Posts Tagged "glacier retreat"

Research Shows How Climate Change Drives Glacier Retreat

Posted by on Feb 21, 2017 in All Posts, Featured Posts, Science | 0 comments

Research Shows How Climate Change Drives Glacier Retreat

Spread the News:ShareShrinking glaciers are oft-cited examples of the effects of anthropogenic climate change, providing dramatic imagery in different parts of the world. However, this has mostly been based on global aggregates of glacier extent. Differing opinions also exist about the best way to measure glacial change all over the world.  A recent study by Roe et al., published in Nature Geoscience, confirms that climate change has contributed to the shortening of numerous glaciers around the world, but the study is not immune to controversy surroundings the methods used. Using a combination of meteorological data and observations of glacier length, Roe et al. studied the influence of climate on 37 glaciers between 1880 and 2010. The glaciers were selected based on the continuity of length observations and the need for a wide geographical distribution. Glacier mass-balance records are a more direct measure of the effect of climate than glacier length as they measure the difference between the accumulation and ablation (sublimation or melting) of glacier ice. However, most mass-balance records do not extend for more than two decades, contributing to the previous lack of confirmation of the effect of climate change on individual glaciers around the world. The use of observations of glacier length helped to overcome this obstacle, but challenges were still encountered in obtaining long, continuous data sets, particularly for regions such as Asia and South America. In conversation with GlacierHub, Roe shared that many factors can affect the availability of continuous data sets. “For example, the collapse of the Soviet Union led to many glacier observation programs being abandoned,” he stated. An additional challenge arose from the variation in conditions experienced by each glacier. “Every glacier is a unique product of its local climate and landscape,” Roe shared, citing the example of maritime glaciers, which typically experience a large degree of wintertime accumulation variability. “This can mask the signal of a warming that, so far, has mainly impacted the summertime mass balance,” he added. Nevertheless, Roe et al. found that there was at least a 99% chance that a change in climate was needed to account for the retreat of 21 of the glaciers studied. “Even for the least statistically significant (Rabots Glacier in Sweden), there was still an 89% chance that its retreat required a climate change,” Roe said. As glaciers tend to have decadal responses to changes in climate, their retreat since 1880 is likely to be a result of twentieth-century temperature trends. They also act as amplifiers of local climate trends, providing strong signal-to-noise ratios that serve as strong evidence for the effects of anthropogenic climate change. For example, one of the glaciers included in the study, Hintereisferner in the Austrian Alps, retreated 2,800m since 1880, with a standard deviation (a measure of the deviation of values from the mean) of 130m. This value is small compared to the amount of retreat, providing a strong signal of change. “We hope that these results will lead to a stronger scientific consensus about the cause of glacier retreat. The last round of the Intergovernmental Panel on Climate Change was quite timid, concluding only that it was ‘likely’ that a ‘substantial’ part of glacier retreat was due to human-caused climate change,” Roe added. IPCC nomenclature would make it “very likely” (≥90%) that all but one of the glaciers in this study have retreated because of climate change, allowing for stronger conclusions to be drawn. Excitement about the results of this study was shared by Joerg Schaefer, professor at the Lamont-Doherty Earth Observatory: “Under Roe’s lead, the really smart glacier people find ways to explain this strange...

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Ion Concentrations Are Growing in Himalayan Lakes

Posted by on Oct 25, 2016 in All Posts, Featured Posts, Science | 1 comment

Ion Concentrations Are Growing in Himalayan Lakes

Spread the News:ShareDr. Franco Salerno and a team of Italian researchers conducted long-term field work in the Himalayan area, discovering a dramatic increase of ionic concentrations in glacial lakes. This increase may lead to some large and irreversible environmental effects, according to Salerno et al. A report detailing their findings was published in the journal of Environmental Science & Technology in July. Over the past two decades, Dr. Salerno and his team have observed a significant rise in ionic content in a total of 20 remote high-altitude glacial lakes located in central southern Himalaya. When asked by GlacierHub about why his team conducted their research in the Himalayan region, Dr. Salerno said, “The Italians have a long experience and passion for the high mountains. The culture and the capacity to climb is probably born around the Alps, and also drove us to study the Himalayan glaciers.” The group had to overcome many difficulties to perform their research including low temperatures, language barriers, and even snowblindness. But thanks to help from the local people, they managed to finish their research. The scientists also received support from the Ev-K2-CNR Association and the Italian National Research Council (CNR) to conduct studies in the Hindu Kush – Karakorum – Himalaya region and the countries of Nepal, Pakistan, China (Tibetan Autonomous Region) and India. Among their findings, the team detected a substantial rise of in-lake chemistry determined mainly by the sulfate concentration. LCN9, one of the 20 lakes monitored on an annual basis for the last 20 years, was found to have sulfate concentrations that increased by over 4-fold over that time period. In this region, the researchers also observed a significant relationship between the increase in the annual temperature recorded in the area and the enhanced conductivity in two glacial lakes. After examining several factors, including temperature, precipitation, rocks and soil weathering processes, and seasonal snow cover duration, they concluded that glacier retreat likely was the main factor responsible for the observed increase of sulfate concentrations. Moreover, the weakened monsoon of the past two decades has partially contributed to the lakes’ enrichment through runoff waters that are concentrated in solutes and by lowering the water table, resulting in more rock exposed to air and enhanced mineral oxidation. The higher mineral contents have not threatened the ecosystems, but high mountain ecosystems can be especially vulnerable to climate change. The change may lead to some negative outcomes not yet foreseen. Research in other areas including the Florida Everglades, California Limekiln Creek and Vestfold Hills have shown the negative impacts of increased sulfate concentrations on lake ecosystems. By the same token, a notable increase of ionic concentrations may lead to irreversible changes to the fragile local ecosystem, biodiversity in the lakes or even human health. As Dr. Salerno commented, “We think that the glacier masses in this region are decreasing as coupled effect of the global warming and the weakness of the monsoon. Even if these changes do not pose a direct and immediate threat to the ecosystem, they occurred in a limited time span and significantly modified the average chemical composition of lake water, which will cause some potential changes in the future.”   Spread the...

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Roundup: Porcupine Glacier, Patterned Ground and Ciliates

Posted by on Oct 24, 2016 in All Posts, Featured Posts, Roundup | 0 comments

Roundup: Porcupine Glacier, Patterned Ground and Ciliates

Spread the News:ShareRoundup: Glacier Calving, Ciliates and the Alps   A calving event in Porcupine Glacier shows rapid retreat From the American Geophysical Union: “Porcupine Glacier is a 20 km long outlet glacier of an icefield in the Hoodoo Mountains of Northern British Columbia that terminates in an expanding proglacial lake. During 2016 the glacier had a 1.2 square kilometer iceberg break off, leading to a retreat of 1.7 km in one year. This is an unusually large iceberg to calve off in a proglacial lake, the largest ever seen in British Columbia or Alaska… The retreat of this glacier is similar to a number of other glaciers in the area: Great Glacier, Chickamin Glacier, South Sawyer Glacier and Bromley Glacier. The retreat is driven by an increase in snowline/equilibrium line elevations which in 2016 is at 1700 m, similar to that on South Sawyer Glacier in 2016.” Learn more about the retreat of Porcupine glacier, and view satellite images here.   Patterned ground exposed by glacier retreat in the Alps From the Biology and Fertility of Soils: “Patterned ground (PG) is one of the most evident expressions of cryogenic processes affecting periglacial soils, where macroscopic, repeated variations in soil morphology seem to be associated with small-scale edaphic [impacted by soil] and vegetation gradients, potentially influencing also microbial communities. While for high-latitude environments only few studies on PG microbiology are available, the alpine context, where PG features are rarer, is almost unexplored under this point of view… These first results support the hypothesis that microbial ecology in alpine, periglacial ecosystems is driven by a complex series of environmental factors, such as lithology [study of the general physical characteristics of rocks], altitude, and cryogenic activity, acting simultaneously on community shaping both in terms of diversity and abundance.” Learn more about glacier retreat in the Italian Alps here.   Microorganisms found in glacial meltwater streams From Polar Biology: “Microbial communities living in microbial mats are known to constitute early indicators of ecosystem disturbance, but little is known about their response to environmental factors in the Antarctic. This paper presents the first major study on ciliates [single-celled animals bearing cilia] from microbial mats in streams on King George Island (Antarctica)… Samples of microbial mats for ciliate analysis were collected from three streams fed by Ecology Glacier. The species richness, abundance, and biomass of ciliates differed significantly between the stations studied, with the lowest numbers in the middle course of the stream and the highest numbers in the microhabitats closest to the glacier and at the site where the stream empties into the pond. Variables that significantly explained the variance in ciliate communities in the transects investigated were total organic carbon, total nitrogen, temperature, dissolved oxygen, and conductivity.” Learn more about the ciliates here. Spread the...

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Roundup: River Outlets, Plant Habitats, and Village Partners

Posted by on Oct 10, 2016 in All Posts, Featured Posts, Roundup | 0 comments

Roundup: River Outlets, Plant Habitats, and Village Partners

Spread the News:ShareRoundup: Canadian River Vanishes, Plants in the Himalayas and Pakistan’s Villages Glacier retreat in Canada causes Yukon river to vanish. From CBCNews: “It’s been the main source of water into Yukon’s Kluane Lake for centuries, but now the Slims River has suddenly slimmed down — to nothing. ‘What folks have noticed this spring is that it’s essentially dried up,” said Jeff Bond of the Yukon Geological Survey. ‘That’s the first time that’s happened, as far as we know, in the last 350 years.’ What’s happened is some basic glacier hydrology, Bond says — essentially, the Kaskawulsh Glacier has retreated to the point where its melt water is now going in a completely different direction, away from the Slims Valley. Instead of flowing north 19 kilometres from the glacier’s toe into Kluane Lake (and ultimately, the Bering Sea), that melt water is now draining eastward via the Kaskawulsh River towards the Pacific Ocean off the Alaska panhandle. It’s a reminder that glacier-caused change is not always glacial-paced.” Read more about the effects of glacier retreat on the Slims River here:   The world’s highest vascular plants found in Indian Himalayas. From Microbial Ecology: “Upward migration of plants to barren [just below the snowl areas is occurring worldwide due to raising ambient temperatures and glacial recession. In summer 2012, the presence of six vascular plants, growing in a single patch, was recorded at an unprecedented elevation of 6150 m.a.s.l. close to the summit of Mount Shukule II in the Western Himalayas (Ladakh, India). Whilst showing multiple signs of stress, all plants have managed to establish stable growth and persist for several years.” Learn more about the role of microbes in the process of plant upward migration here.   Local struggles in Pakistan show adaptations to glacier thinning. From Erdkunde: “Framing adaptation as a process of assemblage-building of heterogeneous human and non-human [actors], two village case studies are investigated where glacier thinning has dried up a source of irrigation water, turning cropland into desert. While in the first case case, villagers were able to construct a new and extraordinary water supply scheme with the help of external development agencies, in the second case, several approaches to utilize alternative water sources over three decades were unsuccessful. An account of the adaptation assemblages shows how a diversity of actants such as individual leaders, community, external agencies, construction materials, landslides and geomorphological features play variable and contingent roles in the success or failure of adaptation efforts, thus co-defining their outcome in complex ways.” Learn more about the adaption efforts to glacier thinning in northern Pakistan here. Spread the...

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Could Glacier Retreat Cause Seals to Wander?

Posted by on Jan 19, 2016 in All Posts, Featured Posts, Science, Uncategorized | 0 comments

Could Glacier Retreat Cause Seals to Wander?

Spread the News:ShareThough populations of harbor seals – the captivating species seen in almost every zoo – are stable in other areas of the world, they are seeing declines in southeastern Alaska. These particular seals use icebergs calved from nearby glaciers as a place to rest and breed, but changes in ice availability are affecting these behaviors, crucial to their survival and reproduction. Two separate studies, one by the National Park Service (NPS) and one by the Alaska Department of Fish and Game (ADFG), have independently found that seals may be changing their distribution and behavior to match the shifting locations of ice, as glaciers retreat. Jamie Womble, leading the NPS research in Glacier Bay, is providing a new way of relating glacier ice extent and harbor seal territory, both in location and seasonality. Womble and her team aim to find the exact distribution and movements of these Alaskan harbor seals. Aerial tracking– flying above the ice and counting the seals–is a method that works effectively in the region. They also glue GPS transmitters to the seals, and track their movements on land-based monitors. These transmitters come off safely during the next summer’s molt, so they present only minimal risk to the animals. Womble and her team found that “[d]espite extensive migration and movements of seals away from Glacier Bay during the post-breeding season, there was a high degree of inter-annual site fidelity (return rate) of seals to Glacier Bay the following pupping/breeding season.” In addition to studying the distances which the seals traveled, Womble and her group also examined the patterns of seal movement in relation to the glacial ice. The team studied the ice distribution within John Hopkins Inlet, which they coordinated with aerial tracking data to examine the relationship between the ice extent and the harbor seals. John Hopkins Inlet, the main area of research for Womble, is home to Johns Hopkins Glacier and Gilman Glacier which are among the few advancing glaciers in this region. Seals were found to congregate in areas with the highest percentage of ice. “Tidewater glacier fjords in Alaska host some of the largest seasonal aggregations of harbor seals in Alaska,” Womble told GlacierHub in an interview. Many of these tidewater glaciers – glaciers that run into the sea and calve frequent icebergs – are thinning, and a few have begun retreating. In particular, rapid retreat on the east side of Glacier Bay is leading to decreased seal pupping. During this critical season when the pups are newborn, mother seals and the weaning baby seals use flat icebergs to rest. “By 2008, no seals were pupping in Muir Inlet, and fewer than 200 seals were counted in McBride Inlet near the terminus of the McBride Glacier, the only remaining tidewater glacier in the East Arm of Glacier Bay,“ the NPS team stated in a recent report. In a report, ADFG  emphasizes the importance of  studying  “…why, how, and when harbor seals use glacial habitat, and whether the rapid thinning and retreat of Alaskan glaciers associated with climate change could negatively affect harbor seals…” Their research documented similar instances of glacier thinning and retreat and they are also monitoring seal movement, as well as other topics, including seal diet, seal weight and bodily composition and disturbances by tour vessels. Though ADFG began their work in Glacier Bay, the same site as the other team, they moved their research to Tracy Arm Ford’s Terror Wilderness Area – more than 200 miles to the southeast. The ADFG team has attached transmitters such as SPOT  to track the seals. These beam data on location, heart rate and other biological indicators up to satellites. To gather data, the researchers depend on the seals surfacing to breathe or rest, since the satellites cannot receive signals that are released underwater....

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