From Cryosphere Journal: “Iceberg discharge from the Greenland Ice Sheet accounts for up to half of the freshwater flux to surrounding fjords and ocean basins, yet the spatial distribution of iceberg meltwater fluxes is poorly understood. One of the primary limitations for mapping iceberg meltwater fluxes, and changes over time, is the dearth of iceberg submarine melt rate estimates. Using a remote sensing approach to estimate submarine melt rates during 2011–2016, we find that spatial variations in iceberg melt rates decrease with latitude and increase with iceberg draft. Overall, the results suggest that remotely sensed iceberg melt rates can be used to characterize spatial and temporal variations in oceanic forcing near often inaccessible marine-terminating glaciers.”
Discover more about the use of remote sensing for studying glacier melt rates here.
The History of Civilizations in the Arctic
From “Arctic Modernities: The Environmental, the Exotic and the Everyday“: “Less tangible than melting polar glaciers or the changing social conditions in northern societies, the modern Arctic represented in writings, visual images and films has to a large extent been neglected in scholarship and policy-making. However, the modern Arctic is a not only a natural environment dramatically impacted by human activities. It is also an incongruous amalgamation of exoticized indigenous tradition and a mundane every day. The chapters in this volume examine the modern Arctic from all these perspectives. They demonstrate to what extent the processes of modernization have changed the discursive signification of the Arctic. They also investigate the extent to which the traditions of heroic Arctic images – whether these traditions are affirmed, contested or repudiated – have continued to shape, influence and inform modern discourses.”
From Volcano Café: “What makes a volcano dangerous? Clearly, the severity of any eruption plays a role. So does the presence of people nearby. But it is not always the best-known volcanoes that are the most dangerous. Tseax is hardly world-renowned, but it caused a major volcanic disaster in Canada. And sometimes a volcano can be dangerous without actually erupting. Lake Nyos in Cameroon is a well-known -and feared- example. What happened in the eruption of Mount Kazbek that made it such a catastrophe?”
Explore the famous volcanic disaster that resulted from a glacier-melting event in 2002 here.
Though I lived in China’s Xinjiang Uyghur Autonomous Region for almost two years, it was only when I was in the heart of the Tian Shan mountains, my motorcycle meandering its way around fallen rock, sheep herds and horses, that I felt truly at home. Just a few hours outside of the city of Shihezi, inspiring peaks soared over 4000 meters. Though I had no scientific data to support my feeling that these stunning vistas were impermanent, over the course of my stay there were fewer and fewer clear days to see the cresting glacier-capped peaks from my apartment window. The haze even began to influence my weekend trips deep into the mountains, sometimes choking off the views far outside of the city. There is too much pollution in these mountains, not like when I was a child— a common refrain that echoed among many Kazakh and Mongol herders who made their home there.
In a recent article in the journal of Arctic, Antarctic, and Alpine Research, Baojuan Huai and a team of Chinese researchers use remote sensing to put scientific data in the place of the herders’ and my own perceptions. The glaciers of the Tian Shan— the impressive mountain range that historically has divided the region’s agrarian oasis-states to the south and nomadic communities to the north— are in danger of disappearing. The authors demonstrate that in the Chinese Tian Shan, the total area of the glaciers studied has decreased by 22 percent over a fifty year period. The data also shows that glacier retreat is a variable within different regions of the Tian Shan— the result of a convergence of factors both human-caused and natural.
China is home to a baffling 46,377 glaciers. The Xinjiang Uyghur Autonomous Region contains 18,311 of them. The Tian Shan, which cuts across Xinjiang into Kazakhstan and Kyrgyzstan, boasts the largest number of glaciers in northwest China. These glaciers provide invaluable solid reservoirs to agriculture, animal husbandry, and industry in the region. When considering the Tian Shan range alone, the glacial loss will continue to have a severe impact on the livelihoods and ecology of Xinjiang, according to Weijun Sun, one of the paper’s authors. “Warming temperatures are causing a real reduction to glaciers across China, and ablation is occurring constantly, negatively impacting regional ecology,” he said in an interview with GlacierHub.
To acquire data for so many glaciers, the team utilized remote sensing technology, which relies on satellites to monitor different sites, using automated glacier mapping technology to distinguish glaciers from other features. Remote sensing alleviates many of the difficulties typically faced in conducting research on glaciers, which are often remote and difficult to access, according to Sun. “Remote sensing is a fantastic tool, expanding the scope of what we are capable of measuring. With this technology we can now measure things like the amount of reflectance coming from under the surface, or the temperature at the base,” he stated.
For the study, the team selected glaciers that covered a range of variables: glaciers large and small, debris-covered and debris-free, and at high and low elevations were all represented. The research shows that over the period studied, 182 Tian Shan glaciers disappeared, and several large glaciers divided into multiple small glaciers. The percentage of area reduction tended to be higher in small glaciers than in large glaciers, with small glaciers more likely to shrink significantly or disappear entirely.
Glaciers across the Tian Shan experienced a real loss over the period studied, but the rate of change between regions within the mountain range showed significant variability. While glacier loss in one region was as low as 12 percent, total glacier area loss reached 42 percent in another. This variability is caused by a constellation of factors, according to Sun. “Regional variation is primarily caused by differing historical climatic factors, such as temperature, precipitation, and radiation,” he said.
Over the period under consideration, the annual temperature increase in Xinjiang was 0.29 degree Celsius per decade, almost double the global average. Additionally, annual precipitation increased at a rate of 10.6mm per decade, which increased the sensitivity of glaciers at lower elevations to rising temperatures. However, the extent of these increases were not constant throughout the region.
When considering the causes of intensified areal loss in certain parts of the Tian Shan, looking at the specific topography of individual glaciers is critical, according to Tobias Bolch, a glaciologist at the University of Zurich. “The glaciers in Central Tian Shan receive more accumulation during the summer while glaciers in the outer rages receive more accumulation during winter. These summer-accumulation type glaciers are more sensitive to climate change. In addition, the Central Tian Shan is higher than the outer ranges; hence, the glaciers in the Central Tian Shan can have larger accumulation areas,” he stated in an interview with GlacierHub.
In the decades considered in the study, the mean equilibrium line altitude (ELA)— the point on the glacier at which annual ablation and accumulation are equal— increased in altitude. The increases ranged from only 5 meters for one glacier, to as many as 151 meters in another. The increases in mean glacier elevation indicate that glaciers are unable to survive at the lower elevations they once thrived in. Glaciers have been retreating before the eyes of pastoralists for decades; that Chinese researchers have put data in the place of their inaudible perceptions is cause for celebration, if not another motorcycle trip.
The International Centre for Integrated Mountain Development (ICIMOD), through its Cryosphere Initiative, recently organized a five-day training on using remote sensing (RS) and geographic information system (GIS) to map and monitor glaciers in the Hindu Kush Himalaya (HKH).
Nineteen participants consisting of students and professionals from ICIMOD’s partners in Bhutan, Nepal and Pakistan attended the training organized at the ICIMOD headquarters in Kathmandu, Nepal, in March 2017.
The training aims to build the capacities of national partners on the use of RS and GIS for glacier mapping and monitoring, and it was the 11th of its kind. In addition to Nepal, ICIMOD has organized this training in Pakistan, Myanmar, Bhutan and Afghanistan.
Such trainings help build and enhance the capacities of professionals working in water resources research and management in relation to using RS and GIS for mapping and monitoring glaciers and glacial lakes. Events such as these also open up avenues for research collaborations with and between relevant implementing partners in the region.
As a follow-up to the training programme, six professionals from Tribhuvan University in Nepal will be getting on-the-job training at ICIMOD for the duration of two months. The professional mentoring they will receive while at ICIMOD will help them further develop their RS and GIS skills, and contribute to glacier data generation in the HKH.
By the end of the two months, the six professionals will be able to conduct mapping exercises, which provide information on the status of glaciers and decadal changes. Continual mapping and monitoring of glaciers will provide answers to how climate change is affecting the glaciers of the HKH and also enable experts to identify potential glacial lake outburst flood (GLOF) risks. Further, such mapping and monitoring will also provide evidence for policy makers in the region to understand their fresh water reserves and to enhance their water-related hazard and risk reduction planning.
Through its various capacity building activities, the goal of the Cryosphere Initiative is that the HKH will, in the long run, have an increased number of experts who can independently carry out long-term glacier monitoring.
ICIMOD works in the HKH with eight regional member countries- Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal, and Pakistan. The Cryosphere initiative of ICIMOD is supported by the Government of Norway.
The HKH has the largest glacier area besides the two polar regions and are the source of ten large Asian river systems, providing water to 1.3 billion people, about a fifth of World’s population.
From Science of The Total Environment: “Quantifying fluxes [the action of flowing] of water, sediment and dissolved compounds through Arctic rivers is important for linking the glacial, terrestrial and marine ecosystems and to quantify the impact of a warming climate… This study uses a 8-years data set (2005–2012) of daily measurements from the high-Artic Zackenberg River in Northeast Greenland to estimate annual suspended sediment fluxes based on four commonly used methods: M1) is the discharge weighted mean and uses direct measurements, while M2-M4) are one uncorrected and two bias-corrected rating curves extrapolating a continuous concentration trace from measured values.”
From Applied Geography: “Receding mountain glaciers affect the hydrology of downslope ecosystems with consequences for drinking water, agriculture, and hydropower production. Here we combined land cover derived from satellite imagery and other environmental data from the northern Peruvian Andes into a first differencing regression model to assess wetland hydrologic connectivity… The results indicate that there were two primary spatial driving forces of wetland change in Peru’s Cordillera Blanca from 1987 to 1995: 1) loss in glacier area was associated with increased wetland area, controlling for other factors; while 2) an increase in mean annual stream discharge in the previous 12 months increased wetland area.”
Observation-Based Estimates of Glacier Mass Change
From Surveys in Geophysics: “Glaciers have strongly contributed to sea-level rise during the past century and will continue to be an important part of the sea-level budget during the twenty-first century. Here, we review the progress in estimating global glacier mass change from in situ measurements of mass and length changes, remote sensing methods, and mass balance modeling driven by climate observations. For the period before the onset of satellite observations, different strategies to overcome the uncertainty associated with monitoring only a small sample of the world’s glaciers have been developed. These methods now yield estimates generally reconcilable with each other within their respective uncertainty margins. Whereas this is also the case for the recent decades, the greatly increased number of estimates obtained from remote sensing reveals that gravimetry-based methods typically arrive at lower mass loss estimates than the other methods. We suggest that strategies for better interconnecting the different methods are needed to ensure progress and to increase the temporal and spatial detail of reliable glacier mass change estimates.”
Roundup: Glacier Surface Motion, Black Carbon & Skiing
Remote Sensing Measures Glacier Surface Motion
From ISPRS Journal of Photogrammetry and Remote Sensing: “For monitoring of glacier surface motion in pole and alpine areas, radar remote sensing is becoming a popular technology accounting for its specific advantages of being independent of weather conditions and sunlight… Synthetic aperture radar (SAR) imaging is a complementary information source which has the advantage of providing images all year long, with no limitations in terms of weather condition and imaging time. It can reliably collect data with a pre-defined temporal interval over long periods of time with a ground resolution meeting the demands of glacier monitoring. Additionally, active SAR sensors observe both the amplitude and phase information of the backscattered signal from the ground target.”
Read more about remote sensing in alpine areas here.
Effects of Black Carbon on the Tibetan Plateau
From Advancements in Climate Change Research: “The Tibetan Plateau (TP), which has an abundance of snow and ice cover, is referred to as the water tower of Asia. Melting snow/ice makes a large contribution to regional hydrological resources and has direct impacts on local society and economic development. Recent studies have found that light-absorbing impurities, which may accelerate snow/ice melting, are considered as a key factor in cryospheric changes. However, there have been few assessments of the radiative effects of light-absorbing impurities on snow/ice cover over the Tibetan Plateau. Flanner et al. (2007) coupled a snow radiative model with a global climate model (GCM) and estimated the anthropogenic radiative forcing by the deposition of black carbon in snow averaged 1.5 W m−2 over the Tibetan Plateau.”
From National Geographic: “Børge Ousland, now 54, teamed up with French adventurer Vincent Colliard, 30, for the Alpina Ice Legacy project. Over 10 years, the duo plans to ski across the world’s 20 largest glaciers in an effort to raise awareness about climate change. They crossed Alaska’s Stikine Glacier on their second expedition in May 2015, and in May 2016 they tackled the project’s third glacier, the St. Elias-Wrangell Mountains Range Ice Field. After 19 days and 267 miles in the field, [National Geographic] caught up with Ousland and Colliard in Alaska to talk suffering, partnership, and coming home alive.”
Roundup: Glacier-Fed Lakes, Remote Sensing, and Soil
Global Warming and Glacier-Fed Lakes
From Freshwater Biology: “Climate warming is accelerating the retreat of glaciers, and recently, many ‘new’ glacial turbid lakes have been created. In the course of time, the loss of the hydrological connectivity to a glacier causes, however, changes in their water turbidity (cloudiness) and turns these ecosystems into clear ones. To understand potential differences in the food-web structure between glacier-fed turbid and clear alpine lakes, we sampled ciliates (single-celled animals bearing ciliates), phyto-, bacterio- and zooplankton in one clear and one glacial turbid alpine lake, and measured key physicochemical parameters. In particular, we focused on the ciliate community and the potential drivers for their abundance distribution.”
Learn more about how global warming affects lakes here:
Glacier Remote Sensing Using Sentinel-2
From Remote Sensing: “Mapping of glacier extents from automated classification of optical satellite images has become a major application of the freely available images from Landsat. A widely applied method is based on segmented ratio images from a red and shortwave infrared band. With the now available data from Sentinel-2 (S2) and Landsat 8 (L8) there is high potential to further extend the existing time series (starting with Landsat 4/5 in 1982) and to considerably improve over previous capabilities, thanks to increased spatial resolution and dynamic range, a wider swath width and more frequent coverage.”
From Journal of Ecology: “Plant–soil interactions are temporally dynamic in ways that are important for the development of plant communities. Yet, during primary succession [colonization of plant life in a deglaciated landscape], the degree to which changing soil characteristics (e.g. increasing nutrient availabilities) and developing communities of soil biota influence plant growth and species turnover is not well understood. We conducted a two-phase glasshouse experiment with two native plant species and soils collected from three ages (early, mid- and late succession) of an actively developing glacial chronosequence ranging from approximately 5 to <100 years in age.”
Learn more about the impact of soil during glacier succession here:
Recent research has provided valuable information on glacier processes in the Hindu Kush Himalaya (HKH) mountains of South Asia, a region often called the “Third Pole” because it contains the largest area of ice outside the Arctic and Antarctic. Glacier retreat in this region has attracted considerable scientific and media attention. The 2007 Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) stated that Himalayan glaciers were shrinking faster than those in other parts of the world, and would likely be gone by the year 2035. This comment became controversial in 2009 because of its inaccuracy and weak basis in scientific research, and because glacier retreat in this region has major consequences for water supplies in one of the most densely-populated regions of the world. The IPCC made subsequent corrections in 2010.
This video from 2010, ‘Himalayan Glaciers Melting Faster Than Anywhere Else in World,’ conveys the tone of concern during the period of the controversy.
Stemming from this controversy, documenting the glacier coverage in the HKH has become a topic of critical importance. A recent study by Bajracharya et al. (2015) helps establish the extent of glacier coverage in the HKH region and the rate of glacier change in several basins in this region.
The rugged topography and the poor road networks in the HKH region have limited ground-based data collection. Remote sensing is therefore an attractive alternative. Bajracharya, a researcher at ICIMOD in Kathmandu, and his colleagues utilized satellite images, combining them in some cases with available ground-based data.
The study maps glacial coverage and retreat for a period extending from about 1980 (the precise date varies from location to location) through 2010. They map the decadal glacial change for the 1980s, 1990s and 2000s for four large representative basins which span the HKH region from west to east. The study basins are the Wakhan Corridor in Afghanistan, the Shyok Basin in Pakistan, the Imja Valley in Nepal, and the Lunana region in Bhutan. Glacier melt is a critical source of drinking and irrigation water for large populations in the regiona and critical to hydropower generation as well; glacial processes are also important because of the associated risks of glacier lake outburst floods (recap Imja Lake in Nepal).
So what can be learned from these newly assembled and analyzed data? First, the study reports, that despite the importance of glaciers in the HKH region, they cover only 1.4% of the region. In addition, it finds that glacier retreat is proceeding at different rates in different places. The most rapidly retreating glaciers are the ones located below 5000 m above sea level and the ones that are smallest in area. Combining these factors, the most impacted basin in the study is the Wakhan Corridor in Afghanistan.
The contributions of this study notwithstanding, scientific challenges in the HKH remain. The researchers note that there is continued uncertainty about glacier retreat and downstream impacts, because of uncertainties about future climate change and about the responses of glaciers to this change in this region, for which research remains incomplete. This study sets the stage for future research, looking to past data and suggesting directions of future work.
This prize-winning video from UNDP, the ‘Himalayan Meltdown,’ provides a thorough overview of the region and shows the need for ongoing research.
In 1994, an international group of scientists came together to form GLIMS (Global Land Ice Measurements from Space), a worldwide initiative to monitor and study glaciers using satellite data. For at least one hundred years, scientists had primarily used traditional field measurements to track glacier dynamics, but field data are by necessity limited in scope, and can be expensive and laborious to obtain.
The GLIMS team ultimately chose to use an imaging system called Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), jointly managed by NASA and Japan, for their glacier measurements. ASTER is installed aboard Terra, the flagship satellite of NASA’s Earth Observing System (EOS), which was launched in December 1999. ASTER data can be used to map land surface temperature, reflectance, and elevation, which allows the scientists to distinguish between glacier ice and snow and to measure changes in glacier volume.
Using digital images and data provided by ASTER, GLIMS created an up-to-the-minute database of the world’s glaciers, which includes ID, name, cross-references, and analysis of the state and dynamics of individual glaciers. In August 2014, GLIMS published their findings in book form: Global Land Ice Measurements from Space compiles these glacier profiles, provides a review of analysis methodologies for measuring changes in glacier volume, and offers predictions for future glacier change as well as some interpretations of potential impacts for policymakers in the context of climate change. The GLIMS scientists provide firm evidence that glaciers are shrinking worldwide, and they believe the cause is global warming.
The GLIMS book offers a basic theoretical background in glacier monitoring and mapping as well as remote sensing techniques. It also discusses measurements of glacier thinning from digital elevation models (DEMs), and calculation of surface flow velocities from satellite images. DEMs can provide specific data for every pixel in a satellite image, with a margin of error at 0.5m/year. Although cloud cover can interfere with accurate satellite data on glaciers, scientists are able to identify and discard this faulty data.
As described in the book, GLIMS scientists Siri Jodha Singh Khalsa and his colleagues have been able to assess the mass balance of alpine mountain glaciers by comparing historical topographic maps and DEMs derived from ASTER. For instance, they built a model and limited the error in the computation of mass balance from field measurements of China’s Sarytor glacier to less than 150mm/year.
Similarly, using techniques established by Dr. Todd Albert,who is also a member of GLIMS, a set of images of the Quelccaya Ice Cap spanning four decades was analyzed to create a history of ice surface area. Overall, Albert found that the ice cap has retreated from 58.9 km2 in 1975 to 40.8 km2 in 2010, with a loss of surface area of 31%. This history matches what has been observed in the field by glaciologists Lonnie Thompson and Henry Brecher since the 1970s.
Thanks to GLIMS, the rate of glacier melting can be measured and documented more precisely, providing readers with potential evidence of climate change. The GLIMS data provides solid support for future scientific research and planning in the face of climate change.
For other stories on the measurement of glaciers, look here.
“The Ossoue glacier in the Vignemale massif (3,298 m) is currently the longest and second largest of the Pyrenees (1,400-m length, 50-ha area), and the only one presenting glacier tongue morphology. We describe 50 MHz ground penetrating radar (GPR) and laser scanner surveys from which we assess the current state and dynamics of the glacier. ”
“It’s important to know two things about the adventure that followed, which Benuzzi chronicled in his book, “No Picnic on Mount Kenya.” First, Benuzzi did manage to escape the camp and climb to the summit of the mountain’s third-highest peak. Second, when Benuzzi came back down, after 18 days on the mountain, he apparently felt so rejuvenated — as if he had absorbed enough beauty to sustain him — that he decided to sneak back into the camp and picked up his life again as a prisoner. The mountain was that large and impressive, that sublime. ”