This week’s Photo Friday features the Tasman Glacier in the Southern Alps of New Zealand’s South Island. At over 23 kilometers, the glacier is the longest of New Zealand’s more than 3,000 glaciers.
The photographer, Ryan Force, took the image from the Tasman Glacier viewpoint. Force and his wife, Marissa, honeymooned on the island by campervan. They intended to park near Mount Cook, the country’s highest peak, and hike to a promontory to view the glacier. But heavy rains in the region days earlier washed out a bridge on the road to the access point. The photo below was as close to the Tasman Glacier as the newlyweds were able to get.
The Tasman Glacier is in rapid retreat. The body of milky grey water in the foreground of Force’s photo is Tasman Lake, which formed as the glacier’s ice melted and continues to grow as the glacier recedes.
In 1973 there was no lake in front of the Tasman Glacier, according to Martin Brook, a lecturer in physical geography at New Zealand’s Massey University. The lake is now 7 kilometers long, 2 kilometers wide, and 245 meters deep.
A significant ice calving event in February of this year created a two-meter surge that damaged a jetty and several boat trailers on Tasman Lake, the BBC reported.
A sign at the Tasman Glacier lookout informs tourists of the glacier’s decline. New Zealand’s Department of Conservation uses the visual display of their rapidly retreating glaciers as an opportunity to raise awareness about climate change.
“We felt a bit defeated,” Force told GlacierHub of the experience. “I felt a little frustration that in the next 50 years, this beautiful landscape might be gone entirely because we as a species put our heads in the sand and refused to take action.”
A 2015 study on the implications of climate change for glacier tourism in New Zealand found glaciers to be a fundamental motivation for visitors, finding a “last chance dimension” luring visitors to the glaciers.
New Zealand’s Department of Conservation estimated that 945,000 people visited Aoraki/Mount Cook National Park in 2018. The surge in visitors to the park, which contains the Tasman Glacier, is a 17.5 percent increase from the previous year.
Although travelers produce a substantial carbon footprint through last-chance tourism, it may help bolster the sense of place attachment and identity that encourages tourists to engage in carbon offsetting, GlacierHub reported last month. People sometimes build personal connections to places they visit, and this value they put on locations may lead them to take meaningful action to preserve them.
“It was so valuable to actually see it firsthand,” said Force. “This was the first time I saw with my own eyes what the results looked like, instead of reading about them in an article or seeing it in a documentary. I walked away wanting to do more.”
Resulting from an unprecedented marine heatwave, the nationwide average temperature in New Zealand for the record-breaking summer of 2017-2018 was 18.1oC, over 2oC above average. Sea surface temperatures varied from 2-4oC above average and even reached 6-7oC above in some areas, the highest temperature anomalies in the world at the time. More, small and medium-sized glaciers in New Zealand’s Southern Alps lost over 13 percent of their total ice volume.
The Southern Alps mountain range, which cuts diagonally across New Zealand’s South Island, is home to over 3,000 small and medium-sized glaciers, which respond to climatic changes––both anthropogenic and natural––much faster than large glaciers. Since the last Little Ice Age ended in 1860, these glaciers in the Southern Alps have notably receded, save for four periods of advancement: around 1950, 1980-1987, 1991-1997, and 2004-2008.
In a new study, published in the International Journal of Climatology, lead researcher Michael J. Salinger of Pennsylvania State University and his co-researchers provide new estimates of glacier ice volume changes and the impact of climate variability on New Zealand’s small and medium-sized glaciers. From 1977 to 2018, the total ice volume of small and medium glaciers went from 26.6 to 17.9 cubic kilometers, a 33 percent decrease.
The researchers utilized a 42-year set of measurements––an annual measurement of the altitude of the end-of-summer-snowline (EOSS)––from 1977 to 2018 to calculate the ice volume changes for a sample of 50 glaciers in the Southern Alps. The EOSS is the boundary between the current year’s new, clean snow and older, dirty snow and is measured in mid to late March, which is the end of New Zealand’s snowy season.
If a particular year experiences lots of melting, the snow line rises in elevation, whereas if snow accumulation exceeds ablation, the snow line will move down. “It’s like doing your annual budget reconciliation,” said Salinger. “So on the 31st of March, [you are] working out whether you’ve received more or less income.”
When researcher and co-author Trevor Chinn started the EOSS monitoring program in 1977, Chinn calculated the volume for all of the over 3,000 glaciers he had mapped. Salinger explained that for this study, the researchers looked at current EOSS elevation compared to years past, using that information to work out the area lost or gained, then convert that to volume of water. “I can work out the glacier contribution from sea level rise, and what I’ve found is that it has been much higher than expected,” he noted.
Natural climate variability was a primary contributor to interannual fluctuations in glacier ice volume during this time period, even though anthropogenic warming is ultimately responsible for the accelerating downward trend. Volume gains in the 1980s and 1990s were offset and quickly surpassed by rapidly accelerating ice loss from 1998-2018.
The primarily land-covered mid-latitudes of the Northern Hemisphere are much different compared to the mostly ocean-covered midlatitudes of the Southern Hemisphere, which results in strong westerly winds. Salinger cited the Southern Annular Mode (SAM) as the most important source of variability in the Southern Hemisphere. “You can think of the [SAM] as squeezing and relaxing of the westerlies, or the Roaring Forties and Furious Fifties as we call them, over the Southern Ocean,” said Salinger.
In its negative phase, the SAM produces enhanced westerlies, cooler weather, and storm activity. In the positive phase, the strong westerlies move south while westerlies in the mid-latitudes weaken, and the weather gets warmer.
“Temperatures go up and you get less precipitation producing weather and more rain than snow precipitation,” said Salinger. The SAM usually fluctuates between positive and negative phases over weeks to months, but in response to anthropogenic warming, it is becoming increasingly positive.
Salinger noted that to a lesser extent, the El Niño Southern Oscillation also causes interannual climate variability in New Zealand. During an El Niño event, the equatorial easterly trade winds are subject to westerly wind anomalies, which would enhance the negative phase of SAM, leading to even cooler temperatures. La Niña pulls the trade winds in the opposite direction, further weakening westerlies over New Zealand and contributing to more warming.
As anthropogenic warming intensified over the last century, glaciers all around the world retreated, losing ice volume, and contributing to sea level rise. At the same time, natural climate variations happening on interannual and decadal timescales also worked to temporarily offset this massive retreat, even contributing to periodic glacier advances for small and medium-sized glaciers in New Zealand. Ultimately though, glaciers are driven primarily by temperature, and so the impacts of the global warming trend will prevail.
Changing glacier ice volumes throughout New Zealand pose great risks to the country, which relies heavily on hydropower for energy production and on tourism and agriculture for economic output. Salinger cited recent agricultural droughts on the South Island, and the mounting problems faced by farmers without access to irrigation on tap.
Interestingly, New Zealand uses the visual of their rapidly retreating glaciers as an opportunity to raise awareness about climate change. “Our glaciers are iconic, and people are not too far from them, so they are very familiar with them. They’ve seen the huge retreat of some of the glaciers up valleys with melting, because of global warming. It’s something tangible and people can see the long-term change,” said Salinger. “So that’s why we find our glaciers as sort of the canary in the coal mine.”
The remains of an outdoor ice rink near Mount Harper/Mahaanui in New Zealand offer insight into the establishment, use and decline of what may have been the largest outdoor ice rink in the Southern hemisphere. The privately built rink on South Island was a popular social amenity from the 1930s to the 1950s, playing an important role in the development of ice hockey and skating in the country, as detailed in a heritage assessment carried out by Katharine Watson for New Zealand’s Department of Conservation (DOC). A combination of interviews, secondary sources and an archaeological survey were used to inform the history of the rink present in the assessment.
Mt. Harper ice rink lies in the lee of the mountain (the side that is sheltered from the prevailing wind) that gives it its name, at the foot of the glacier-clad Southern Alps of New Zealand. It was built in the early 1930s by Wyndham Barker, the son of a minor member of the English gentry who lived in Canterbury and learned to ice skate while studying in Europe, as explained in the assessment.
The rinks no longer contain any ice and some now contain vegetation, but the bunds (earth mounds) surrounding the ice rinks can still be seen. Many of the original buildings, such as the ticket office, toilet block, skate shed, a hut built to house the Barker’s cow, Sissy, and the Barker’s house are still standing.
The rink was first built in the summer of 1931-1932 and was fed by water from a nearby stream. However, its original location was too exposed to the nor’westers (strong north-westerly winds that are characteristic of Canterbury in New Zealand), which rippled the ice. Barker subsequently moved the rink closer to Mt. Harper, building the rink by allowing controlled layers of ice to build up over many nights. The rink’s first major public season took place in the winter of 1934.
A hydropower scheme was also installed in 1938 to power lights for skating at night, while allowing water to be sluiced onto the ice if necessary. “The whole landscape is really legible today, which is one of the things that makes it such a great place,” Watson explained to GlacierHub.
“These kinds of sites are very important records of the myriad ways in which human societies have used, interacted with, and taken advantage of seasonal ice over time,” added Rebecca Woods, a professor of the history of technology at the University of Toronto. “An archeological site like Barker’s rink would be a candidate for a cool virtual reality tour along the lines of a New York Times 360° video.”
The potential of the site to tell the story of outdoor ice skating and ice hockey in New Zealand has been identified by the DOC. “The designation of the site as an Actively Conserved Historic Place recognizes this and entails a commitment to maintain the key buildings and structures in the expectation that despite being fairly isolated, the difficulty of access may change some time in the future,” shared Lizzy Sutcliffe, a representative from the DOC.
The rink was subdivided over its first few years of use, with up to seven rinks existing in the 1940s. One reason for doing this was that the ice was not freezing well. It also allowed one of the rinks to be dedicated to ice hockey, which Barker was passionate about. In fact, he was an important figure in the history of ice hockey in New Zealand, establishing the Erewhorn Cup, an ice hockey tournament that persists to this day.
“The main focus of the rink was definitely ice hockey, along with recreational skating,” Watson explained to GlacierHub. “Competitive ice hockey matches were held at the rink.” The remote location of the rink also meant that it had to be accessed using a punt until a swing bridge was built in later years.
At the time, ice rinks in South Canterbury were all located in the high country, close to the Southern Alps, which meant that most of them were associated with high country pastoral stations farmed by people perceived of as the elite. This rink was probably important in introducing people outside the pastoral stations to ice skating, as it was more accessible to the people of Geraldine, the nearest town. The rink’s development and success were part of a larger movement in New Zealand at the time, where there was increasing leisure time and people were more frequently exploring the outdoors and taking up winter sports, according to Watson.
Gender could also have had an effect on the use of the rink, according to Woods. She explained to GlacierHub that gender has influenced many realms of human interaction with ice, likely extending to the use of ice rinks. “The competitive [ice hockey] matches were all played by men,” added Watson.
Public use of the rink ceased in the mid-1950s for a few reasons, one of which could have been climate change. “Anecdotal evidence suggests that warmer winters were one of the reasons the rink was abandoned,” Watson said. “The later owners of the rink did purchase a refrigeration unit at one point. This seems to suggest that things were getting warmer.” Another reason for the closing of the rink might have been World War II and the changes it brought about including the increased cost of fuel, which made it harder to get to the rink.
The remains of the rink offer some insight into one aspect of past human interactions with ice in New Zealand. Its completeness also makes it an interesting place to visit, if one is willing to make the journey to this remote region. Amidst the remains, it would be easy to imagine the laughter and enjoyment of people skating there, just as they would have done this winter if the rink was still operational.
“Given how dramatically the planet’s temperature is rising, it’s more critical than ever to document these instances [in human history] and demonstrate them to the public,” concluded Woods.
Read more about the rink and view additional photos here.