The Wikipedia page for Taku Glacier needs updating.
Taku Glacier, the deepest and thickest alpine temperate glacier in the world, is no longer the only major glacier advancing in the Juneau Icefield––it is finally receding. Taku, which measures 4,845 feet (1,477 m) and 36 miles (58 km) long, was long heralded as a symbolic holdout to the melt that has most glaciers in retreat.
Mauri Pelto is a professor of environmental science at Nichols College and director of the North Cascades Glacier Climate Project. “This is a big deal for me because I had this one glacier I could hold on to,” Pelto told NASA. “But not anymore. This makes the score climate change: 250 and alpine glaciers: 0.”
The determination that Taku has succumbed to the warming climate was made after completing annual end-of-summer snowline measurements. Surface melt is responsible for the glacier’s turnaround, according to Pelto. The Juneau Icefield Research Program has been watching and reporting Taku’s yearly mass balance to the World Glacier Monitoring Service since 1946.
The glacier had been expected to continue advancing through the rest of the century. “To be able to have the transition take place so fast indicates that climate is overriding the natural cycle of advance and retreat that the glacier would normally be going through,” Pelto said.
The Taku Glacier is the largest outlet glacier of the Juneau Icefield in Alaska. Taku Glacier began to advance in the mid-19th century, and this continued throughout the 20th century. At first observation in the 19th century, the glacier was calving in deep water in a fjord. It advanced 5.3 kilometers between 1890 and 1948 moving out of the fjord into the Taku River Valley (See maps below (Pelto and Miller, 1990). At this time calving ceased resulting in positive mass balance without the calving losses. The glacier continued to advance 2.0 km from 1948-2013 (Pelto, 2017). The advance was paralleled by its distributary terminus, Hole in the Wall Glacier. This advance is part of the tidewater glacier cycle (Post and Motyka, 1995), updated model by Brinkerhoff et al (2017). At the minimum extent after a period of retreat the calving front typically ends at a point of constriction in fjord width or depth that limits calving. With time, sedimentation in front of the glacier reduces water depth and calving rate, allowing the glacier to begin to advance. In the case of the Taku Glacier, after a century of advance, the glacier had developed a substantial proglacial outwash and moraine complex that had filled in the fjord, and the glacier was no longer calving. Images below, from 1961 and 1981, illustrate this. This allowed the advance to continue through the rest of the 20th century and into the 21st century. The slowing of the advance in the latter half of the 20th century has been attributed to the impedance of the terminus outwash plain shoal (Post and Motyka, 1995; Pelto and Miller, 1990). There is a concave feature near the terminus with an increase in crevassing where the push impacts flow dynamics as seen at black arrow in 1975 and 1998 images below. In 1980’s the Taku Glacier’s accumulation area ratio was still strong enough for Pelto and Miller (1990) to conclude that the Taku Glacier would continue to advance for the remaining decade of the 20th century, which it did.
Beginning in 1946, the Juneau Icefield Research Program began annual mass balance measurements that is the longest in North America. In conjunction with JIRP and its first director Maynard Miller, we compiled and published an annual mass balance record in 1990. From 1990 to the present, in conjunction with JIRP and Chris McNeil, we have continued to compile and publish this annual mass balance record (Pelto et al 2013). Much of the remarkable data record of JIRP has this month been made accessible to the public, particularly through the efforts of Seth Campbell, JIRP director; Scott McGee, survey team director; and Chris McNeil, mass balance liaison with USGS.
Taku Glacier is one of the thickest known alpine temperate glaciers. It has a maximum measured depth of 1,480 meters, and its base is below sea level for 40-45 km above the terminus (Nolan et al 1995). Moytka et al (2006) found that the glacier base was more than 50 m below sea level within 1 km of the terminus and had deepened substantially since 1984. This suggests a very long calving retreat could occur. The glacier had a dominantly positive mass balance of +0.42 m/year from 1946-1988 and a dominantly negative balance since 1989 of -0.34 m/year (Pelto et al 2013). . This has resulted in the cessation of the long term thickening of the glacier. On Taku Glacier, the annual ELA (end of summer snowline altitude) has risen 85 m from the 1946-1988 period to the 1989-2019 period. During the 70+ year annual record the ELA had never exceeded 1,225 m until 2018, when it reached 1,425 m (Pelto, 2018). In 2019, the ELA again has reached a new maximum of 1,450 m (see above images). Contrast the amount of the glacier above the snowline in 2018 and 2019 to other recent years that had more ordinary negative balances (see Landsat images below).
In 2008 and 2012, JIRP was at the terminus, creating the map below. There was no change at the east and west side of the margin since 2008, with 55 to 115 m of advance closer to the center. The glacier did not advance significantly after 2013 and did not retreat appreciably until 2018. The Taku Glacier cannot escape the result of three decades of mass losses, with the two most negative years of the record being 2018 and 2019. The result of the run of negative mass balances is the end of a 150+ year advance and the beginning of retreat. Sentinel images from 2016 and 2019 of the two main termini Hole in the Wall Glacier (right) and Taku Glacier (left). The yellow arrows indicate thinning and the expansion of a bare rock trimline along the margin of the glacier. The Hole in the Wall terminus has retreated more significantly with an average retreat of about 100 m. The Taku main terminus has retreated more than 30 m along most of the front.
The retreat is driven by negative balances, mainly by increased surface melt. The equilibrium flow of the Taku Glacier near the long term ELA for the 1950-2005 period was noted by Pelto et al (2008). This occurred during a period of glacier thickening, average profile velocity was 0.5 md-1 (Pelto et al 2008). Since 1988 the glacier has not been thickening near the snowline as mass balance has declined slightly (Pelto et al 2013). The remarkable velocity consistency measured by JIRP surveyors led by Scott McGee each year at profile 4 has continued. It is below this profile that surface ablation has reduced the volume of ice headed to the terminus.
All other outlet glaciers of the Juneau Icefield have been retreating, and are thus consistent with the dominantly negative alpine glacier mass balance that has been observed globally (Pelto 2017). Now, Taku Glacier joins the group unable to withstand the continued warming temperatures. Of the 250 glaciers I have personally worked on, it is the last one to retreat. That makes the score: climate change 250, alpine glaciers 0.
To see more photos of Taku Glacier, check out the Mauri Pelto’s original post on From a Glacier’s Perspective, a blog published by the American Geophysical Union.
A new study published in the journal Isis details a decades-old conflict between early glacier researchers in Alaska, a conflict that remains relevant today. The controversy, known as the Miller–Beckey dispute, started at the Juneau Icefield in the late 1940s when a scientist-climber named MaynardMiller clashed with fellow mountaineer Friedrich Beckey. Beckey discounted Miller’s scientific research due to Miller’s secondary role as a mountaineer, suggesting that because Miller was a sportsman, he could not also be a serious scientist. The dispute took place at a time when North American glaciology was a nascent geophysical science.
The Background of the Conflict
The Juneau Icefield Research Project (JIRP), which brought both men to the ice, was one of the first programs of glaciology in North America, according to the article’s author, Danielle Inkpen. It was an on-site, long-term study of the Taku glacier, an outlet glacier of the Juneau Icefield. Intensive field observations like those made at JIRP required researchers to live on the ice for extended periods of time. Dangers such as hidden crevasses and snow blindness required the traditional skill set of a mountaineer. As a result, JIRP drew many fieldworkers from elite mountaineering circles.
Miller, founder and long-time director of JIRP, was one of these early adventurers. Inkpen writes that Miller was a skilled climber, having joined America’s first Mt. Everest expedition in 1963. But he was also an educated scientist who studied geology and glaciology, earning undergraduate and master’s degrees from Harvard and Columbia University, and a Ph.D. from Cambridge University. Miller’s dual roles as both an active mountaineer and scientific researcher prompted his rival Beckey to cast doubt on his scientific credibility. Nicknamed “lone wolf,” Beckey was a legendary American rock climber and an Alpine-style mountaineer. He is known to many from the documentary, “The Legend of Fred Beckey,” for having completed more first ascents than any other North American climber.
Miller was first introduced to the Alaskan glacier as a member of an expedition which first summited Mount Bertha, led by Bradford Washburn, his geography instructor at Harvard. Miller and Washburn built a sense of camaraderie when they were roped up together during a climb while both part of the Harvard Mountaineering Club (HMC). Later, Washburn recommended Miller as the field assistant for glacier research in Alaska in 1941 with William Field, one of the founders of the HMC and also a leading mountaineer, photographer and geologist in the 1920s with a number of first ascents to his credit. These men all came to glaciology through mountaineering. Miller’s passion for scientific fieldwork in Alaska originated in his desire to explore the climbing potential in southern Alaska.
The Conflict Develops
Miller returned to Alaska in 1947 for JIRP. The project’s primary funder was the Office of Scientific Research and Development of the American military. Inkpen explains that investment in glaciology was made possible by the United States military, which increased expenditures during the Cold War amidst national security concerns. The Polar region was a major geopolitical hotspot at the height of the conflict, and launching missiles from secret bases under ice caps was considered a possibility. Observations of Alaskan glacier fluctuations during this time triggered further investigations into the relationship between glaciers and climate. In order for JIRP to avoid a misunderstanding about their primary commitment to science, it had to keep its professional image as a glacial science organization, Inkpen notes. Other glaciological expeditions at the time, like Snow Cornice, were supported by private funders. As JIRP’s military sponsor said, ‘‘No funds could be provided for mountaineering.”
As a result of this policy, Miller did no climbing during the first summer of research at Juneau. However, he was reportedly located close to the attractive spire, Devil’s Paw. He also wrote an article about the mountaineering possibilities at Juneau Icefield for HMC’s Bulletin; according to Inkpen, Miller believed that this piece would go unnoticed by his funder. She quotes his article as stating that the 1949 season would bring “many interesting ascents of the magnificent granite and metamorphic rock peaks which protrude out of the ice and snow in this glacial-alpine paradise.”
Miller and Beckey had an unpleasant history before their confrontation in Juneau. Inkpen explains that as climbing partners, they failed to reach the summit of the Nooksack Tower in North Cascades National Park, in Washington State. However, Miller would later try a second time with another team, excluding Beckey. Then, in 1948, when Miller became field leader at the Juneau Icefield, he wrote a letter to Beckey telling him to stay away, Inkpen reports. She further notes that Miller claimed he was afraid that the press attention from Beckey’s first ascent would undermine JIRP’s reputation, especially at a time when the organization needed funding. However, the true purpose of the letter remains unknown. Inkpen indicates that it cannot be ruled out that Miller merged private affairs into public ones, wanting to save the first ascent for himself. Beckey followed Miller’s request for a time, but in 1949 he marched to Juneau unexpectedly and successfully conquered the Devil’s Paw.
The Consequences of the Conflict
Reverberations continued for Beckey and Miller after Beckey wrote to American Alpine Club (AAC) condemning Miller for practicing pseudoscience and using science as a cover for his mountaineering ambitions. Beckey further accused Miller of violating the codes of sharing information with fellow mountaineers. Certain gentlemanly rules inherited from the Victorian golden age of climbing governed first ascent. Using climbing information from other climbers to reach the summit was regarded as improper. Beckey even claimed that Miller had besmirched him and broke his climbing buddy’s arm during a visit.
Instead of declaring the scientific importance of his research to defend himself and the JIRP, Miller hit back as a mountaineer, reportedly stating, “That is the most unfortunate [and] uncalled for situation that has ever arisen to besmirch the name of the HMC and the AAC.” He asked the mountaineering community to ban Beckey’s actions and questioned Beckey’s integrity for deliberately concealing his climbing routes. As a result, the AAC convened a three-person committee to investigate this Miller-Beckey dispute. According to the article, the committee concluded the matter as an attack on Miller’s professional credibility in order to encourage the club members to work with scientific expeditions. Their judgment had a profound influence on interweaving scientific research with mountaineering, Inkpen reports.
As GlacierHub learned from ErinPettit, a glaciologist at the University of Alaska who conducts research and teaches at JIRP, the conflict between mountaineers and scientific research is still relevant today. “There certainly is a challenge when ego comes into play,” Pettit said. “If someone on a field team has more of a mountaineering ego, he/she wants to summit a mountain and put the science as a lower priority, that may be their choice. However, if it affects the goals of the entire field research team, then that is an issue. Similarly, a team of mountaineers might have the goal of achieving a new route on a mountain. If one of them is also a scientist and gets too distracted by science to support the goals of the mountaineering team, then the team will suffer.” Teamwork relies on having everyone on board with the goals of the team, she said. This involves each team member knowing what their role is on the team.
In the end, the Miller–Beckey dispute revealed a conflict between scientific and recreational values. It shows how pride and a competitive spirit can undermine the teamwork that is required for new accomplishments in the field, a topic of significance even today.
Anthropogenic environmental changes such as fossil fuel extraction and glacial retreat are two negative impacts affecting salmon species. But not all news is bad news. With retreating glaciers comes the possibility of producing new habitat for certain salmon populations, according to recent research published in BioScience.
Connecting Climate Change with Salmon Species
A total of five species of salmon swim within the rivers of the United States: chinook, coho, sockeye, pink and chum. Glacial retreat presents a variety of unknowns for these salmon species.
Among the climate change consequences, glacial melting upstream leads to changes in magnitude, timing, and frequency of flow downstream, which impacts nutrient levels as well as sediment levels. Warming of glacier-fed rivers due to warmer atmospheric temperatures could destabilize ecosystems and cause population die-offs. Significant warming of the oceans will also lead to damaging conditions for salmon species.
On a more positive note, glacial retreat could also drive the formation of new habitat for salmon species. Salmon use evolutionary adaptive strategies to colonize new streams and therefore are able to stray from their natal streams to find more productive waters. Evidence of this colonization has already been documented in Glacier Bay National Park with coho salmon.
How much new habitat will be created?
The Earth to Oceans aquatic ecology research team, led by associate professor Jonathan Moore, looked at the impacts of glacier retreat on salmon habitat, specifically which glaciers will establish new habitat. Kara Pitman, a researcher in the lab and a Ph.D. candidate at Simon Fraser University, told GlacierHub that approximately “thirty to fifty ocean-terminating glaciers in Alaska will produce new habitat.”
Areas in the Pacific Northwest and Alaska that have large, low-elevation glaciers will retreat back to expose this new habitat. The Bering Glacier in Alaska is one glacier that is likely to produce new habitat due to its low valleys, according to the researchers.
Pitman suggests that pink and chum species that spawn near the ocean in the river mouth may benefit due to new downstream habitats, and chinook, which spend more time in the freshwater rivers, may also benefit.
All species of salmon rely on both freshwater and saltwater throughout their lives to varying degrees. Adult salmon spend a few years in the ocean following primary development, but once adult salmon reach reproductive maturity, they undergo physical changes that prepare them to return to freshwater streams. When they reach appropriate stretches of freshwater, they release eggs and sperm into the water, allowing fertilization and the continuation of the cycle of life.
It’s also important to note that salmon are limited by stream gradient; as a result, they will not be able to swim up into many of the new habitats.
Pitman says that there are no salmon present in these newly formed waters at the moment, so there are currently no negative consequences of glacial retreat on these salmon populations.
“There may be no salmon now, but there might be in several years, so there will be impacts,” shesaid.
Mining’s Impact on Salmon Populations
At the same time, human interference such as negligence and reliance on fossil fuels negatively impacts salmon ecosystems across the world, including in Alaska and the Pacific Northwest. Industrial runoff from mines leaches into nearby streams, pollutes the water and poisons the fish. Preventative measures to manage waste and clean up efforts are not yet developed and little effort seems to focus on advancing protective policies.
For example, mining in Northwest British Columbia and Southeast Alaska is a serious issue that affects Taku, Stikine, and Unuk watersheds. The Taku River contains all five species of salmon and is glacial-fed from Taku Glacier. It is likely that in the near future acid mine drainage will harm fishing and tourism industries, indigenous cultural activities, and local peoples.
Similarly, near Bristol Bay in southwestern Alaska, a new mega mine is undergoing proposal and review. The Pebble Mine would be the largest mine in North America and could wreak havoc on one of the most productive salmon ecosystems.
Immediate action is required to halt future fossil fuel excavation projects and protect wild salmon populations in Northern Pacific and Alaska.