Roundup: AGU 100, The Third Pole, and Why Lake Superior is Rising

Latest Cryosphere Research Presented at AGU Centennial

GlacierHub’s senior editor attended the American Geophysical Union’s 100th meeting––combing the centennial gathering for groundbreaking cryosphere research. AGU 100 hosted more than 27,000 attendees––with an equal number of submitted abstracts. More than 1,000 oral sessions and 8,200 presentations were featured as well as more than 16,000 posters. Nearly two dozen scientific workshops were hosted, 101 town halls, ten tutorials, and five keynotes speeches. The Mountain Research Initiative hosted a synthesis workshop on future mountain climate change from elevation-dependent warming to elevation-dependent climate change, led by Nick Pepin from the University of Portsmouth, with experts from around the world. `

Notable glacier presentations over the course of the week included the possibility of a long subglacial river under the north Greenland ice sheet, a subglacial groundwater table beneath Greenland’s Hiawatha crater, measurements of tidewater glacier melt rates with underwater noise, the deglaciation of the Andes in central Chile, the role of ocean warming in the widespread retreat of Greenland’s marine-terminating glaciers, the geologic signatures of catastrophic glacier detachments, and significant surface melt detected across the Himalayas in synthetic aperture radar times series, among others. In case you missed it, AGU Cryosphere live-tweeted the research on display.

The 100th meeting of the American Geophysical Union was hosted in San Francisco, California December 9-13 (Source: Peter Deneen)

Is There Anything Natural About The Polar?

Is there a basis for calling the Himalayas––or all glaciers––a third pole? This article is one of the very few that explores both the social and scientific basis for answering this question positively. From the abstract: “Are similarities of temperature, snow and ice cover, and (certain) marine mammals sufficient to warrant both polar regions being considered a single object of study or governance? We argue that their treatment as a unit is an invitation to examine the motivations behind the choice to be polar rather than Arctic or Antarctic.”

Read the article here.

The Tibetan Plateau, often called the Third Pole (Source: NASA/WikiCommons).

Why Lake Superior Is Rising and What That Means for the City of Duluth

As a climate threat, sea level rise has been well-documented. However, it’s rising lake levels, linked to the warming climate, that may be threatening the shores of Duluth, Minnesota, a city recognized for its climate-safe attributes and that is being advertised as a safe haven for climate refugees.

Read the story by Audrey Ramming on GlacierHub here.

Time series plot of Lake Superior water levels: When working for NOAA, Gronewold helped develop the Great Lakes Water Level Dashboard as a tool to look at long term water level data in the Great Lakes. Notice the recent rising trend. The red line represents the average water level for the period of record while the blue dots represent the average water level in a given month. (Source: Andrew Gronewold/NOAA)

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Why Lake Superior Is Rising and What That Means for the City of Duluth

Duluth, Minnesota has been identified as a potential refuge for climate migrants who are fleeing from the damaging effects of climate change occurring in their respective hometowns. The city was selected based on qualitative, social criteria that makes it more appealing than other places, but was not deeply examined in terms of environmental impact or in terms of how climate change might be affecting the water level rise of Lake Superior. Ironically, long-term geological processes as well as recent heavy precipitation events linked to climate change, threaten even the most “climate-proof” city in the United States.

Duluth Skyline. (Credit: Evan Kane/Flickr)

The surface of the Great Lakes region is still in the process of bouncing back from the weight of massive glaciers that began retreating near the end of the last ice age 11,000 years ago. These glaciers and ice sheets, which were miles thick, literally pushed the Earth’s crust into its upper mantle. Now, with the glaciers gone, the earth’s surface is rising back upwards, a process known as isostatic rebound. The same way a yoga mat takes some time to return to its original shape after bearing weight––because of the thick consistency of the earth’s mantle––it will take many thousands of years for the land to return to its original equilibrium level.

However, the amount and rate of rise is not uniform across the Great Lakes region; it all depends on the amount of ice that was pushing the land down and how long ago it melted away. For instance, the Hudson Bay area was home to some of the most massive glacial ice sheets, and was the last to see its ice melt away. Thus, the land surface there is rising more than half an inch per year, which sums to over four feet per century.

Isostatic Rebound. (Credit: Brian McNamara/National Oceanic and Atmospheric Administration)

Moreover, rising land in some areas can cause the land to sink elsewhere, creating a sort-of seesaw effect. North America’s Great Lakes lie along the fulcrum of the seesaw: land north of the lakes is bouncing back up from the retreat of Canadian glaciers, causing the land south of the lakes to subside. As a result, residents on the southern shores are seeing water levels rise very slowly over time. 

Lake Superior itself is experiencing rising water levels on its southern shorelines while its northern shorelines are experiencing the opposite. In fact, a paper published by Lee and Southam in 1994, which examined water level limits for Lake Superior for the purposes of hydropower water diversion, stated: “Due to these natural changes, the upper regulation limit is now 0.21 m higher at Duluth, Minnesota, and 0.26 m lower at Michipicoten, Ontario, than in 1902. By 2050, these differences will be as much as 0.34 m higher and 0.43 m lower, respectively.” They concluded that the effects of crustal movement should be considered in long term planning, especially with regard to establishing flood levels along Lake Superior’s southwestern shore.

The contribution of isostatic rebound to water levels in the Great Lakes is just part of the lake level rise story. Andrew Gronewold, a professor in the school for environment and sustainability (SEAS) at the University of Michigan, explained to GlacierHub that while glacial isostatic rebound is indeed occurring over the Great Lakes region, it is not the reason why water levels are so high in Lake Superior right now. “Water levels are driven primarily by rainfall that enters the Lake Superior basin, and by the amount of water that leaves through evaporation,” Gronewold said, and “this increase in precipitation is largely the response to climate change across the region.”

Waves crashing in Lake Superior. (Credit: Tom Ruppe/Flickr)

Gronewold has been researching how changes in precipitation and evaporation lead to both short and long term changes in water levels in the Great Lakes. He mentioned that as recently as five or six years ago, water levels in the lakes were dangerously low. However, as a result of recent heavy precipitation events, Lake Erie and Lake Ontario just broke their all-time record for high water levels, and that goes back over 100 years. Lake Superior rose one meter in just five years. “It’s important to mention that the rate of change due to glacial isostatic rebound is not nearly as fast as the water level rise by precipitation,” said Gronewold. Researchers believe that rapid transitions between extremely high and low water levels could be the new normal as interactions between the global climate and regional hydrological cycles become more variable with climate change.

Not only has there been an increase in the number of precipitation events, but there has also been an increase in the number of heavy rainstorms. This trend is the result of a warming atmosphere, which can hold more moisture, Gronewold explained. Indeed, for every degree (Celsius) of temperature rise, the atmosphere can hold about seven percent more moisture. The Intergovernmental Panel on Climate Change (IPCC) pointed out that eastern North America is one region especially at risk of seeing the largest increases in heavy precipitation as the climate warms.

According to the IPCC, Earth’s surface warmed an average of approximately one degree C above pre-industrial levels by 2017. This rise might seem small, but the amount of energy that is required to heat the entire surface of the earth by one degree is extremely large. We are already seeing intense sea level rise along the Eastern Coast of the US, worsening wildfires in California, an immense decline in fishery productivity, and the exposure of hundreds of millions of people to climate related risk and poverty. This is forcing millions, especially those in coastal communities, to migrate places that are more climate safe.    

Time series plot of Lake Superior water levels: When working for NOAA, Gronewold helped develop the Great Lakes Water Level Dashboard as a tool to look at long term water level data in the Great Lakes. Notice the recent rising trend. The red line represents the average water level for the period of record while the blue dots represent the average water level in a given month. (Credit: Andrew Gronewold/NOAA).

Duluth, a major port city on Lake Superior, was identified among several other cities in the Upper Midwest as a potential climate refuge for those escaping the damaging effects of climate change in their own hometowns. Jesse M. Keenan, a lecturer in architecture at Harvard University, served as the principal investigator in the “Duluth Climigration” (climate migration) project. “We are seeing the northerly migration of flora and fauna, and the idea is that people will follow,” said Keenan.

“No city can be ‘climate proof,’ no one is immune from climate change,” Keenan explained in his lecture to Duluthians this past April, but there are places that are better insulated than others. Right next to Lake Superior, Duluth the “air-conditioned” city, makes a good case for being quite climate proof. Moreover, recent research out of the University of Maryland suggests Duluth may see a similar climate as Toledo, Ohio, a city 550 miles southeast of Duluth, by 2080.

The video above is a lecture given by Dr. Jesse M. Keenan in April of this year, and is geared towards informing Duluthians about why their city would make an outstanding “climigration” refuge.

“What do people look for when they move?,” Keenan proposed to GlacierHub. Duluth boasts urban affordability, a strong health care system, strong primary and higher education systems, and it also displays core infrastructure that would capture mid- and upper-income consumer preferences. Furthermore, the city has excess capacity for new housing and businesses because it is a residual of the rust belt which saw industrial decline and gradual depopulation starting around 1980. “It has been in a long, long population decline, so any measure of additional population resonates,” Keenan explained. Within the past decade, the entire town gained just 56 people. Though his team did not take into account the environmental impact component of migration in their decision, Keenan affirmed, “I do not discount the associated challenges of water management in terms of stormwater management and managed lake levels, but Duluth itself, has qualitative aspects that make it a good ‘refuge.’” 

Downtown Duluth on the shore of Lake Superior (Credit: Jacob Norlund/Flickr)

Keenan argued that if refugees were to move there, they should settle in high density housing downtown, rather than expand suburbanization, as it provides an opportunity to revive mass transit and build sustainably. “I think this is the most interesting part of the project, actually, because when people move, land becomes very inundated, and this is a chance to move away from the suburban high carbon footprint and build sustainable high-density housing,” Keenan remarked, “and it could easily be like the brownstones of Brooklyn – very nice and beautiful.” 

The important thing to figure out is who will be on the move, which market and demographics they will represent, and what this will mean for the housing lifecycle, tax base, and development. Many Floridians currently imperiled by intense storms and sea level rise may choose to relocate here because Lake Superior resembles the ocean. There have been people who have actually relocated to Duluth as a result of Keenan’s research – “They’ve read these papers and have said ‘That’s it, we’re moving to Duluth!’ Keenan said, and “I want to meet these people.”


The massive glacial ice sheets that carved the Great Lakes make Duluth a deepwater port. Ocean-going ships can reach it, even though it is situated far inland. (Credit: Sharon Mollerus/Flickr)

When asked whether Duluth might make a good climate refuge, Gronewold explained: “As a citizen of the region, I can say that Duluth is an amazing city and the Upper Midwest is a great place to live, but it’s really hard to untangle all the impacts that climate change might have, not only on water and temperature, but also on the economy.” Duluth’s location on Lake Superior provides a cool climate, fresh potable water, and a stable, deepwater shipping hub favorable for climate migration. But now the Great Lakes, to which Duluth owes so much, are changing as a result of slow geological processes as well as much more rapid climate change.

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Ice Cavers Travel Into the Heart of Glaciers

Ice cave at Lamplugh Glacier, Glacier Bay National Park, Alaska (Photo: Allyhook/Flickr)
Ice cave at Lamplugh Glacier, Glacier Bay National Park, Alaska (Photo: Allyhook/Flickr)

As their name suggests, ice caves are tunnel-like features that occur within ice bodies, usually glaciers. They have been known to science at least since 1900, when the American explorer and scientist Edwin Balch described them in his book Glacières or Freezing Caverns. In recent decades, some ice caves have become major tourist attractions.

Ice caves are formed by the horizontal movement of liquid water through glaciers. This movement causes some of the ice to melt. In some cases, the liquid water is produced by melting on the glacier surface; it then descends through a vertical tunnel or moulin to the glacier bed, where it flows out and emerges at the glacier snout. In other cases, geothermal activity provides the heat to melt the ice. Caves can also form on glaciers that terminate in lakes or the ocean; melting at the front of the glacier can proceed under the glacier, sometimes for considerable distances.

Ice caves attract tourists in a number of countries. Norway and Iceland are major destinations for people who wish the visit them, but they are found in other countries as well, including Switzerland, Austria, Russia, Canada, Argentina and New Zealand. The nature photographer Kamil Tamiola entered an ice cave on the north face of an Alpine summit in France at 3,800 meters above sea level. “You need to stay focused, pay attention to every single move and commit yourself entirely to this climb,” he said. He used mountaineering gear, including ice axes and crampons.

Less equipment is needed to enter the ice caves of Lake Superior, which form each winter from seeps in a limestone cave rather than from melting within a glacier. Tourists wear warm clothing and boots, and bring only trekking poles for balance. “It’s just fantastic, ” said Jim McLaughlin, who visited them in 2014. “It’s unique to see water in so many different forms and different colors and the way it’s sculpted.” McLaughlin and the others

Ice cave in  Belcher Glacier, Devon Island, Canada (Photo: Angus Duncan/NASA)
Ice cave in Belcher Glacier, Devon Island, Canada (Photo: Angus Duncan/NASA)

In all these countries, the best time to visit ice caves is during the winter. There is a greater risk of collapse from melting at other seasons. Tourists have to bring appropriate gear to enter an ice cave. Helmets, gloves, sturdy boots, and warm layered clothing are often required. Headlamps and kneepads are highly recommended.

There is a sense of urgency about glacier caving, since some of the caves are at risk of disappearing. Bob Krumenaker, the park superintendant at Apostle Islands National Lakeshore, where the Lake Superior ice caves are located, mentioned that people treat ice caving as “a truly endangered national park experience, because, like endangered animals, we can’t predict its future, and it may not be there,” The Sandy Glacier Cave System on Mount Hood in Oregon is also shrinking. In his website From a Glacier’s Perspective, Mauri Pelto writes of the complete disappearance of the caves on Paradise Glacier on Mount Rainier in Washington. For the meantime, though, a visit to an ice cave can provide a striking experience of the interior of a glacier.

Pond in ice cave under the Nigardsbreen, Jostedalsbreen, Norway (Photo: Guttorm Flatabø)
Pond in cave under the Nigardsbreen, Jostedalsbreen, Norway (Photo: Guttorm Flatabø)