conditions, the Swiss Army has been airlifting water by helicopter to these farms in terrain that is too difficult to reach by truck. Check out the photos below of the water airlifts in action.
Few areas of the planet have been more affected by climate change than the mountain cryosphere, where negative impacts like glacier recession far exceed any positives like short-term increases in glacial runoff. These adverse changes make highland environments ideal for examining the policy concept of Loss and Damage (L&D), which deals with the impact of climate change on resources and livelihoods that cannot be offset by adaptation. A recent study in Regional Environmental Change analyzes L&D in the mountain cryosphere by extracting examples from existing literature on the subject and developing a conceptual approach to support future research to address the subject.
L&D has become an important issue within the international climate policy realm in recent years. In the mountain cryosphere, the effects of climate change and the resultant L&D are directly evident. However, despite the visibility of these changes, research on L&D has rarely focused on these mountain environments, says the study’s lead author Christian Huggel, who spoke with GlacierHub about his paper.
The dearth of research presented a unique opportunity for Huggel and his team to analyze L&D in the mountain cryosphere, to provide information to policymakers, and to create a framework for future research.
L&D work within the United Nations Framework Convention on Climate Change (UNFCCC) first emerged around the impacts of sea-level rise on Small Island Developing States in the early 1990s, gaining further traction at the UNFCCC’s COP19 in Warsaw, where the Warsaw Mechanism for Loss and Damage associated with Climate Change Impacts was established. Then in 2015, at the landmark COP21 in Paris, the Paris Agreement’s Article 8 was dedicated to L&D. Although this article acknowledges the importance of L&D, it also states that it “does not involve or provide a basis for any liability or compensation,” which is a serious limit to concrete action.
Despite the attention to L&D in international climate negotiations, significant controversy still surrounds the issue. Most of this controversy centers on the historical responsibility and potential liability of the developed countries for climate change impacts, with developing countries arguing for compensation, risk management, and insurance from the developed world.
Huggel told GlacierHub, “As the first systematic study of L&D in the Mountain Cryosphere, the researchers had to first frame existing literature on mountain climate change impacts within the concept of L&D.” To do this, they considered peer-reviewed literature published in English between 2013 and 2017 that dealt with issues of glaciers and climate change, and more specifically glacial shrinkage and permafrost degradation. Their search procured 41 papers for the final analysis.
They next considered the geographic distribution of these papers. Surprisingly, the majority of papers focused on the Andes and the Himalayas, while fewer focused on Europe and North America, despite better documentation of climate change effects in those regions. Overall, none of the papers explicitly mentioned L&D while highlighting glacial and climate change processes. Half of the papers focused on slow-onset processes, namely changes in river runoff and water availability, while a smaller subset focused on physical changes to landscapes due to glacial retreat and ecosystem changes.
The second biggest group of papers examined both slow-onset and sudden-onset processes. Finally, the smallest group of papers focused solely on sudden-onset processes, mainly glacial outburst floods (GLOFs), which can also be considered a combination of both slow and sudden-onset processes.
Next, the researchers grouped the socio-economic impacts found in the reviewed papers. These groups included cultural impacts, impacts to livelihoods, loss of productivity and revenue, loss of natural resources, loss of lives, loss of security and social order, and damages to property and assets. The group with the highest number of papers was damage to and loss of natural resources, followed by loss of productivity and revenue.
The timeframes for the impacts were also considered. More than half of the papers examined potential future impacts and often highlighted strategies to address them.
A majority of the papers fell within the researchers’ avoidable L&D category, meaning they could be mitigated with the right actions. A smaller subset were categorized as unavoidable L&D, impacts that could have been prevented if the correct steps were taken, while only two papers were identified as avoided L&D. Some papers suggested that glacial retreat was unavoidable because of the delayed response of glaciers to climate change, meaning they will continue to shrink in the future even if mitigation measures are undertaken. Other papers, however, highlight that when comparing low-emission to high-emission scenarios, there is a discernible difference in glacial retreat; thus, it may be partly avoidable.
From their literature review, the researchers made several observations. First, they note the current disconnect between mountain cryosphere research and L&D, which indicates that the concept of L&D has yet to be analyzed and applied for these environments. Second, their study reveals that L&D in the mountain cryosphere is a worldwide phenomenon occurring in all major mountain ranges with a higher proportion of L&D in developing rather than developed countries. Third, they highlight the seven groups of L&D outlined above as particularly relevant to the mountain cryosphere. Out of these, the non-economic ones, of which five of the seven can be considered, have attracted attention in research and policy due to the loss of values associated with glacial retreat, such as community and self-reliance.
Finally, the researchers propose an analytical and process-based framework to understanding L&D in the mountain cryosphere, considering the driving physical processes, the secondary physical processes (slow-onset and sudden events), and the associated societal impacts. These three elements will help to foster an understanding of how L&D is “connected, driven, and caused by climate and cryosphere change,” in addition to the social, political, and economic factors.
The driving physical processes in the framework are broken down into three elements: glaciers, snow, and permafrost, which are all primarily affected by the warming climate. The secondary primary processes are more numerous and include impacts such as GLOFs, losses of seasonal melt water, and ecosystem changes. Finally, the tertiary societal impacts include loss of lives, loss of natural resources and livelihoods, and loss of income, security, and social order.
This L&D framework highlights the cascading impacts in the mountain cryosphere. One illustration of this is glacial retreat leading to a reduction in water availability, followed by low agricultural yields which lead to a loss of income to farmers.
Overall, this study represents an initial advance of research and policy for L&D in the mountain cryosphere. The concepts and framework outlined in the study may well encourage future research on the subject and ultimately lead to policies to better manage L&D in the mountain cryosphere.
Between 2003 and 2010, the Greenland Ice Sheet and its associated glaciers experienced a mean annual mass loss of 186 Gt, double the rate between 1983 and 2003. Though this mass loss has been linked to global sea-level rise through meltwater discharge, heightened glacial runoff has also been hypothesized to have another important effect: increasing marine primary productivity through nutrient fertilization. This hypothesis was the focus of a recent study published in Nature Communications, which reports that the upwelling of nitrate-rich deep seawater driven by subglacial discharge— not the meltwater itself— is likely the main driver of the increased productivity.
This question about the impact of heightened glacial runoff is important both for academic research on marine ecosystems and for assessing the future of oceans to serve as carbon sinks. The photosynthesis represented by primary productivity is one of the key mechanisms through which carbon dioxide dissolved in seawater can be captured and retained in the oceans.
During the spring, marine primary productivity off the coast of Greenland increases as phytoplankton bloom. Then, in the summer, productivity usually diminishes. Recently, however, there have been summer phytoplankton blooms accounting for up to half of annual primary productivity. The goal of the study was to examine these changes to summer productivity and see how they relate to nutrient availability during the meltwater season.
The researchers first assessed which nutrient deficiency limits summer primary productivity off of Greenland. In most parts of the high-latitude Atlantic, summer primary productivity is limited by iron or nitrate deficiencies. However, in Greenland, few studies had previously examined the nutrient limits to phytoplankton blooms.
The researchers found that iron values were the most positive near the coasts, while offshore values were close to zero. On the other hand, nitrate values were deficient near the coasts and offshore. These results indicate that iron may help trigger the summer blooms while also inhibiting the drawdown of nitrate by plankton, leading the researchers to conclude that the availability of nitrate is likely the constraint on summer primary productivity.
Is heightened glacial runoff supplying more iron and nitrate, contributing to the summer phytoplankton blooms? Iron concentrations from glacial runoff were comparatively low, unlikely to trigger the blooms given the already iron-rich waters, the authors concluded. Furthermore, in Greenland, glacial runoff supplying iron can have a negative impact on primary production. It has this effect by reducing the availability of other nutrients and by creating cloudy sediment plumes from glacial flour composed of fine-grained rock particles created by glaciers grinding over underlying bedrock. These cloudy plumes limit light availability, says lead author Mark Hopwood, who spoke with GlacierHub about the paper. In contrast, he said, nitrate concentrations were found to be even lower than iron ones, only enough to have a very small effect on phytoplankton blooms.
While the meltwater from glacial runoff is unlikely to be the trigger of the summer plankton blooms off Greenland, the researchers determined marine-terminating glaciers to represent another aspect of glacial discharge.
Unlike their land-terminating counterparts, marine-terminating glaciers discharge meltwater through sub-glacial plumes. This discharge, once injected into the water at the glacial grounding line, entraps nutrient-rich deep seawater in a rising plume. This upwelling, if it occurs at the right depth, takes nitrate-rich waters to the photic zone where light is sufficient for photosynthesis, driving the phytoplankton blooms.
The researchers found four scenarios through which plume upwelling affects nutrient delivery near marine-terminating glaciers, with glacial grounding line depth the primary influence on the efficacy of this delivery. Under the first scenario, a nutrient-rich plume is generated by sub-glacial discharge. However, the glacier is too deep, and the plume is unable to reach the photic zone. In the second scenario, the glacier is in the optimum depth zone, and the nutrient-rich deep sea water is upwelled to the photic zone, enhancing the phytoplankton bloom. In the third scenario, the grounding line depth shallows because of glacial retreat. This shallowing limits the amount of seawater entrapped by the sub-glacial discharge. The seawater that is entrapped lacks the nutrients of deeper waters, thereby lessening the positive effects of the upwelling on phytoplankton blooms. In the final scenario, the glacier has retreated inland and no longer ends in the ocean, so no upwelling is generated.
After delineating these four scenarios, the researchers next simulated the plume upwelling effect to find the optimum conditions for peak nitrate flux to be upwelled to the photic zone. According to Hopwood, each fjord-glacier system in Greenland has unique physical characteristics, such as fjord depth and annual discharge volume.
This means that the optimum conditions for each system varies regionally. As a general rule of thumb, shallow glacier grounding line depths below 100 m will likely lead to low productivity, while grounding line depths between 400 and 600 m will likely be linked with high productivity, according to Hopwood. Other factors also affect summer marine productivity including turbidity and the depth of the photic zone. However, the plume upwelling of nutrients appears to be the dominant factor.
The future of marine productivity off Greenland under climate change will be determined by glacier grounding line depths, which may remain as they currently are or migrate into the optimum zone for subglacial discharge, triggering the upwelling of nitrate nutrients. Shallow glacier grounding line systems are likely to have already experienced peak nitrate supplies, while the peak for deeper systems will likely occur in the future if current retreats continue. For the 243 Greenland glaciers that have been mapped for bed topography, 55 percent will retreat onto land in the future, reducing the ice sheet-to-ocean nutrient fluxes driving summertime phytoplankton blooms.
What happens to the plume upwelling of nutrients in Greenland ultimately depends on climate change and subsequent glacier retreats. One subject for future study that could help improve understanding of marine productivity is the influence of icebergs, says Hopwood. The largest icebergs usually extend far below the ocean surface, hypothetically allowing them to “act as miniature nutrient ‘pumps’ as they melt,” Hopwood told GlacierHub. This is similar to what occurs with glaciers on a larger scale. Yet icebergs are more difficult to study and will require interdisciplinary work between both physicists and chemists to examine how icebergs affect the water column and phytoplankton.
Taken together, this research on the effects of different kinds of glaciers on phytoplankton blooms is key to a better understanding of marine ecosystems, helping scientists to assess the ability of the oceans to serve as sinks for the carbon dioxide that we humans continue to release.
Dissertation Examines Climate Change on a South Asian River
From the Dissertation: “What is worrying is that despite a mammoth amount of research and clear evidence, climate change and its effects find no place in the bilateral negotiations and the existing draft of the Teesta agreement. It is a clearly visible ticking time bomb and yet, large dams continue to be built and the signs continue to be neglected or at best, be ‘fixed’ by temporary measures. Governments at state and central level might have different agendas, but they are unanimous in their dismissive attitude towards the profound effects of climate change sweeping across the basin.”
From World Water Week: “World Water Week is the annual focal point for the globe’s water issues. It is organized by SIWI. In 2018, World Water Week will address the theme ‘Water, ecosystems and human development.’ In 2017, over 3,300 individuals and around 380 convening organizations from 135 countries participated in the week. Experts, practitioners, decision-makers, business innovators and young professionals from a range of sectors and countries come to Stockholm to network, exchange ideas, foster new thinking and develop solutions to the most pressing water-related challenges of today.”
From Regional Environmental Change: “The mountain cryosphere, which includes glaciers, permafrost, and snow, is one of the Earth’s systems most strongly affected by climate change… In international climate policy, there has been growing momentum to address the negative impacts of climate change, or ‘Loss and Damage’ (L&D) from climate change. It is not clear exactly what can and should be done to tackle L&D, but researchers and practitioners are beginning to engage with policy discussions and develop potential frameworks and supporting information. Despite the strong impact of climate change on the mountain cryosphere, there has been limited interaction between cryosphere researchers and L&D. Therefore, little work has been done to consider how L&D in the mountain cryosphere might be conceptualized, categorized, and assessed.”
Of the many impacts caused by climate change, sea-level rise threatens to be one of the most devastating due to the thermal expansion of the oceans and the melting of ice and glaciers on land. These impacts, along with numerous others related to rising global temperatures, may in the future motivate a country, a group of countries, or even a very rich individual to pursue solar geoengineering, a controversial proposal for limiting the amount of solar radiation that reaches the Earth’s surface. A recent study in The Cryosphere assessed the efficacy of such a solar geoengineering attempt at limiting global sea-level rise.
Geoengineering, as it relates to climate change, falls into two categories. The first, atmospheric carbon removal, entails physically removing carbon dioxide from the air to reduce greenhouse gas concentrations and limit temperature rise. The second, solar geoengineering, involves injecting sulfur dioxide or another aerosol into the stratosphere to reflect a portion of incoming solar radiation, again limiting temperature rise.
Because of the temperature-reducing effect of solar geoengineering, research suggests that such a proposal would also reduce sea-level rise. However, just how effective solar geoengineering could be in limiting sea-level rise had not yet received sufficient research, according to Peter Irvine, the lead author of the study, who spoke with GlacierHub. Irvine and his team of scientists hoped to “shed some light on the complexities of the sea-level rise response to solar geoengineering, make an initial evaluation of its efficacy, and to bring this issue to the attention of the cryosphere research community,” Irvine told GlacierHub.
Initially, the researchers conducted a literature review on the small number of studies that explored the cryosphere’s potential response to solar geoengineering. A 2009 study that examined the Greenland Ice Sheet found that under a scenario where atmospheric concentrations were quadrupled, solar geoengineering could slow or even prevent the collapse of ice sheets. Conversely, a 2015 study determined that while solar geoengineering could slow melting, glaciers and ice sheets would not recover to past states. Lastly, a 2017 study focusing on high-mountain Asia, found that solar geoengineering would stop temperature increases; however, 30 percent of glaciated area would still be lost.
Following the literature review, the researchers evaluated the potential effect of solar geoengineering on three aspects of sea-level rise. The first aspect was thermosteric sea-level rise, or more simply, the thermal expansion of ocean waters. Because temperature is the dominant influence on thermosteric sea-level rise (warmer water is less dense than cooler water), the decrease in solar radiation reaching the Earth’s surface due to solar geoengineering would limit sea-level rise.
Secondly, the researchers examined solar geoengineering’s effect on the surface mass balances of glaciers and ice sheets. Surface mass balance is primarily affected by the surface melt rate, which is the result of the availability of energy at the surface of the ice. Thus, a change in solar radiation reaching the Earth’s surface would likely reduce surface melt. The analysis of large volcanic eruptions offers an analogous example to what might happen to surface melt if solar geoengineering were pursued because the dust and ash released during an eruption blocks some incoming solar radiation.
One study examined by the researchers showed that surface mass balances in Greenland were at their maxima in the year after the El Chicón and Pinatubo eruptions in 1982 and 1991, respectively. Similarly, another study in Greenland found that in the years following the El Chicón and Pinatubo eruptions, surface runoff was the third lowest and lowest, respectively, between the years 1958 and 2006, further reinforcing the expectation that solar geoengineering would limit surface mass balance reductions.
In addition to its effect on temperature, solar geoengineering would also affect the global hydrologic cycle and subsequently sea-level rise. Warming temperatures due to climate change will likely lead to more precipitation worldwide; however, if solar geoengineering is pursued, this increase could be offset. This precipitation change would affect both Greenland and Antarctica, according to Irvine.
In Greenland, surface melt changes, not precipitation accumulation, are the primary influence on surface mass balances; therefore, solar geoengineering would likely have a positive effect by reducing temperatures, with the decrease in precipitation unlikely to lead to mass balance decline. In Antarctica, on the other hand, increased precipitation due to climate change has had a positive effect on surface mass balance, thus a decrease in precipitation due to solar geoengineering would negatively impact mass balances.
The third and final sea-level rise aspect examined by the researchers to evaluate the efficacy of solar geoengineering was ice lost through calving and eventual ice-sheet collapse. Calving, the scientific name for icebergs breaking off a glacier at its terminus, depends on the speed at which ice flows, which itself is driven by climatic changes.
In Antarctica, warming water known as circumpolar deep water (CDW) is the primary driver of calving. CDW is pushed below and then up into glacial cavities by surface winds, where the warm water melts the ice. This melting drives calving and leads to the thinning of glaciers.
While solar geoengineering would likely lower air temperatures, it is unlikely to reduce the temperature of CDW and limit melting and subsequent calving from below. In addition, a 2015 study found that solar geoengineering is unlikely to limit the upwelling of CDW and could even increase upwelling. However, this finding has yet to be replicated, according to Irvine, and it is not clear whether the results are exclusive to the model used.
There is also no guarantee that solar geoengineering would be able to prevent glacial collapse due to marine ice sheet instability. This collapse occurs when a glacier retreats past its grounding line (where ice meets underlying bedrock) and continues to retreat inland until it reaches another stabilizing ridge. The process might already be occurring at West Antarctica’s Thwaites and Pine Island glaciers, which are extremely vulnerable due to the sloping topography upon which they rest.
Nevertheless, retreat and possible collapse might be preventable, says a 2016 study. It showed that returning water to cooler conditions reversed glacial retreat. This finding indicates solar geoengineering may be useful to prevent marine glaciers from destabilizing. While encouraging, it remains likely that certain glaciers, especially those in West Antarctica, will continue to experience significant ice loss regardless of whether solar geoengineering is pursued or greenhouse gas emissions are dramatically reduced.
Based on their study, the researchers lay out four areas in need of future research. First is the need to evaluate the sea-level rise response to solar geoengineering scenarios in conjunction with climate change scenarios so that the efficacy of solar geoengineering and greenhouse gas emissions reductions can be compared. Second is the need to employ regional models of surface mass balance in order to assess the effectiveness of solar geoengineering to limit mass balance losses. Third, the researchers recommend additional evaluation of the effect of solar geoengineering on the CDW upwelling and stability of glaciers and ice-shelves. Finally, the researchers recommend the evaluation of sea-level rise risk, alongside the numerous other risks and challenges associated with solar geoengineering.
The potential for solar geoengineering to limit sea-level rise from the cryosphere is still up for debate, but as this study shows, it may have the potential to reduce temperature and curb some aspects of sea-level rise, including surface mass balance losses and ocean thermal expansion. However, for other aspects, mainly the melting of glaciers from below by warm waters, it may be unlikely that solar geoengineering can limit sea-level rise contributions. Nonetheless, when it comes to the society-altering impact of sea-level rise, solar geoengineering could be a part of humanity’s response.
This week check, out this video from Ice Alive which shows unique cloud patterns over a glacier in Greenland. The cloud patterns are likely influenced by glacial ice, which cools the air above the surface of the glacier. A prime example of this is what is known as katabatic winds, which occur when cooling produces a cold, dense air mass above a glacier that then flows downhill.
The remote and mountainous Kamchatka Peninsula in eastern Russia is home to over 600 glaciers and 30 active volcanos. Like most glaciers around the world, the glaciers of Kamchatka have been in retreat due to climate change. However, not all of the glaciers in Kamchatka are retreating; some have remained stable, while others have even advanced. One region, the northern Kluchevskoy Volcanic Group (NKVG) in central Kamchatka, where glaciers have advanced, was the focus of a recent study in Geosciences, which examined this anomaly and the overall behavior of the area’s glaciers.
The NKVG, is home to multiple active volcanos. Two, the Klyuchevskoy and the Bezymianny, have erupted over 90 and 20 times, respectively, since 1800. The NKVG is also home to 15 named glaciers. On the whole, the total glacial area across the peninsula shrank by 11 percent from the 1950s to 2000. This shrinking trend was even more pronounced recently with total glacier area decreasing 24 percent from 2000 to 2014. Nonetheless, several of the glaciers in the NKVG were found to have advanced despite rising temperatures.
This finding served as the motivation for the study, which aimed to examine these advancing glaciers in greater detail, according to lead author Iestyn Barr, who spoke to GlacierHub about the research. In the past, monitoring of the glaciers in the NKVG had been hindered by extensive glacial debris cover, the logistical challenges of conducting fieldwork in remote Kamchatka, and the lack of cloud-free satellite images due to the peninsula’s climate.
To surmount these challenges, the researchers utilized ArticDEM, a free, high-resolution elevation satellite dataset for the Arctic developed through an initiative by the National Geospatial Intelligence Agency and National Science Foundation. The dataset recently became available for Kamchatka.
The ArticDEM data allowed the researchers to map and monitor glacial variations in a way that had not been possible before. For example, debris cover previously made it difficult to distinguish the margins of a glacier, but with ArticDEM the researchers were able to delineate glacial margins by identifying breaks in the glaciers’ slope. In addition, the data covered multiple years, allowing the researchers to monitor changes over time. The primary drawback of the data, according to Barr, is that there are gaps: not all glaciers are covered entirely for multiple time-periods, and the time-periods are not always the same for each glacier.
Overall, the study’s analysis between 2012 to 2016 revealed that glaciers in the NKVG cover an area of over 182 km2, with most glaciers originating from a central icefield near two of the area’s volcanos and extending up to 20 km in length. Debris-covered glaciers make up 65 percent of all glacial area.
Of these glaciers, three glaciers in the NKVG were found to have advanced over the observed time period with the Shmidta glacier experiencing the biggest advance of 120 m between July 2012 to April 2014 and a further 60 m advance by October 2015. The other two glaciers, the Bogdaovich and Erman, advanced too, with the Bogdaovich advancing 40 m between April 2013 and October 2015 and Erman advancing 30 m between September 2013 and February 2016.
The researchers also examined changes to the surface elevations of glaciers in the NKVG, finding that most changes were the result of the deposition of volcanic material. A 2013 eruption of the Klyuchevskoy volcano deposited debris on parts of the Bogdanovich Glacier, causing a 13 m increase in surface elevation. On the other hand, other areas of the Bogdanovich, as well as other glaciers in the NKVG, experienced decreases in surface elevation likely as a result of increased ice melt caused by hot volcanic debris.
In the end, the researchers determined a connection between the anomalous advancing glaciers and the increased glacier surface elevations. Volcanic debris, which are deposited on glaciers in the aftermath of an eruption, increase elevation and insulate the glacier by absorbing solar radiation. This allows the glacier to remain stable or advance.
All three of the glaciers in the NKVG that advanced also had debris cover, the authors note. The Shmidta Glacier was covered during an eruptive period for the Klyuchevskoy volcano from 2005 to 2010, while the Bogdanovich and Eram glaciers were covered in the 1940s and 1950s, respectively.
Finally, the researchers assessed the velocity of the glaciers in the NKVG, finding that they ranged from 5 to 140 m a year. The highest velocities were found near the central sections of the largest glaciers close to the top of the Ushovky caldera (a large volcanic crater), with velocity decreasing further down the glaciers. On the whole, 21 percent of the glacial area in the NKVG was classified as low-activity or simply showing no evidence of flow, with the remaining area classified as active. These sections of the glaciers were, for the most part, in the ablation (melting) zone at the lower end of the glacier.
Analyzing the state of glaciers in the isolated Kamchatka Peninsula has long been a challenge. Fortunately, the recent availability of ArticDEM data aided the researchers in examining the changing glaciers of the NKVG in a novel way. In the future, the researchers hope to further employ ArticDEM data to analyze more of the Kamchatka glaciers and to map the glacial geomorphology of the greater region, including Eastern Siberia, to determine the extent of glaciers in the past, according to Barr.
This Photo Friday, explore the massive South Patagonian Icefield. Along with its northern counterpart, this icefield makes up the largest expanse of ice in the Southern Hemisphere outside of Antartica, thanks to the regions favorable climate. When westerly winds traveling across the Pacific reach Patagonia they are lifted upwards by the Andes Mountains which cools and condenses the air, forming clouds and heavy precipitation.
Just how heavy? The western side of the Patagonia Icefields receive an astonishing 160 inches of rain and snow a year. While the eastern side receives less, as the moisture content of the air masses that rose on the western side is depleted, the area still receives a substantial 40 inches. When this precipitation falls as snow and freezes on the glaciers, it adds mass; however, in recent times, the glaciers in South Patagonia have retreated due to climate change. The Jorge Montt, for example, has retreated 13 kilometers between 1984 and 2014 and at the peak of its melting was thinning by 100 feet a year. Check out the images below of four expansive glaciers in Southern Patagonia from NASA’s Earth Observatory.
West Antarctica’s Pine Island Glacier (PIG) is the fastest melting glacier in Antarctica, making it the single biggest contributor to global sea-level rise. The main driver of this rapid loss of ice is the thinning of the PIG from below by warming ocean waters due to climate change. However, a recently published study in Nature Communications discovered a volcanic heat source beneath the PIG that is another possible driver of the PIG’s melting.
The study was a result of a larger project funded by the National Science Foundation and the U.K. National Environmental Research Council to “examine the stability of the Pine Island Glacier from the terrestrial and the ocean side,” according to the lead author Brice Loose, who spoke with GlacierHub about the research.
The West Antarctic Ice Sheet (WAIS), which includes the PIG, sits on top of the West Antarctic Rift System that includes 138 known volcanoes. It is difficult, however, for scientists to pinpoint the exact location of these volcanoes or the extent of the rift system, because most of the volcanic activity occurs below kilometers of ice.
Warming ocean temperatures due to climate change have long been identified as the primary contributor to the extensive melting of the PIG and other glaciers that transport ice from the WAIS. This melting is largely driven by Circumpolar Deep Water (CDW), which melts the PIG from below and leads to the retreat of its grounding line, the place where the ice meets the bedrock.
To trace CDW around coastal Antarctica, the scientists used helium isotopes, specifically He-3, because CDW is widely recognized as the principal source of He-3 in the waters near the continent. For this study, the scientists used historical data of helium measurements from the Weddell, Ross, and Amundsen seas around Antarctica. They looked at the 3 seas, all of which have CDW, and examined differences in He-3, which could have come from volcanic activity.
By tracing the glacial meltwater produced by the CDW, the researchers discovered a volcanic signal that stood out in their data. The helium measurements utilized were expressed by the percent deviation of the observed data from the atmospheric ratio. For the observed CDW in the Weddell Sea, this deviation was 10.2 percent. In the Ross and Amundsen Seas, it was 10.9 percent. However, HE-3 values gathered by the team during expeditions to the Pine Island Bay in 2007 and 2014 differed from the historical data.
For this data, the percent deviation was considerably higher at 12.3 percent, with the highest values being near the strongest meltwater outflow from the PIG’s front. Additionally, these high helium values coincided with raised neon concentrations, which are usually an indication of melted glacial ice. The helium was also not uniformly distributed. This suggests it originated from a distinct meltwater source and not from across the PIG’s entire front.
With this knowledge in hand, the team of scientists endeavored to identify the source of the HE-3 production. The Earth’s mantle is the largest source of HE-3, although it is also produced in the atmosphere and during past atmospheric tests of nuclear weapons through tritium decay. These two sources, however, could only account for 0.2 percent of the 2014 data.
Another potential source was a fissure in the earth’s crust directly below the PIG, where He-3 could rise from the mantle. However, this source was ruled out as it would have a strong thermal signature, something that was not discovered by mapping expeditions.
The researchers then considered another source: a volcano beneath the PIG itself, where He-3 escapes from the mantle in a process known as magma degassing. The He-3 could be transported by glacial meltwater to the PIG’s grounding line, where the ice meets the underlying bedrock. At this line, the ice shifts due to the ocean tides, allowing the meltwater and the He-3 to be discharged into the ocean. After identifying a subglacial volcano as the most likely source of the elevated He-3 levels near the PIG’s front, the scientists next calculated the heat released by the volcano in joules per kilogram of sea water at the front of the glacier. It turned out that the heat given off by the volcano constitutes a very small fraction of the overall mass loss of the PIG compared to the CDW, according to Loose. In total, the volcanic heat was 32 ± 12 joules kg-1, while the heat content of the CDW was much larger at 12 kilojoules kg-1. Nevertheless, if the volcanic heat is intermittent and/or concentrated over a small surface area, it could still have an impact on the overall stability of the PIG by changing its subsurface conditions, said Loose. There is also the possibility that the continued melting of the PIG could lessen the pressure and weight on the volcano, spurring more volcanism and subsequent melting.
The presence of an active volcanic heat source beneath the world’s fastest-melting glacier is a disturbing discovery that threatens to accelerate the PIG’s contribution to future sea-level rise. To develop a better understanding of how the volcano might impact the PIG, Loose stated that future studies should examine how the volcanic signal varies from year to year and attempt to pinpoint the likely location of the volcano itself beneath the ice.
Mercury Deposited as Snowfall Incorporated into Meltwater
From the Journal of Environmental Sciences: “The Tibetan Plateau (TP) is recognized as the ‘Water Tower of Asia.’ Yet our understanding of mechanisms influencing incorporation of mercury (Hg) into freshwater in mountain glaciers on the TP remains quite limited. Extensive sampling of environmental matrices (e.g., snow/ice) were conducted on the East Rongbuk glacier on Mt. Everest and Zhadang glacier on Mt. Nyainqentanglha for Hg speciation analysis. Speciated Hg behaved quite different during snowmelt: a preferential early release of DHg (dissolved Hg) was observed at the onset of snowmelt, whereas PHg (particulate-bound Hg) and THg (total Hg) become relatively enriched in snow and released later.”
Fish Diversity in Himalayan Streams Varies in Glacial and Rain-fed Streams
From Environmental Biology of Fishes: “Assessment of headwater biodiversity is essential for maintaining upstream downstream ecosystem services of rivers. Fish biodiversity assessment was conducted in the headwater tributaries of the glacial-fed Tamor River and rain-fed Kamala River in eastern Nepal. A total of eight sites were sampled… A total of 8940 fishes belonging to four orders, 10 families, 26 genera and 34 species were enumerated. Significant variation in Shannon-Weiner Diversity Index (p = 0.015) and Species Richness (p = 0.005) between the glacial fed and rain fed streams with higher values of these indices in the rain fed tributaries… These findings indicate that fish assemblages reflect the different ecological regimes of the glacial-fed and rain-fed headwaters.”
Glacial Areas in Colombia Have Fewer Black Flies
From Acta Tropica: “Vector ecology is a key factor in understanding the transmission of disease agents, with each species having an optimal range of environmental requirements. Scarce data, however, are available for how interactions of local and broad-scale climate phenomena, such as seasonality and the El Niño Southern Oscillation (ENSO), affect simuliids. We, therefore, conducted an exploratory study to examine distribution patterns of species of Simuliidae along an elevational gradient of the Otún River in the Colombian Andes, encompassing four ecoregions… Species richness and occurrence in each ecoregion were influenced by elevation, seasonality, and primarily the warm El Niño and cool La Niña phases of the ENSO.”
The Pine Island Glacier (PIG) is losing ice rapidly. During the past 25 years, the ice of the PIG and its neighboring glaciers in west Antarctica’s Pine Island Bay thinned between 3.9 and 5.3 meters a year, accounting for about 5 to 10 percent of observed global mean sea-level rise. Before 2015, however, the front of the PIG had been at a relative standstill since the 1940s, not retreating as one might expect of a melting glacier. Why? To account for this unique situation, a recently published study in The Cryosphere points to ridges below the ice that likely held the PIG’s ice front in place despite its rapid melting.
In August 2015, the long steady front of the PIG changed significantly when large sections of ice broke off during a calving event when the glacier retreated upstream and its orientation shifted. This change presented an exciting opportunity in 2017 for researchers from the Alfred Wagner Institute for Polar and Marine Research to map the seafloor formerly covered by the PIG.
To complete this mapping project, the researchers employed an echo sounder mounted to the hull of the research vessel RV Polarstern, in addition to complementing remote sensing data acquired by satellite. The information acquired by the expedition through echo sounding showed the seafloor features that were present below the PIG. With this data in hand, the researchers had the idea to correlate this information with satellite data from the past to the present to better understand the role of these features for the calving behavior of PIG, according to lead author Jan Erik Arndt, who spoke with GlacierHub about the study.
These survey methods revealed a complex, underwater landscape once covered by the PIG. The discoveries included a 10-kilometer long ridge and two other high points. At its deepest point, Pine Island Bay reaches down over 1,000 meters, while the submarine ridge peaked at 375 meters below the ocean’s surface and the two downstream high points peaked at 350 and 250 meters below the surface
How did these sub-surface features impact the PIG? Satellite data from January 1973 until March 2005 showed a rumple in the PIG’s ice above the location of shallowest section of the underlying ridge. A glacial rumple is similar to a bump on a beach towel that suggests there is a beach toy or pile of sand below it. In the case of the PIG, the ridge below the ice acts as an obstacle in the the way of the ice, leading to a raised section of the glacier directly above the point of contact between it and the ridge. This rumple is not observed after March 2005 in the satellite data, indicating that the ice after this date had thinned to such a degree that it either was no longer in contact with the ridge or was too light to produce a signature on the surface.
The loss of contact with the ridge was consequential. In the time before this separation when the PIG was in contact with the underwater ridge, the ridge acted as a “pinning point,” holding it in place. However, after the ice had thinned considerably, the ridge no longer acted as a restraint on the PIG. As a result, in the time since there was evident contact between the two, four major calving events occurred.
The first of these events took place in 2007 when the PIG advanced and made contact with one of the subsurface downstream high points (A in figure 3). This impact placed what is known as “back stress” on the glacier upstream from the point of contact, causing rifts to form in the ice and ultimately leading to the calving event.
The process leading to the 2011 calving event was similar, the researchers state. In this instance, the second subsurface high point (B in figure 3) trapped a dense cluster of icebergs between it and the PIG ice shelf, placing back stress on the upstream ice leading to the calving event.
The 2015 event was different: The ice-flow velocity of the northern edge of the PIG’s ice shelf was nearly at a stand still, whereas the velocity of the ice shelf’s central and southern edges increased. Further, the direction of the northern edge’s ice flow shifted around 3 degrees clockwise, while the direction of the central and southern edges did not change (C in Figure 3). The reason? The northern edge of the ice-shelf was likely making slight contact with the submarine ridge, according to the authors.
As a result, the calving line that had not changed orientation in decades finally did change due to the loss of contact between the ice and its previous pinning points as well as from melting from below driven by warm ocean waters. The most recent calving event which occured in 2017 happened along the same orientation, which aligns with a new pinning point to the north near Evans Knoll, a small snow-covered hill that rises above sea level. The point near the knoll is likely one of the last anchors acting on the PIG, according to Arndt.
This new calving line and loss of contact with past pinning points could have grave implications for PIG. A 2017 study on the PIG and a number of other glaciers in the area found that changes to a glacier’s ice shelf propagate upstream within just a few years. For the PIG, this likely means the glacier’s flow will speed up and thinning will increase, leading to further melting.
It is unlikely the PIG’s calving line will retreat much further over the next few years thanks to the new pinning point stabilizing the glacier near Evans Knoll. However, the authors note that there is continued thinning due to melting. This thinning has the potential to destabilize the glacier and unfortunately may have already started, according to Arndt. The large icebergs produced by the recent calving events have broken up into smaller icebergs much more quickly due to the thinner ice than events in the past, when they remained stable for longer. This ongoing breakup and subsequent melting of calved icebergs will contribute to already rising global sea-levels, threatening the millions of people who live along the coast. And unlike the ridges that held the front of the PIG for decades, many coastal communities will not have anything to hold back the sea.