Category: climate change glacier retreat

World Glacier Monitoring Service 30th Anniversary

On By mspeltoIn climate change glacier retreat, glacier climate change, Glacier Observations

Zemp_20160831-25

The numbers on the left y-axis depict quantities of glacial mass loss from the WGMS and sea level rise, and the suns across the horizon contain numbers that represent the global increase in temperature, coinciding with the timeline on the lower x-axis From Jill Pelto

The World Glacier Monitoring Service (WGMS) celebrated 30 years of achievement last week. I have had the privilege of being the United States representative to the WGMS and was an invited speaker for the Jubilee held in Zurich, Switzerland along with Matthias Huss, Wilfried Haeberli, Liss Marie Andreassen and Irene Kopelman. This post examines the important role that WGMS has and continues to serve under the leadership of Michael Zemp. The organization has been compiling, homogenizing and publishing data on glacier fluctuations and mass balance primarily from 1986-2013. WGMS remains the leading organization for the collection, storage and dissemination of information on the fluctuations of alpine glaciers. The resulting standardized collection of alpine glacier data that is archived by WGMS, is also leading to analysis efforts that otherwise would be hampered by limited data and lack of homogeneity to the data. Glaciers are recognized as one of the best climate indicators.  Mass balance data is the best parameter to measure on glaciers for identifying climate change, because of its annual resolution. The core of the WGMS data set has been frontal variations, which indicate longer response to climate as well as dynamic changes.  The key data set today provided by WGMS are the reference glaciers.

This set of glaciers has a 30-year continuous record of annual mass balance measured in the field, and each glacier also has geodetic verification.  This mass balance data set is featured on the Global Climate Dashboard at NOAA. I report the mass balance of two reference glaciers Lemon Creek Glacier in Alaska and Columbia Glacier in Washington.  Today the field based work is being increasingly supplemented and supplanted by remote sensing methods.  This data sets indicates a period of sustained mass balance loss, and glacier retreat that Zemp et al (2015) using WGMS data noted as historically unprecedented.  The most recent compilation publication is the Global Glacier Change Bulletin.

This data set is of particular value during this period of climate change and is already chronicling the disapperance of a number of glaciers in the data set. Glacier loss is not a process that has been well documented. The WGMS data set can be enriched by more data from expanding monitoring, reporting data from archives and simply adding the submission of data as a step in the research process for those monitoring alpine glaciers. The video of my presentation looking at 33 consecutive years of field work and sharing this data after compilation with the WGMS is below. The slides below are from the Jubilee presentations.

 

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Kronotsky Peninsula, Kamchatka Glacier Fragmentation/Retreat

On By mspeltoIn climate change glacier retreat, russia glacier retreat

kamtchatka ge

The Kronotsky Peninsula is on the east coast of Kamchatka and has an small concentration of alpine glaciers.  A recent paper by Lynch et al (2016) indicates a significant recession during the start of the 21st century in Kamchatka.  They note a 24% loss in area, leading to fragmentation and an increase in the number of ice masses that could be considered glaciers.  Lynch et al (2016)  further note that the primary climate change has been a recent significant rise in summer temperature.  It is interesting how few and small the glaciers are in Kamchatka versus similar latitudes of Alaska.

kronotsky compare

The red arrows indicate the 2000 terminus position.  Purple arrows indicate areas of bedrock expansion within the 2000 glacier region.  Google Earth image is same 2013 image. 

A comparison of 2000 and 2015 Landsat images indicates the retreat of several glaciers and the expansion of bedrock glaciers within the previous accumulation zone areas. The snowcovered area in Sept. of 2000 is 35%, in Sept. 2015 the snowcovered area is 15%.  Summer temperature anomalies for Kamchatka have been high in June and July of 2016 (NOAA, 2016).  The result is that in August, 2016 despite the cloud cover it is evident that snowcover is less than 10% with time left in the melt season. September is one of the least cloudy months and if better imagery becomes available I will update this image here. The elevation of the glaciers is 2400-3700 m, relatively high. The termini of all three glaciers have retreated 200-400 m, which given the short time span and small size of the glaciers is significant. The lack of retained snowcover in recent years indicates that these glaciers lack a persistent accumulation zone and cannot survive (Pelto, 2010). A closeup of the terminus of the glaciers indicate all have low slopes, limited crevassing, and are poised more further retreat.  Of the three termini the southern one indicates a recsssional moraine set (R). The western glacier concentric crevasses that indicate subsidence of terminus area (C).  The northern glacier has significant supraglacial stream channels that took multiple years to develop, indicative of limited development (B).

kamchatka 2016

2016 Landsat image of Krontosky Peninsula Glaciers

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Glaciers in BAMS State of Climate 2015

On By mspeltoIn climate change glacier retreat, glacier climate change, Glacier Observations

Decrease in Glacier Mass Balance uses measurements from 1980-2014 of the average mass balance for a group of North Cascade, WA glaciers. Mass balance is the annual budget for the glaciers: total snow accumulation minus total snow ablation. Not only are mass balances consistently negative, they are also continually decreasing. Glaciers have been one of the key and most iconic examples of the impact of global warming.  

BAMS State of Climate 2015 asked me about featuring some of the glacier images for the cover, and I countered with a suggestion to utilize one of a series of paintings by Jill Pelto that illustrate the impact of climate change magnifying the impact of the data.  Below are sections of this years report that focus on glaciers.

Glaciers and ice caps (outside Greenland)

M. Sharp, G. Wolken, L.M Andreassen, A. Arendt, D. Burgess, J.G. Cogley, L. Copland, J. Kohler, S. O’Neel, M. Pelto, L.Thompson, and B. Wouters

Among the seven glaciers for which 2014-2015 annual mass balance have been reported, the mass balances of glaciers in Alaska and Svalbard (three each) were negative, while the balance for Engabreen Glacier in Norway was positive. The pattern of negative balances in Alaska and Svalbard is also captured in time series of regional total stored water estimates, derived using GRACE satellite gravimetry, which are a proxy for regional total mass balance (ΔM) for the heavily glacierized regions of the Arctic (Figure 3). Measurements of ΔM in 2014-2015 for all the glaciers and ice caps in Arctic Canada and the Russian Arctic also show a negative mass balance year. The GRACE-derived time series clearly show a continuation of negative trends in ΔM for all measured regions in the Arctic. These measurements of mass balance and ΔM are consistent with anomalously warm (up to +1.5ºC) summer air temperatures over Alaska, Arctic Canada, the Russian Arctic, and Svalbard in 2015, and anomalously cool temperatures in northern Scandinavia, particularly in early summer (up to -2ºC). The warmer temperatures led to higher snowlines in the aforementioned regions as seen in images below.

clephane bay compare

Baffin Island Ice Cap near Clephane Bay indicate limited snowpack in 2015

frostisen compare

Frostisen Ice Cap, Svalbard with limited 2015 snowpack.

Alpine Glaciers

M.Pelto

Preliminary data for 2015 from 16 nations with more than one reporting glacier from Argentina, Austria, Canada, Chile, Italy, Kyrgyzstan, Norway, Switzerland, and United States indicate that 2015 will be the 32nd consecutive year of negative annual balances with a mean loss of -1169 mm for 33 reporting reference glaciers and -1481 mm for all 59 reporting glaciers. The number of reporting reference glaciers is 90% of the total whereas only 50% of all glaciers that will report have submitted data thusfar. The 2015 mass balance will likely be comparable to 2003, the most negative year at -1268 mm for reference glaciers and -1198 mm for all glaciers.

The cumulative mass balance loss from 1980-2015 is 18.8 m, the equivalent of cutting a 20.5 m thick slice off the top of the average glacier (Figure 1).  The trend is remarkably consistent from region to region (WGMS, 2015).  The decadal mean annual mass balance was -261 mm in the 1980’s, -386 mm in the 1990’s, –727 mm for 2000’s and -818 mm from 2010-2015.  The declining mass balance trend during a period of retreat indicates alpine glaciers are not approaching equilibrium and retreat will continue to be the dominant terminus response (Zemp et al., 2015). The recent rapid retreat and prolonged negative balances has led to many glaciers disappearing and others fragmenting (Pelto, 2010; Carturan et al, 2015).

columbia compare

In South America seven glaciers in Columbia, Argentina and Chile reported mass balance. All seven glaciers had losses greater than 1200 mm, with a mean of -2200 mm.  These Andes glaciers span 58 degrees of latitude.

In the European Alps, mass balance has been reported for 14 glaciers from Austria, France, Italy and Switzerland.  All 14 had negative balances exceeding 1000 mm, with a mean of -1865 mm. This is an exceptionally negative mass balance rivaling 2003 when average losses exceeded -2000 mm.

In Norway mass balance was reported for six glaciers in 2015, all six were positive with a mean of 780 mm.  This is the only region that had a positive balance for the year. In Svalbard six glaciers reported mass balances, with all six having a negative mass balance averaging -675 mm.

In Alberta, British Columbia, Washington and Alaska mass balance data from 17 glaciers was reported with a mean loss of -2590 mm, with all 17 being negative. This is the most negative mass balance for the region during the period of record.  From Alaska south through British Columbia to Washington the accumulation season temperature was exceptional with the mean for November-April being the highest observed.

In the high mountains of central Asia six glaciers from Russia, Kazakhstan, and Kyrgyzstan reported data, all were negative with a mean of -660 mm.

Columbia Glacier having lost nearly all of its snowcover by early August had its most negative mass balance of any years since measurements began in 1984

Thirty-third Annual North Cascade Glacier Climate Project Field Season Underway

On By mspeltoIn climate change glacier retreat, glacier climate change, Glacier Observations, glaciers salmon, North Cascade Glaciers4 Comments

fig8-1
Base Map of the region showing main study glaciers, produced by Ben Pelto.

From President Reagan to President Obama each August since 1984 I have headed to the North Cascade Range of Washington to measure the response of glaciers to climate change.  Specifically we will measure the mass balance of nine glaciers, runoff from three glaciers and map the terminus change on 12 glaciers. The data is reported to the World Glacier Monitoring Service.  Three glaciers that we have monitored annually have disappeared since 1984.

In 2016 for Mount Baker, Washington the freezing level from January-April was not as high as the record from 2015, but still was 400 m above the long term mean. The snowpack on June 1st was three weeks behind last year’s record melt, but still three to four weeks of head of normal. July has been exceptionally cool reducing this gap. With all the snow measurement stations losing snowcover by July 1, the gap is uncertain until we arrive on the glaciers. This will not be a good year, but will be a significant improvement over last year, likely more in the 2012 or 2013 category.  Each location is accessed by backpacking in and camping in tents.

We will first travel north to Mount Baker and the Easton Glacier, we will be joined by Oliver Lazenby, Point Roberts Press.  We will then circle to the north side where I expect we will be joined by Jezra Beaulieu and Oliver Grah, Nooksack Indian Tribe.  Jen Lennon from the Sauk-Suiattle Tribe and Pete Durr, Mount Baker Ski Patrol are also planning to join us here.   When we head into Columbia Glacier Taryn Black from U of Washington will join us. The field team consists of Mauri Pelto, 33rd year, Jill Pelto, UMaine for the 8th year, Megan Pelto, 2nd year, and Andrew Hollyday, Middlebury College.  Tom Hammond, 13th year will join us for a selected period.

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Aug.   1:  Hike into Easton Glacier.
Aug.   2:  Easton Glacier
Aug.   3:  Easton Glacier
Aug.   4:  Hike Out Easton Glacier, Hike in Ptarmigan Ridge
Aug.   5:  Sholes Glacier
Aug.   6:  Rainbow Glacier
Aug.   7:  Sholes Glacier and/or Rainbow Glacier
Aug.   8:  Hike out and into Lower Curtis Glacier
Aug.   9:  Lower Curtis Glacier
Aug. 10: Hike out Lower Curtis Glacier- Hike in Blanca Lake Mail Pickup Maple Falls, WA 98266
Aug. 11:  Hike in Columbia Glacier
Aug. 12:  Columbia Glacier
Aug. 13:  Hike out Columbia Glacier; Hike in Mount Daniels
Aug. 14:  Daniels and Lynch Glacier
Aug. 15:  Ice Worm Glacier
Aug. 16:  Ice Worm Glacier, Hike out Mount Daniels-Hike out

Sater Glacier, Alaska Not Retaining Snowcover

On By mspeltoIn alaska glacier retreat, climate change glacier retreat

sater glacier ge
2012 Google Earth Image. Purple arrows indicate areas where the margin is receding well above the lowest terminus.

Sater Glacier is in the Okpilak River watershed of the Brooks Range, Alaska. It is named for John Sater an early geologist working in the Brooks Range and on the nearby McCall Glacier. Here we examine Landsat imagery from 1987-2016 to identify changes in the glacier. Matt Nolan, U. Alaska-Fairbanks,  has provided links to the recent research and publications at McCall Glacier. These glacier have suffered increased mass loss since 1990 as a result of an increase in the equilibrium line altitude that has reduced accumulation area and is indicative of increased ablation (Delcourt al , 2008) as noted at Slender Glacier.

In 1987 Sater Glacier extended from 2300 m to 1600 m with two main tributaries joining 1 km above the terminus. Retained snowcover blankets most of the glacier in this early August image.  In 1995 the main change is the lack of retained snowcover on the glacier, with a month left in the melt season.  The retained snowcover is the accumulation area ratio (AAR), which needs to be above 50% for a glacier to be in equilibrium, but is less than 10% in 1995. The 2012 Google Earth image above indicates very little retained snowcover on the glacier in mid-July, AAR of 15%. Likely no retained snowcover by summer’s end. In 2015 a late July image again indicates limited retained snowcover, the AAR less than 10%.  In 2016 the late July image again indicates limited snowcover though slightly better than in 2015 with an AAR of 25%. This persistent failure to retain snowcover indicates a glacier than cannot survive (Pelto, 2010).  This has also led to the near separation of the tributaries, retreat of the upper margins of the glacier and terminus retreat of 250 m. The retreat of the terminus has been much less than Okpilak Glacier, but the prognosis due to the lack of retained snowcover is much worse, it cannot survive current climate.

sater glacier 1987
1987 Landsat image red arrow indicates 1987 terminus, yellow arrow 2015 terminus and purple arrows upglacier thinning.

sater glacier 1995
1995 Landsat image red arrow indicates 1987 terminus, yellow arrow 2015 terminus and purple arrows upglacier thinning.

sater glacier 2015
2015 Landsat image red arrow indicates 1987 terminus, yellow arrow 2015 terminus and purple arrows upglacier thinning.
sater 2016

2016 Landsat image red arrow indicates 1987 terminus, yellow arrow 2015 terminus and purple arrows upglacier thinning.

Sjögren Glacier Fast Flow, Fast Retreat, Antarctica

On By mspeltoIn Antarctic Glacier retreat, climate change glacier retreat, glacier climate change1 Comment

sjogren compare

Sjögren Glacier comparison in Landsat images from 2001 and 2016, red dots indicate terminus position, Point A, B, C and D are in fixed locations. 

Sjögren Glacier flows east from the northern Antarctic Peninsula and prior to the 1980’s was a principal feeder glacier to Prince Gustav Ice Shelf.  This 1600 square kilometer ice shelf disintegrated in the mid-1990’s and was gone in 1995 (Cook and Vaughan, 2010). Scambos et al (2014) noted a widespread thinning and retreat of Northern Antarctic Peninsula Glaciers with the greatest changes where ice shelf collapse had occurred, Sjögren Glacier being one of the locations. Scambos et al (2004) first documented the acceleration of glaciers that fed an ice shelf after ice shelf loss in the Larsen B region. A new paper by Seehaus et al (2016)  focuses on long term velocity change at Sjögren Glacier as it continues to retreat.  This study illustrates the acceleration is long lived with a peak velocity of 2.8 m/day in 2007 declining to 1.4 m/day in 2014, compared to a 1996 velocity of  0.7 m/day, which was likely already higher than the velocity in years prior to ice shelf breakup. Here we examine Landsat images from 1990, 2001, 2005 and 2016 to illustrate changes in terminus position of Sjögren Glacier

In the 1990 Landsat image Sjögren Glacier feed directly into the Prince Gustav ice Shelf which then By 1993 Seehaus et al (2016) note that Sjögren Glacier had retreated to the mouth of Sjögren Inlet in 1993, this is marked Point A on Landsat Images. By 2001 the glacier had retreated to Point B,  a distance of 7 km.  Between 2001 and 2005 Sjögren Glacier retreat led to a separation from Boydell Glacier at Point C.  In 2016 Sjögren Glacier had retreated 10-11 km from the 2001 location, and 4.5 km from Point C up the expanding fjord. The production of icebergs remains heavy and the inlet does not narrow for another 6 km from the front.  Seehaus et al (2016) Figure 1  indicates that the area of high velocity over 1 m/day extends 1 km upglacier, with somewhat of a slowdown at 6 km behind the front. The high velocity and limited change in fjord width in the lower 6 km indicates there is not a new pinning point to slow retreat appreciably in this stretch. Figure 1 also illustrates the retreat from 1993-2014. The pattern of ice shelf loss and glacier retreat after loss has also played out at Jones Ice Shelf and Rohss Bay.

sjogren glacier 1990

1990 Landsat Image of Sjogren Glacier and Prince Gustav Ice Shelf, terminus marked by red dots

sjogren 2005

2005 Landsat Image of Sjogren Glacier, terminus marked by red dots

 

Chaupi Orko Glaciers, Bolivia Extensive Recession

On By mspeltoIn bolivia glacier retreat, climate change glacier retreat

chaupi orko compare

Landsat comparison of the Chaupi Orko Glaciers from 1988, 1999 and 2015.  Red arrows indicate 1988 terminus and yellow arrows the 2015 terminus location.

Chaupi Orko is a 6044 m Andean peak in the Cordillera Apolobamba on the Peru-Bolivia border with glaciers radiating from it summit.  Here we examine a pair of glaciers on the southern side of the mountain that drain into Laguna Suches, which is split by the Bolivia-Peru border. Laguna Suches is most known for placer gold mining. Glaciers in Bolivia have been experiencing substantial retreat during the last 40 years, such as at Nevada Cololo. The glaciers of the Apolobamba have lost 48% of their area from 1975-2006 (Hoffmann, 2012). Hoffmann and Weggenmann (2012) observed both the extensive retreat, new lake formation, and the potential problem of glacier lake outbursts in this region, which is part of the Apolobamba Integrated Natural Management Area. In a continuation of these studies an excellent study in review by Cook et al (2016) indicates a 43% decline in glacier area in the Cordillera Apolobamba from 1986 to 2014. They identified a total of 25 lakes with some risk of GLOF, though historic occurrences to date in the area are few. They further found an decrease in proglacial lakes in contact with glaciers during this period. The glaciers here are summer accumulation type with the ablation occurring during the dry season from May-October .

In 1988 the southwest Chaupi Orko Glacier (W), red arrow, does not have a proglacial lake at its terminus. The southern Chuapi Orko Glacier (S) ends adjacent to a small lake east of the terminus, red arrow. By 1999 a small proglacial lake has formed at the terminus of the southwest Chaupi Orko Glacier. The southern Chaupi Orko Glacier has receded 350 m. By 2015 the southwest Chaupi Orko Glacier (W) has retreated to the yellow arrow, with the proglacial lake having expanded to an area of 0.35-0.4 square kilometers. Retreat of the west glacier has ranged from 500 to 800 m. The southern Chaupi Orko Glacier has retreated 600 m exposing two new small proglacial lakes that it has since largely retreated from. The lakes are narrow and too small to be a Glacier lake outburst flood (GLOF) threat. This particular basin does not pose a GLOF threat with no substantial lake below the south glacier and only the small, apparently shallow lake below the west glacier.   A small island in the midst of the lake, suggests lake not very deep. The west glacier has a calving face enhancing retreat (IC).Neither glacier indicates significant thinning higher on the glacier, suggests limited melting.  This is a region of significant ablation via sublimation vs melting, which is not as efficient a process for mass loss and is enhanced during La Nina periods (Vuille et al, 2008). The reduction of glacier area does lead to declines in glacier runoff, which will have a more widespread impact.

chaupi orko esri

Small island amidst proglacial lake from the west glacier, also ice cliff noted.
Apolobamba ge

Google Earth image of the Chaupi Orco region.

Conducting Long Term Annual Glacier Monitoring

On By mspeltoIn climate change glacier retreat, glacier climate change, North Cascade Glaciers

2015 time lapse easton

Easton Glacier in 1990, 2003 and 2015 from same location. Below Painting by Jill Pelto of crevasse assessment using a camline.

camline

This is the story of how you develop and conduct a long term glacier monitoring program.  We have been monitoring the annual mass balance of Easton Glacier on Mount Baker, a stratovolcano in the North Cascade Range, Washington since 1990.  This is one of nine glaciers we are continuing to monitor, seven of which have a 32 year long record. The initial exploration done in the pre-internet days required visiting libraries to look at topographic maps and buying a guide book to trails for the area.  This was followed by actual letters, not much email then, to climbers who had explored the glacier in the past, for old photographs.  Armed with photographs and maps we then determined where to locate base camp and how to access the glacier.  The first year is always a test to make sure logistically you can reach enough of the glacier to actually complete the mass balance work with a sufficiently representative network of measurement sites.  The second test is if you can stand the access hike, campsite, and glacier navigation, to do this every year for decades; if the answer is no, move on.  That was the case on Boulder Glacier, also on Mount Baker:  poor trail conditions and savage bugs, were the primary issue. Next we return to the glacier at the same time each year, completing the same measurements each year averaging 210 measurements of snow depth or snow melt annually.  This occurs whether it is gorgeous and sunny, hot, cold, snowy, rainy, or recently on this glacier dealing with thunderstorms.  You wake up, have your oatmeal and coffee/cider/tea, and get to work.  Lunch on the snow features bagels, dried fruit, and trail mix. Happy hour features tang or hot chocolate depending on the weather.  It is then couscous, rice, pasta or quinoa for dinner, with some added dried vegetable or avocado.  The sun goes behind a mountain ridge and temperatures fall, and the tent is the haven until the sun returns.  Repeat this 130 times on this glacier and you have a 25 year record. During this period the glacier has lost 16.1 m of water equivalent thickness, almost 18 m of thickness.  For a glacier that averaged 70 m in thickness this is nearly 25% of the volume of the glacier gone.  The glacier has not maintained sufficient snow cover at the end of the summer to have a positive balance, this is the accumulation area ratio, note below.  The glacier has retreated 315 m from 1990-2015.  This data is reported annually to the World Glacier Monitoring Service.  The glacier has also slowed its movement as it has thinned, evidenced by a reduction in number of crevasses. During this time we have collaborated with researchers examining the ice worms, soil microbes/chemistry, and weather conditions on the ice. This glacier supplies runoff to Baker Lake and its associated hydropower projects.  Our annual measurements here and on Rainbow Glacier and Lower Curtis Glacier in the same watershed provide a direct assessment of the contribution of glaciers to Baker Lake.  The glacier is adjacent to Deming Glacier, which supplies water to Bellingham, WA. The Deming is too difficult to access, and we use the Easton Glacier to understand timing and magnitude of glacier runoff from Deming Glacier.

The glacier terminates at an elevation of 1650 m, but thinning and marginal retreat extends much higher.  A few areas of bedrock have begun to emerge from beneath the ice as high as 2200 m. The changes in ice thickness are minor above 2500 m, indicating this glacier can retreat to a new equilibrium point with current climate.

Mass balance, terminus and supra glacial stream assessment are illustrated in the video, Filmed by Mauri Pelto, Jill Pelto, Melanie Gajewski, with music from Scott Powers.

easton 2010
Mass balance Map in 2010 of Easton Glacier used in the field for reference in following years. 

easton aar

Accumulation Area Ratio/Mass balance relationship for Easton Glacier

Chutanjima Glacier Retreat & High Snowline, Tibet, China 1991-2015

On By mspeltoIn china glacier retreat, climate change glacier retreat, glacier climate change, Glacier Observations

mugunong glacier tibet compare

A comparison of three Tibet glaciers in 1988, 1991 and 2015 Landsat images. Red arrows are the 1988 terminus position, yellow arrow the 2015 terminus location and purple dots the snowline in late October 2015.  U=unnamed, CH=Chutanjima Glacier and MO=Mogunong Glacier: which did not retreat significantly and lacks a red arrow.

A recent European Space Agency Sentinel-2A image of southern Tibet, China and Sikkim illustrated three very similar glaciers extending north from the Himalayan divide on the China-India Border. We examine these three glacier in this post. The three glaciers all drain into the Pumqu River basin, which becomes the Arun River. The largest is unnamed the two easternmost are Chutanjima and Mogunong Glacier.The glaciers all have similar top elevations of 6100 -6200 m and terminus elevations of 5260-5280 m.  All three are summer accumulation type glaciers with most of the snow accumulating during the summer monsoon, though this is also the dominant melt period on the lower glacier.  Wang et al (2015) examined moraine dammed glacier lakes in Tibet and those that posed a hazard, none of the three here were identified as hazardous.  The number of glacier lakes in the Pumqu Basin has increased from 199 to 254 since the 1970’s with less than 10% deemed dangerous, but that still leaves a substantial and growing number (Che et al, 2014). Here we compare Landsat images from 1988, 1992  and 2015 to identify their response to climate change.   The second Chinese Glacier inventory (Wei et al. 2014) indicated a 21% loss in glacier area in this region from 1970 to 2009.The pattern of retreat and lake expansion is quite common as is evidenced by other area glaciers, such as Gelhaipuco, Thong Wuk, Baillang Glacier and Longbashaba Glacier.

In the 1988 image all three glaciers terminate at the southern end of a proglacial lake with seasonal lake ice cover, red arrows.  In 1991 the lakes are ice free and have some icebergs in them.  By 2015 the retreat has been 500 m for the easternmost glacier, 400 m for Chutanjima Glacier and 100 m at most for Mogunong Glacier. Each glacier has remained extensively crevassed to the terminus indicating they remain vigorous.  The retreat is greatest for the two ending in expanding lakes.  Mogunong Glacier appears to be near the upper limit of the lake, and is not calving, which likely led to less retreat. An icefall is apparent 700 m from the front of Mogunong Glacier.  The width of the glacier below this point has diminished considerably from 1988 to 2015, though retreat has been minor, indicating a negative mass balance.  There is an icefall 1 km from the icefront of Chutanjima, indicating the maximum length the lake would reach.

The Sentinel image indicates an important characteristic and trend in the region.  This is an early February image and the snowline is quite high on the glacier in the midst of winter.  The snowline is at 5850-5900 m nearly the same elevation as in late October of 2015 seen above. This illustrates the lack of winter accumulation that occurs on these summer accumulation glaciers.  It also indicates a trend toward ablation processes remaining active, though limited from November-February.  The lack of snowcover on the lower glaciers as the melt season begins hastens ablation zone thinning, mass balance loss and retreat.

mugunong glacier 2016

Europenan Space Agency, Sentinel-2A image from 1 February 2016. Orange arrow indicates icefalls and purple dots the snowline.

mogunong ge
2014 Google Earth image of the region. Orange arrows indicate icefalls, note the crevassing extending to glacier front.

Brady Glacier, Alaska 2016 Early Melt Season & Lake Expansion

On By mspeltoIn alaska glacier retreat, climate change glacier retreat, glacier climate change

brady lake compare 2016

Comparison of Brady Glacier in 1986 and 2016 Landsat images.  The snowline is similar in May 2016 and August 1986. Lakes noted are: A=Abyss, B=Bearhole, D=Dixon, N=North Deception, O=Oscar, Sd=South Dixon, Sp=Spur, T=Trick.

Brady Glacier,  is a large Alaskan tidewater glacier, in the Glacier Bay region that is beginning a period of substantial retreat Pelto et al (2013). In 2016 the melt season has been intense for the Brady Glacier in Alaska. Pelto et al (2013) noted that the end of season observed transient snowline averaged 725 m from 2003-2011, well above the 600 m that represents the equilibrium snowline elevation. On May 20, 2016 the transient snowline (TSL) is at 500 m. Typically the TSL reaches 500 m in early July: 7/13/2004=530; 7/8/2005=550, 7/3/2006=500, 7/22/2007=520, 7/3/2009=500; 7/10/2013=500. The high early season snowline is indicative of an early opening and filling of the many proglacial lakes that secondary termini of the glacier end in. The lakes Trick, North Deception, Dixon, Bearhole, Spur, Oscar, and Abyss continue to evolve. In addition two new lakes have developed. The changes are evident in a comparsion of 1986 and 2016 Landsat images. The TSL on May 20/2016 is remarkably similar to the August 20, 1986 TSL.
base figure

2010 Landsat image of the glacier indicating the 1948 margin in Orange and the 2016 margin in yellow. Lakes noted are: A=Abyss, B=Bearhole, D=Dixon, N=North Deception, O=Oscar, S=Spur, T=Trick.

There is a consistent pattern in the change in position of the glacier margin at each of the lakes between 1948 and 2010. The rate of retreat of the glacier margin at all seven lakes accelerated later during this period; the mean retreat rate is 13 m/a from 1948 to 2004 and 42 m/a  from 2004 to 2010 (Pelto et al, 2013). Lake area and calving fronts were measured for each lake: Spur, Abyss, North Deception, Bearhole, Oscar, and East Trick based on the September 2010 imagery, with earlier measurements from Capps et al. (2010). Lake areas have increased as a result of glacier retreat, and can decrease due to declines in surface water levels as previously ice-dammed conduits form to drain the lake. Lake water levels have fallen in Abyss, Bearhole, Dixon, North Deception, Spur, and Trick since 1948 Capps et al (2010). Only Oscar Lake, the most recent to form, has maintained its surface level. Retreat of the glacier margin has been greatest at Bearhole, North Deception Lake, and Oscar Lake, which as a consequence have expanded substantially in area. Lake water level declines at Abyss, Spur, and Trick have offset the increase in area resulting from glacier retreat, leading to small changes in lake area. The seven lakes have changed dramatically in response to this acceleration in retreat.

Trick Lakes: In 1986 North and South Trick Lake are proglacial lakes in contact with the glacier. By 2016 the two lakes are no longer in contact with the glacier, water levels have fallen and a third lake East Trick Lake has formed. The more recently developed East Trick Lake is the current proglacial Trick Lake, a large glacier river exits this lake and parallels the glacier to the main Brady Glacier terminus, going beneath the glacier for only several hundred meters.

trick 2014

2014 Google Earth image of Trick Lakes, and the glacier river exiting to the main terminus, purple arrows.

North Deception Lake had a limited area in 1986 with no location more than 500 m long. By 2016 retreat has expanded the lake to a length over 2 km. The width of the glacier margin at North Deception Lake will not change in the short term, but the valley widens 2 km back from the current calving front, thus the lake may grow considerably in the future.

South Dixon Lake This new lake does not have an official name. It did not exist in 1986, 2004, 2007 or 2010. It is nearly circular today and 400 m in diameter.

Dixon Lake: It is likely that retreat toward the main valley of the Brady Glacier will lead to increased water depths at Dixon Lake, observations of depth of this lake do not exist. Retreat from 1986 to 2016 has been 600 m.

Bearhole LakeBearhole Lake is expanding up valley with glacier retreat, and there are no significant changes in the width of the valley that would suggest a significant increase in calving width could occur in the near future. Currently the lake is 75 m deep at the calving front and there has been a 1400 m retreat since 1986 Capps et. al. (2013).

Spur Lake:It is likely that retreat toward the main valley of the Brady Glacier will lead to increased water depths at Spur Lake. the depth has fallen as the surface level fell from 1986-2016 as the margin retreated 600 m, leaving a trimline evident in the 2016 imagery.

Oscar Lake has experienced rapid growth with the collapse of the terminus tongue. Depth measurements indicate much of the calving front which has increased by an order of magnitude since 1986 is over 100 m. The tongue as seen in 2014 Google Earth image will continue to collapse and water depth should increase as well. The central narrow tongue has retreated less than 200 m since 1986, but the majority of the glacier front has retreated more than 1 km since 1986.

oscar 2014

Google Earth image of Oscar Lake, illustrating the number of large icebergs of this ongoing terminus collapse.

Abyss Lake: Continued retreat will lead to calving width expansion> The retreat from 1986 to 2016 has been 400 m. The water depth has been above 150 m at the calving front for sometime and should remain high.

Glacier thinning and retreat near the lakes dammed by Brady Glacier have led to changes in the widths of calving fronts between. The combined increase in the width of the six secondary calving fronts is 34% from 1948 to 2004, and 15% from 2004 to 2010 (Pelto et al, 2013) With the inclusion of South Dixon Lake and continued expansion of Dixon and Oscar Lake the calving width has continued to increase up to 2016. Calving widths at Bearhole Lake, Spur Lake, and Trick Lake will not change appreciably. Spur Lake and Trick Lake parallel the margin of the glacier, and although this margin will likely continue to recede, the length of the depression filled by the two lakes probably will not change.

Water depth is an important factor affecting the calving rate of glaciers in lacustrine environments; velocity and calving rate increase with water depth by a factor of 3.6 (Skvarca et al., 2002). Capps et. al. (2013) determined the bathymetry and calving depths of five of the lakes at Brady Glacier. Water depths increase toward the calving fronts at Abyss Lake, Bearhole Lake, Oscar Lake, and Trick Lake; only at North Deception Lake does the water not currently become deeper towards the calving front; however it almost certainly will as the east margin moves into the main Brady Glacier valley. The observations suggest that mean calving depths of proglacial lakes, at least in the short term, will increase with continued retreat. Increases in calving width and depth will lead to increased calving at the secondary termini in the near future (Pelto et al, 2013).

Bailang Glacier and Angge Glacier Retreat, China 1995-2015

On By mspeltoIn china glacier retreat, climate change glacier retreat, Himalaya glacier retreat

bailang compare

Comparison of 1995 and 2015 Landsat image illustrating 1995 (red arrows) and 2015 terminus locations (yellow arrows) of Bailang Glacier (B) and Angge Glacier (A).  Purple arrows indicate areas upglacier of expanding bedrock due to glacier thinning. Head of Chubda Glacier (C), Bhutan indicated. 

Bailang Glacier and Angge Glacier, China are adjacent to the Chubda Glacier, Bhutan.  Despite being in a different nation on a different side of the Himalaya, the behavior is the same. These are both summer accumulation type glaciers that end in proglacial lakes.  Both lakes are impounded by broad moraines that show no sign of instability for a potential glacier lake outburst flood. The number of glacier lakes in the adjacent Pumqu Basin to the west has increased from 199 to 254 since the 1970’s with less than 10% deemed dangerous  (Che et al, 2014) Here we compare Landsat images from 1995 and 2015 to identify their response to climate change.   The second Chinese Glacier inventory (Wei et al. 2014) indicated a 21% loss in glacier area in this region from 1970 to 2009.

Bailang Glacier in 1995 terminated in a proglacial lake that was 2.1 km long at an elevation of ~5170 m, red arrow. Angge Glacier terminated in a lake that was 1 km long at an elevation of ~5020 m.  By 2001 both glaciers had experienced minor retreat of less than 250 m.  By 2014 both lakes had expanded considerably due to retreat, no significant change in water level had occurred. By 2015 Bailang Glacier had retreated  800-900 m and the lake was now 3 km long.  A key tributary on the west side near the yellow arrow had also detached. There is no significant slope change in the lower 1 km of the glacier indicating retreat should continue enhanced by melting in and calving in the proglacial lake.  For Angge Glacier retreat from 1995 to 2015 was 700 to 800 m, with the glacier retreating to a westward bend in the lake basin.  The glacier has an icefall just above the current terminus suggesting the lake basin will soon end, which should slow retreat. The pattern of retreat and lake expansion is quite common as is evidence by Gelhaipuco, Thong Wuk and Longbashaba Glacier.

bailang glacier 2001

2001 Landsat image illustrating 1995 (red arrows) and 2015 terminus locations (yellow arrows) of Bailang Glacier (B) and Angge Glacier (A).  Head of Chubda Glacier (C), Bhutan indicated. 

bailang glacier 2014

2014 Landsat image illustrating 1995 (red arrows) and 2015 terminus locations (yellow arrows) of Bailang Glacier (B) and Angge Glacier (A).  Head of Chubda Glacier (C), Bhutan indicated. 

 

Chubda Glacier Retreat, Bhutan 1995-2015

On By mspeltoIn climate change glacier retreat, Himalaya glacier retreat

chubda glacier compare

Chubda Glacier comparison in 1995 and 2015 images.  Red arrow indicates 1995 terminus location and yellow arrow is 2015 terminus location.  Pink arrows indicate areas upglacier of expanding bedrock. Green arrow indicates moraine areas amidst the lake.  The orange arrow indicates a secondary glacier.

Chubda Glacier, Bhutan drains south from Chura Kang on the Bhutan/China border.  The glacier terminates in Chubda Tsho, a glacier moraine dammed lake, Komori (2011) notes that the moraine is still stable and the lake is shallow near the moraine, suggesting it is not a threat for a glacier lake outburst flood. Mool et al, (2001) indicate the glacier was 3.4 km long and 0.3 km wide in the late 1990’s. Jain et al., (2015) noted that in the last decade the expansion rate of this lake has doubled. The glacier feeds the Chamkhar Chu basin which has a proposed 670 MW hydropower project under consideration. Here we examine changes in the Chubda Glacier from 1995 to 2015 with Landsat imagery.

In 1995 Chubda Glacier terminated at the red arrow and there was considerable ice cored moraine remaining in the southern portion of Chubda Tsho, green arrow.  The glacier is 700 m wide at Point E and has limited exposed bedrock areas just above the snowline above 2100 m, pink arrows.  A pair of secondary glacier have a joint terminus at the orange arrow In 2001 there are only minor changes from 1995.  In 2014 the snowline is at 2100 m, bedrock areas have expanded at pink arrows, and the amount of lake area at the southern end has expanded as ice cored moraine has melted out. In 2015 the glacier terminus has retreated 600 m since 1995, the lake area has expanded by ~2 square kilometers.  In 2015 the southern end of Chubda Tsho remains shallow and the wide moraine dam stable. The snowline is again at 2100 m and the glacier is only 500 m wide at Point E.  This indicates a continued decline in glacier flow into the terminus zone, which will lead to continued retreat. The secondary glaciers have now separated significantly, orange arrow.  The retreat of this glacier is similar to that of other glaciers such as Lugge and Thorthomia Glacier and just across the range in China, Zhizhai Glacier and Gelhaipuco Glacier.

chubde ge

Google Earth image of Chubda Glacier. Blue arrows indicate flow, brown arrow indicates wide moraine dam, green arrow indicates shallow moraine areas. 

chubde galcier 2001

Chubda Glacier 2001 Landsat image.  Red arrow indicates 1995 terminus location and yellow arrow is 2015 terminus location.  Pink arrows indicate areas upglacier of expanding bedrock. Green arrow indicates moraine areas amidst the lake.  

chubde glacier 2014

Chubda Glacier Landsat image in 2014.  Red arrow indicates 1995 terminus location and yellow arrow is 2015 terminus location.  Pink arrows indicate areas upglacier of expanding bedrock. Green arrow indicates moraine areas amidst the lake.