Climate change has long been known to be a stressor on glaciers the world over, but a recent study published in Nature Geoscience, reveals just how bad it’s been for those in the Andes: Glaciers in this South American mountain range have the unfortunate distinction of being both the fastest melting and the largest contributors to sea level rise in the world.
Glacial melt has been watched carefully for decades, but because of limitations in technology and methodologies, scientists haven’t gotten the most precise picture of how much melting is occurring, or how fast.
Previous techniques looked at regional locations scattered throughout the Andes like the Northern Patagonian Icefield and then extrapolated those findings. Others gave hazy estimates from low-resolution, remote-sensing images. But these methods can miss individual glaciers and clusters of just a few or more.
In an attempt to refine understanding of Andes-wide glacial melt, the researchers harnessed the image-collecting power of a satellite with the Asimovian name of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). ASTER has been taking high-resolution, stereoscopic images of the Andes since 2000. By compiling these images and integrating them into digital models, the study’s scientists were not only able to get a new ice loss estimate for the entire Andes, but also for individual regions and individual glaciers over the past two decades.
With this high resolution dataset, the researchers determined that the entire glacial range in the Andes shrunk about 23 gigatons (1 gigaton=1 billion tons) since 2000—more than previous studies have found—and account for 10 percent of global sea level rise. At this rate, some of these ancient glaciers will be gone in just over two centuries—but the rate is accelerating.
Digging through the data, the researchers also parsed out an array of differing melt rates between glaciers that revealed the areas of the heaviest melting: Patagonia (Chile, Argentina) and the tropical Andes (Colombia, Ecuador, Peru, and Bolivia). Previous research has shown that low altitude glaciers in some of these areas like Peru have lost as much as 50 percent of their mass since 1970.
“[Patagonia] is the region that contains the largest surface of ice, and [so] it’s normal to expect that the highest loss is going to be there,” lead author and glaciologist Inés Dussaillant told GlacierHub over the phone, adding that glaciers terminating in oceans and large lakes like those in Patagonia also experience heavy amounts of calving—which accounts for more than half of all the ice mass loss observed in the Andes. The glaciers in the tropics—mostly in Ecuador and Colombia—Dussaillant explained, are relatively small and highly sensitive to changes in climate. “A small change in temperature can make tropical glaciers lose a lot of mass,” she said.
Perhaps the most troubling of the team’s findings, however, dealt with glaciers’ contribution of freshwater to rivers through snow and ice melt. During the summer months, snow and ice melt from glaciers flows into streams and rivers, adding to the overall water availability of a particular region. This is particularly important in the Dry Andes of the northern and central regions of Chile and Argentina. Since 2010, these heavily populated semi-arid regions have been strapped in what climatologists have called a megadrought. The team found that increased glacial melting in these areas since 2009 actually helped to mitigate some of the most severe impacts of the drought. But as glaciers continue to shrink because of anthropogenic climate change, their ability to act as this natural salve is going to diminish or disappear.
“They are not going to be able to contribute to rivers eternally,” remarked Dussaillant. “There will be a moment where they’ll no longer be able to contribute during these periods of drought.”
This point highlights the larger implications of the study, which is that millions of people live near, and depend upon, these glaciers in the Andes, and the drastic reduction or total disappearance of them is going to have potentially severe consequences. Dussaillant, who is Chilean, pointed out that more than half of the population of Chile lives in or near the capital city Santiago, which lies in this region.
Eyal Levy, an industrial engineer and Andean climber who is also from Chile, told GlacierHub that Chileans are “starting to become very worried about the water stress. He added that rural areas and poorer communes around Santiago have been “seriously impacted.”
Glaciers are a conspicuous part of the everyday scenery, Levy said, and their shrinking takes a toll on people’s emotions. “People talk about melting glaciers with sadness, worry, and without knowing what to do,” he said.
Dussaillant hopes that the high resolution dataset gathered from this study will be used by other glaciologists for local or regional studies. “I study glaciers because they tell us what is happening,” she said. “It’s showing us that climate is changing, and the climate is a global thing. So what’s happening in the Andes … it concerns us all.”
A multinational team of scientists taking ice cores from glaciers on Peru’s tallest peak, Huascaran, withdrew from their research site on August 5 due to opposition from residents of the nearby Musho village, who suspected the scientists of causing environmental damage to the mountain and of illegal mining.
When they were asked to leave, the scientists had been on Mount Huascaran for about four weeks and had already completed the extraction of the two pairs of ice cores that they needed for their project. The team was evacuated soon after by a helicopter provided by the national police force. However, they left the samples they had collected on the mountain. Soon after, they entered talks with locals and government officials to find a solution that would enable them to retrieve the ice cores. After a few tense days, the government provided a helicopter to transport the ice cores and drilling equipment. Peruvian members of the expedition were allowed to bring the ice cores and drilling equipment down the mountain, and the expedition came to a successful close.
Where the dispute took place
Huascaran National Park covers 1,375 square kilometers in the Cordillera Blanca in the Ancash region of north-central Peru. It is home to 660 glaciers, 300 glacial lakes, and 27 snowy mountains, Huascaran being just one. The park was created in 1975, declared a UNESCO Biosphere Reserve in 1977, and a UNESCO World Heritage Site in 1985.
Some of the tension that led to the conflict can be traced back to historical influences from the founding of the park and the governance of land areas within it. The park is managed by the National Service of Protected Areas (SERNANP), under Peru’s Ministry of the Environment. There are a number of communities, Musho village included, located close to its boundaries. The roads into the park pass through community lands and the peasant communities often exercise rights over those roads. They sometimes regulate, limit, or close traffic to the park. In theory, the government could set rules for travel on the roads, but local communities exercise control over them. Additionally, local communities hold customary rights over pastures and woodlands within the park. Those rights existed prior to the establishment of the park. However, now the communities’ access to these areas is more limited.
Peru passed legislation that bans resource extraction within protected areas without explicit government approval. For those projects that do receive approval, concessions are granted within park land, usually to private firms. In spite of this legislation, the area has a long history of illegal mining operations which take place without formal approval. Over time, they have generated suspicion in local communities of the intentions of outsiders visiting Huascaran.
Luis Vicuña, a sociologist at the University of Zurich, explained that the Ancash region is the site of many environmental problems related to mining. He told GlacierHub that “in recent years, illegal mining has increased in this region,” referring to small scale operations by individuals and groups.
Legal mining operations conducted by large, international firms have also raised suspicions. Some of these operations have caused soil and water contamination. People in affected communities have suffered a variety of health problems, from nosebleeds and headaches to cancer and neurological disorders, and their water supplies have become too polluted to serve for irrigation or domestic use.
The parties involved
The three main parties to the dispute were the team of scientists, the government agencies which issued the permits, and the local communities who objected to the expedition.
The expedition was led by the renowned American paleoclimatologist Lonnie Thompson. It was composed of about a dozen scientists hailing from around the world. Team members were French, Russian, Italian, American, Mexican, and Peruvian, and included scientists from the National Research Institute for Glaciers and Mountain Ecosystems (Instituto Nacional de Investigación en Glaciares y Ecosistemas de Montaña or INAIGEM). Over the course of his career, Thompson has published 245 peer-reviewed publications, acquired 76 research grants, and gained world-wide recognition for being one of the first scientists to collect and analyze ice cores from mountain glaciers in tropical and subtropical regions. His expedition was funded with $1.5 million provided by the National Science Foundation. Analysis of the samples was planned to be conducted at Ohio State University, where Thompson has been a professor since 1991.
Gustavo Valdivia, who assisted Thompson with logistics for his expeditions, described it as a joint project between Ohio State University and INAIGEM. “INAIGEM has been doing field research in the Huascaran Glacier since 2014, so this expedition was supposed to build on INAIGEM knowledge, research experience, and relations in the area,” he told GlacierHub.
Paolo Gabrielli, an Ohio State University researcher and one of the scientists on the expedition, told GlacierHub that “the major goal of the expedition was to collect a tropical ice core that was cold enough to extract a pristine record of methane.”
Methane is an important greenhouse gas that is more powerful in retaining heat than carbon dioxide, despite being less common. It is also less well understood than carbon dioxide.
“Another important objective,” added Gabrielli, “is to infer information about the development and evolution of this large forested area [in South America] since the last glacial age (25,000 years ago).” The National Science Foundation website has an online summary of the award Thompson received to fund the expedition. It lists six main objectives for the research, including establishing timescales for the ice cores and studying climate and environmental effects variations in the mid-Holocene period.
Peruvian government agencies granted permits to the research team. The Ministry of the Environment and INAIGEM, a specialized technical body attached to the Ministry of Environment, oversaw the granting of the permits. According to its website, INAIGEM was founded to promote scientific and technical research on glaciers and mountain ecosystems for the benefit of citizens and to adopt adaptation and mitigation measures in the face of climate change.
The locals came from the village of Musho, a small village near the national park. It is the main entry point to the park for climbers who wish to summit Huscaran. The researchers went through Musho on their route to ascend to the glacier. The research team chose mountain guides and porters in the best interest of safety and the training and experience of the guides, Thompson told GlacierHub. “Most of the high elevation porters came from Huaraz and Cusco while porters, arrieros and burros/horses were hired from Musho. Local Musho residents transported expedition equipment, core boxes etc. from Musho up to the Alpine Hut,” he said.
Timeline of Events
“Press conferences were held in Lima on June 27, Mancos on July 4, at the base of Huascaran and on July 5 at the headquarters of the Huascaran National Park,” Thompson told GlacierHub. He continued, stating that they were held “to explain the scientific objectives and to answer questions and concerns of local people and the press concerning the Huascaran Expedition before starting the project. These press conferences were widely aired on TV and local papers.”
An article announcing the upcoming expedition was published on June 26 in Agencia Peruana de Noticias, a news outlet run by the Peruvian government. Prior to the 26th, foreign scientists and Peruvian agencies coordinated with each other about the expedition. On June 27, the Ministry of the Environment tweeted about the goals of the group’s work and included photos of Thompson meeting with Minister of the Environment Lucia Ruiz Ostoic and the executive president of INAIGEM Gisella Orjeda Fernández at the Lima press conference.
Gabrielli maintained a log of the expedition’s progress on his Twitter account. It tells how the team began ascending the mountain with an acclimatization hike to Laguna Shallap (elevation 4,250 meters), before reaching the Refugio Huascaran, a rustic mountain lodge (elevation 4,675m).
On July 9, the president of Peru, Martín Vizcarra, flew in a helicopter to visit the research team at the climbing hut above the village.The trip was reported on by several Peruvian news outlets, both on their own websites and on their social media feeds. Stanislav Kutuzov, another member of the research team, told GlacierHub that during his visit the president “offered all support including providing a helicopter for the transport of the equipment and ice cores from the basecamp to the heliport at the valley.”
After President Vizcarra’s visit, the researchers continued up the mountain, making camp at various elevations. On July 20, the 24th day of the expedition, the first ice core was extracted and on day 27 the drill reached bedrock at 167 m. On day 28, the team started to drill a second core at the same altitude, which they completed two days later, on July 26. Drilling began at the south summit to collect the second pair of ice cores on July 31 and both were completed by August 3.
The villagers from Musho first expressed their discontent with the expedition around July 31 or August 1. Kutuzov was a member of the team that had gone up to the summit to check progress on the drilling. “The drilling team was still at the summit of Huascaran when we received the text message that the local villagers are not happy about this project and suspect a mining operation at Huascaran mountain,” he told GlacierHub. “The next day (1 or 2 August) about 50 agitated local people went up to the basecamp and demanded an immediate termination of all works, and that all foreigners should leave the mountain, ” Kutuzov said.
Thompson and two other members of the expedition met with the group of protestors at the basecamp and listened to the complaints. “The complaints ranged from our team polluting the local drinking water to the President’s helicopter killing a cow,” Thompson said.
On August 5, a Peruvian police helicopter evacuated all foreign members of the scientific team to the city of Huaraz to wait until a solution could be found. This was done to meet the local community’s demands. All the materials, equipment, and ice cores were left on Huascaran.
The porters and mountain guides were asked to descend from the mountain on August 7. On their way down, they and their police escorts were detained by local people in a field outside of Musho. The group remained in the field until 6am when 30 police cars and armed officers arrived to escort them out of Musho.
A Facebook page was launched in the immediate aftermath of the evacuation called La Frente de Defensa por los Intereses del Nevado Huascarán (The Defense Front for the Interests of Mount Huascaran). It posted statuses explaining why locals interrupted the research and stating concerns of illegal mining and a lack of information coming from the Peruvian government regarding the expedition.
On August 10, Gabrielli tweeted that the scientists, villagers, and local institutions were working to resolve the situation. On August 11, the researchers were invited to Musho village to explain the goals of the project to the local communities, Kutuzov told GlacierHub. The video below shows Thompson speaking at the meeting in Musho village. It was taken by a local resident who posted it to Facebook.
After several days of negotiations, it was agreed that the ice cores and drilling equipment could be retrieved from the mountain, a point which had been a matter of deep concern for the scientists. However, Wilmer Sanchez Rodriguez, an environmental engineer and a member of the expedition, told GlacierHub that only the Peruvian porters, mountain guides, and scientists from the expedition were allowed back on Huascaran. The foreigners did not return.
The team was given three days from the first helicopter flight to retrieve the ice cores and remove all the materials left on the mountain. The time was set from the first flight because the team needed time to get people back on the mountain after everyone had been evacuated. The three day period lasted from August 16 to 18.
The expedition came to an end on August 18 when the last of the materials was removed. Orjeda, the president of INAIGEM, and the Ministry of the Environment tweeted that the expedition achieved its goals that day. Various news sources posted articles stating that the expedition successfully concluded on August 19 and 20. However, the Frente de Defensa por los Intereses del Nevado Huascaran posted on August 21 and called the incident an attack on the country’s heritage and ecosystems.
Different Points of View
Vicuña said that the “two perspectives are lacking a kind of dialogue,” characterizing the breakdown in communication between the scientists (and the national agencies which supported them) and the local communities which led to the growth of rumors and divisions.
From the point of view of those who supported the expedition, the scientific research could advance both basic and applied science. The expedition’s underlying scientific mission centered on studying changes in temperature, precipitation, atmospheric chemistry, temperature, and biodiversity in the region over the last 20,000 years. Huascaran is influenced by both the Pacific Ocean to the west and the Amazon to east—both areas of great interest in research. The research could also contribute to a better understanding of climate change and the challenges the region may face in the future as the glaciers melt and water supply from meltwater changes. The results could inform public policy going forward. Moreover, from the perspective of the scientists and the agencies, the expedition was fully legitimate. According to INAIGEM, the expedition was authorized by the Ministry of the Environment, through INAIGEM, and was authorized by the national park authority, SERNANP, to enter the park. In other words, they had obtained the necessary approvals to legally conduct their work.
Additionally, Thompson told GlacierHub: “For the Huascaran project (and indeed all of our projects) local people are informed through local lectures, press conferences and a project brochure that are widely distributed before an expedition, written in both English and the local language (in this case Spanish).” Due to these actions, the research team believed they had taken the necessary steps to make residents aware of their work.
Liam Colgan, scientific editor for the International Glaciology Society’s Journal of Glaciology, told GlacierHub about why the taking of ice cores in the Southern Hemisphere is considered particularly important research. “Since these records are often regional, Southern Hemisphere records are very valuable for complementing Northern Hemisphere records,” he said.
Colgan added, “Mid-latitude Southern Hemisphere glaciers currently have some of the highest ice loss rates in the world, which makes them some of the most endangered ice masses on Earth.”
From the point of view of the locals, however, there was great dissatisfaction with poor communication and concerns that nefarious activities were taking place. Some of their suspicions came from preexisting distrust created by illegal mining operations and from the long history of tensions between the park and the communities. Expeditions have sometimes been connected to mining that harmed the region and the local people were suspicious of outsiders who brought drilling equipment to the peak. Locals stated that they had not been involved in or notified of the permitting process carried out by INAIGEM and were unsure of the intentions of the scientists.
A resident of a local village, Elmer Aguilar, told the Associated Press that villagers were angry that they had not been informed of the expedition and that many farmers were under the impression that the scientists were scouting for a mining company. An article in Prensa Huaraz also blames INAIGEM for a lack of communication. In addition to the rural residents who expressed concern, a more senior official, the mayor of the province of Yungay, Fernando Casio Consolación, told ABC Noticias Peru that he was never informed by INAIGEM that the research would take place.
There was a large online response to the events by local community members, with discussion on certain groups, pages, and an individual’s status being shared hundreds of times. The Facebook page of Frente de Defensa por los Intereses del Nevado Huascarán posted on August 7 that 50 people were on the mountain illegally trying to extract minerals. The post was shared 617 times as of September 2.
Similar Situations in Peru and Elsewhere
“As far as we know there are no official studies or statistics that refer to whether [such conflicts] are recurring,” Vicuna told GlacierHub.
He gave an example of a project, financed by Swiss development assistance funds, which installed a high-tech early warning system for glacier lake outburst floods high in the Cordillera Blanca near Huascaran, at Laguna 513. A number of locals opposed it. The Laguna 513 case escalated. After rumors spread that the equipment was preventing the formation of clouds and causing a drought, a number of locals dismantled the station.
Data on the frequency of such conflicts taking place in Peru does not exist.
Valdivia mentioned other occasions where agencies met opposition from locals. He cited problems with the National Meteorological Service installing a weather station and the Ministry of Culture operating archaeological excavation sites.
Potentially adding to or fueling the locals’ suspicions are the high rates of corruption in the Ancash region. According to a recent document produced by La Defensoría del Pueblo, a constitutional body meant to investigate claims against public authorities, the Ancash region experienced a 67 percent increase in cases of crimes against the state between 2016 and 2018, the highest increase in Peru. In 2018, there were 661 complaints of illegal agreements between public officials and entrepreneurs or large businesses.
Outside of Peru, issues of land rights and sovereignty have led to similar conflicts and debate between scientists and local communities. For instance, the construction of the Thirty Meter Telescope in Hawaii was temporarily blocked by protestors to whom Mauna Kea, where the telescope is being built, is sacred. The protests have brought up issues of land rights and self-determination of local communities.
However, there have also been projects that have successfully been completed by building trust and relationships with local communities. One such case is that of construction of the Kitt Peak National Observatory, where relations between scientists and native peoples developed slowly over decades, allowing trust to be established. Scientists explained their purpose and goals to the tribal council elders who governed the Native American Tohono O’odham Nation and the elders willingly leased 200 acres of land for the construction of an observatory for educational and research purposes. The conflict in Peru played out more along the lines of the Kitt Peak case than the Mauna Kea dispute.
What caused the opposition?
The strength of the opposition in Peru stands in stark contrast to the large amounts of publicity which the expedition received in Peruvian media before it began. It is unclear why it took locals almost a month to respond to the researchers’ presence and how misinformation spread despite public endorsements of the expedition from the Ministry of the Environment, INAIGEM, and even a visit from Peru’s president. Valdivia pointed out how both INAIGEM and Thompson have a history of doing research in this area of Peru and emphasized the need to determine what was different about this expedition from past trips that took place more smoothly.
“The project suffered greatly from inaccurate and deliberately false statements made on social media during the course of this project even by some of our own team members which actually put team members and the success of the project at risk,” Thompson told GlacierHub.
Some elements can be traced to explain this conflict, including the long history of tension between the park and the communities, the negative effects of mining in the region, and the corruption of officials. Scientists’ statements about their intention to drill down to bedrock may have also created concerns about covert efforts to develop mining. Flights of helicopters over Musho likely also contributed to speculation about the expedition and its purpose.
Gabrielli described how the research team was grateful for a visit from the president. He added that it was possible the visit put the expedition on locals’ radars for the wrong reasons. “This event put also our activity on the spot of the local population from the village of Musho and other communities,” he said. “They concluded that our ice core drilling activity was part of a business agreement between us and the Peruvian government to extract minerals such as gold and silver from Huascaran, heavily impacting this mountain,” he told GlacierHub.
Thompson offered another possible explanation for the events. “According to the general overseeing the operations, instigators were being paid to cause our Huascaran project to fail since the President of Peru had endorsed the project,” he stated.
Valdivia said, “Reading this situation as a case in which the locals ‘confused’ this scientific expedition with a mining operation is too simplistic.” He suggested that outreach activities to inform Peruvians of the expedition were more focused on national and urban audiences than on the local rural populations.
The solution that was reached rested on establishing a dialogue with the locals who objected. Valdivia suggested that if the locals had been fully informed of the expedition and its purpose, there might not have been a conflict.
Similarly, Kutuzov ended his statement to GlacierHub by saying, “We’d like to thank everybody who was helping us in Peru, president of Peru Martín Vizcarra, president of the INAIGEM Gisella Orjeda Fernández, all the authorities, the people of Musho, and all the communities for allowing us to successfully complete the project.” His comment highlights the important role that communication played in resolving the conflict.
Thompson highlighted the complexity of the environment they were working in, saying “the important thing to understand is that we are the outsiders and do not and cannot fully appreciate the history and the culture and that we need to find a way to work through these issues as they arise.” He added, “the Huascaran project was one of the most successful of my career for which I credit an excellent international field team with an array of diverse talents, great team of mountain guides and porters, local support from friends and colleagues at INAIGEM, the Minister of Environment and the President of Peru, Mr. Martin Vizcarra, and indirectly, the people of Musho!” Thompson was invited back to the region to give lectures on the findings of the expedition.
Despite the successful conclusion of Thompson’s expedition, the elements of discord that originated long before the researchers arrived—and which erupted in a dramatic fashion when they entangled with the project—seem to have returned to a simmer. The sudden and suspenseful turns near the end of the expedition might well bubble up again should the ingredients for conflict combine once more.
This week’s Video of the Week features newly developed drone technology that allows scientists to capture high-resolution video footage and photographs at peak elevations in the Peruvian Andes. The lightweight drone can reach up to 6000 meters above sea level, which was once unreachable due to the air’s thinness. The creator of this innovative drone is scientist Oliver Wigmore from the University of Colorado. Wigmore uses his drone footage to create detailed models of glacial surfaces and document how glaciers are changing over time.
The Carabaya Mountains in the Peruvian Andes contain the largest tropical glacial system, the Quelccaya. As temperatures rise, this region will become increasingly susceptible to landscape changes and vegetation loss. The Carabaya Mountains are home to over 506 vascular plant species. A recent research article documents the immense biodiversity of flora within this region and urges for conservation of tropical mountain systems. Many species are endemic to this mountain range, meaning they’re only found here.
Some research photos of the diverse flora are shown below.
Bill Gentile, an independent filmmaker and American University professor, has recently released a short documentary film, “Fire and Ice on the Mountain.” The film was produced on assignment for American University’s Center for Latin American and Latino Studies and investigates the connections between religion and climate change in Peru.
For the research, Gentile teamed up with Karsten Paerregaard, a Danish anthropologist who has studied Peru for the past 30 years. Together, they explore how the ongoing retreat of Huaytapallana Glacier, located near the city of Huancayo in the central highlands of Peru, affects the local people’s worldview, based on Andean cultural traditions, with particular emphasis on their spiritual relationship with nature and Pachamama (Earth Mother).
GlacierHub interviewed Bill Gentile and Karsten Paerregaard about the film to find out more about how climate change is forcing locals to adapt their traditions.
GlacierHub: Was the local community in Huancayo accessible and willing to share their thoughts on the changes they observed in the glaciers? Were they willing to discuss their religious beliefs?
Karsten Paerregaard: We were well received in Huancayo… Huancayo’s Catholic Church showed great interest in the video and took its time to introduce us to its work. The same happened when we visited the regional government in Huancayo and Pedro Marticorena, the laya mayor [head shaman] on his premises. People are generally keen to discuss the city’s environmental problems. Many are also pleased to relate these to religious issues even though they do not always agree on how religion and climate change are linked.
GH: How is the glacier important in the communities’ traditional practices and religious beliefs? What does it represent?
KP: Glaciers are critical to not only the city of Huancayo but also the neighboring rural communities. This is because they provide them with fresh water, as well as they symbolize the Apus (the mountain deities) whom the local believe control the water flow.
Glacier melt is a physical sign of a rapidly changing nature that causes widespread concern in the city, which is experiencing contamination in many respects: traffic, mining, garbage, etc. However, exactly how glacier retreat, water scarcity and pollution are related is a very contested question in Huancayo. Only a few attribute it to global climate change, and many believe that it is human activities that are causing the city’s environmental problems.
GH: How has the connection with the glaciers developed?
KP: Glaciers have always been there, and as such, they are seen as symbols of the Apu’s powers. Nevertheless, recently people have become concerned about the avalanches they occasionally cause— the last big ones took place in the early 1990s— and currently they are worried that they will disappear altogether. From being a symbol of respect and fear, they have now become an issue of concern and compassion.
GH: How do Andean worldviews express themselves in the daily life of people in the region?
KP: Generally, people are rather syncretic in their religious belief, sometimes tapping into the Andean worldview and sometimes into Catholicism, but more recently the former has gained momentum. This is partly related to glacier melt and the concern for its consequences for Huancayo and partly to the growing feeling of insecurity and uncertainty about the future.
Many visit the mountains to ask Apus for favors in their personal lives, but at the same time, people are becoming aware of the impact of their own actions on the environment and, in particular, the glaciers. This creates confusion about the mutual relationship between humans and nature, which prompts people to review fundamental aspects of their religious beliefs.
GH: Why do you think the regional government is limiting the pollution in the Huaytapallana glacier? Do you think this is influenced by religious groups?
KP: Huaytapallana has been declared a protected area by the national government and it is the regional authorities’ responsibility to implement the regulations associated with its status. The different regional governments have tried to do this with varying degree of success.
Bill and I were impressed by their commitment, particularly by the young woman (Vanessa) who is currently responsible for protecting the environment of Huaytapallana. Regardless of the resistance she encounters from people visiting the glacier, including those who participate in the annual celebration of the Andean New Year at the foot of the glacier.
GH: How do you think the religious practices and festivities will be affected when the glacier retreat is even more advanced than it is?
KP: Glacier retreat attracts more people every year, which suggests that climate change is an issue of serious concern in Huancayo. Nonetheless, the growing number of participants is also a reason for concern.
Bill and I noticed that Pedro Marticorena, as well as some of his followers, are becoming more aware of the impact their activities are having on the glacier. Eventually, they have to modify these and adapt their religious practices and beliefs to the changing environment.
GH: What was the biggest challenge in making the film?
Bill Gentile: The biggest challenge facing the project was finding characters who can help transmit important information from the field to the audience. I was lucky to be working with Karsten, who had the patience to put up with a person (me) pointing a camera at him and asking questions all day. He is a gold mine of information and is articulate enough to convey that information in a compelling way… In addition, and as Karsten points out, the many Peruvians whom we met on our journey were welcoming and generous with their time.
GH: How has the film been received?
BG: American University’s Center for Latin American and Latino Studies (CLALS), which funded my trip, was delighted with the way the film explains the issue of religion and climate change in Peru.
The Pulitzer Center on Crisis Reporting published a piece on “Fire and Ice on the Mountain” on its website because it addresses the “under-reported, systemic issues” that the Pulitzer Center is most concerned about. I have been using the film in my classes as a teaching tool. Students and colleagues find it inspiring.
GH: What plans do you have for the film?
BG: I will be entering some film festivals and will continue to use it as a teaching tool.
GH: What is your greatest satisfaction in having made this film?
BG: As with any of the films I have made, my deepest satisfaction is taking part in the global conversation that we call “journalism.” I am lucky and privileged to be able to travel, to seek truth, to create, to meet fascinating people, to explore their lives and to communicate their reality to people in other parts of the world.As you know, we live in a time when truth is under attack. I take great pride and even greater satisfaction in defending it.
On August 7th, in light of the rapid retreat of glaciers in the Andes, two Peruvian national organizations subscribed to an inter-institutional cooperation agreement to implement a glacier research center in the Peruvian city of Cusco. The agreement between the National Research Institute for Glaciers and Mountain Ecosystems (INAIGEM by its acronym in Spanish), the leading glacier research institution in the country, and Cusco’s San Antonio Abad National University (UNSAAC in Spanish) aims to strengthen the scientific agenda for glaciology-applied research in the southern Andean region of the country.
INAIGEM’s Macro Regional Office of the South will be located in Kayra Estate, a meteorological agricultural experiment station founded in 1956 and managed since then by UNSACC. This office will coordinate research projects all over the southern region of Peru. Thus, INAIGEM will provide technical assistance to regional governments to develop appropriate policies in biodiversity, water resources, food security and glaciers, within the context of climate change.
Benjamin Morales, executive director of INAIGEM, stated during an interview for UNSAAC that for students from the university, the glacier research center will be a learning space where they will be able to investigate with expert researchers. Students from different faculties including geology, geography, biology and other social and environmental sciences will be able to participate in the research projects that the INAIGEM will develop in Cusco in the following months.
During an interview with Glacierhub, Morales highlighted the community approach to conducting research, as the institute is coordinating with regional and local governments, the private sector, and universities in each city of the Southern Andes. As the Peruvian online information portal Inforegion indicates, scientists are currently monitoring two important mountains near Cusco: Mount Ausangate, the fifth-highest mountain in Peru, and Chicón, relevant for its water supply to the Cusco region. Scientists are also monitoring neighboring areas between Cusco and Puno, part of the southern region of Peru on the border of Bolivia. INAIGEM will start a study at the Coropuna glacier in the region of Arequipa, for example. Coropuna, one of the highest mountains in Peru, is facing rapid glacier retreat due to climate change.
Mark Carey, a professor at the University of Oregon, told Glacierhub in an interview that partnerships between different types of institutions can effectively enhance glacier-related work in the Andes and beyond by combining the study of ice and society. They are an effective means of drawing together the natural and social sciences, as well as researchers and local communities, in an equal partnership of exchange and interaction.
Due to the direct relationship between glaciers and society, the partnerships with local communities in the southern Andes allow researchers to understand how glacier retreat is affecting cultural values, agricultural practices and the economy. Moreover, in several regions, local populations understand the changes that are produced by the natural Andean climate variability and have implemented their ancestral knowledge to adapt to those changes. An example of this is the local community of Vilcabamba, located in Cusco, has implemented an agricultural system similar to a terrace that was used by the Incas to increase the amount of cultivatable land available to farmers due to the reduction of water supply from Salkantay glacier, located on the twelfth highest mountain in the country.
It is important to have continuing research on glaciers in the Andes to contribute to the understanding of the future natural changes. In a country that traditionally encouraged the centralization of resources and areas of study in the capital city of Lima, institutes like INAIGEM are now supporting a decentralization process. Unlike most Peruvian national institutions, for example, INAIGEM is headquartered in Huaraz, a mountain city located at the base of the Cordillera Blanca. Furthermore, it has as an objective to promote and strengthen the environmental agenda and technological development in the Peruvian Andes, an area sometimes forgotten by Peruvians.
As Carey told Glacierhub, while the Cordillera Blanca is the most glacierized range in Peru (and in fact the most glacierized range in all of the world’s tropical regions), glaciers in the south of the country have been understudied in the last decades. In Carey’s opinion, the Macro Regional Research Office of the South will widen the glacier research that Peruvians have been conducting in the Cordillera Blanca for more than half a century. In developing countries such as Peru, the effects of glacier retreat greatly impact neighboring areas. For example, when glacier runoff from Cusco-area glaciers declines, it changes the hydroelectric output from the facilities of the Machu Picchu Hydroelectric Station.
Thus, Luis Vicuña, a researcher at the University of Zurich, explained in an interview with Glacierhub that there is a direct relationship between glaciers and society. “A wider understanding of the future of glaciers in our society implies research that involves different types of expertise in order to contribute to the understanding of the natural and physical changes, and also the cultural, political, economic and social changes that will determine the relationship between glaciers and society.”
Multi-stakeholder engagement and collaboration can effectively enhance glacier-related work in the Andes and beyond. The cooperation agreement between INAIGEM and UNSAAC plans to facilitate the articulation of environmental scientific research with policy-making processes that regional governments need to support local communities in adapting to climate change.
The Economist: “Venezuela is a tropical country, with rainforest in the south and east, and baking savannah stretching towards its northern Caribbean coast. The Sierra Nevada de Mérida mountain range in the north-west offers relief from the heat. In 1991 five glaciers occupied nooks near their peaks. Now, just one remains, lodged into a cwm west of Pico Humboldt. Reduced to an area of ten football pitches, a tenth of its size 30 years ago, it will be gone within a decade or two. Venezuela will then be the first country in the satellite age to have lost all its glaciers.”
Read more about Venezuela’s Humboldt Glacier here.
Small-Scale Farmers’ Vulnerability in the Peruvian Andes
From Iberoamericana: “Previous studies have shown that climatic changes in the Peruvian Andes pose a threat to lowland communities, mainly through changes in hydrology. This study uses a case study approach and a mixed qualitative-quantitative method to examine the vulnerability of small-scale farmers in the Quillcay River basin to variations in precipitation and enhanced glacier retreat. The findings of the study show partly contradicting results. On one hand, interpretation of semi-structured interviews suggests a strong relation between climate proxies and increased vulnerability of the smallholders. On the other hand, in the quantitative analysis enhanced glacier retreat seemed to have augmented vulnerability solely to some extent whereas precipitation did not show significant impact.”
Learn more about climate change in the Peruvian Andes here.
A Glacier-Permafrost Relationship in Sweden
From Quaternary Research: “Here, we present empirical ground penetrating radar (GPR) and electroresistivity tomography data (ERT) to verify the cold-temperate transition surface-permafrost base (CTS-PB) axis theoretical model. The data were collected from Storglaciären, in Tarfala, Northern Sweden, and its forefield. The GPR results show a material relation between the glacial ice and the sediments incorporated in the glacier, and a geophysical relation between the ‘cold ice’ and the ‘temperate ice’ layers…The results show how these surfaces form a specific continuous environmental axis; thus, both glacial and periglacial areas can be treated uniformly as a specific continuum in the geophysical sense.”
In the Cordillera Blanca Mountains of the Peruvian Andes, glacier retreat caused by climate change has led to an increased risk of flooding for residents living below. Saúl Luciano Lliuya, a farmer and mountain guide who faces the imminent threat of losing his house in a massive flood, argues that large polluters are to blame. This led him to file a lawsuit against the German energy giant RWE demanding the firm take responsibility for its CO2 emissions and help reduce the risk of flooding.
The lawsuit could set an important precedent – if Luciano Lliuya wins, anyone affected by climate change impacts could potentially sue for damages or compensation beyond the borders of their own country. This may provide a more fruitful strategy in light of stalling political efforts at the United Nations level to combat climate change and promote adaptation. In December 2016, the lawsuit was dismissed by the Essen Regional Court in Germany and is currently pending appeal.
Climate Change in the Cordillera Blanca
Growing up below the snow-capped mountains of the Cordillera Blanca, Lliuya has borne witness to a changing Andean climate over the past decades. Now aged 36, his work as a mountain guide brings him to high altitudes where he has observed the glaciers progressively receding year after year. This led the glacial lake Palcacocha to rise exponentially in volume – from 0.5 million m3 in 1974 to 3.9 million m3 in 2003 and 17.4 million m3 in 2016. A dislodged piece of glacial ice falling into the lake could lead to a massive outburst flood that would destroy large parts of the city of Huaraz below, according to a recent scientific study.
Huaraz is no stranger to disaster. In 1941, Lake Palcacocha produced an outburst flood that killed thousands and devastated the city. In subsequent decades, the Peruvian authorities drained Palcacocha and other glacial lakes, constructing dams to prevent future disasters. Residents of Huaraz rebuilt the city. Today, existing dams and drainage systems are no longer sufficient at Palcacocha as glacial retreat has increased dramatically and authorities struggle to fund security measures after neoliberal cuts to public finance since the 1990s.
In the short term, glacial retreat in the Cordillera Blanca causes the threat of too much water flooding populated valleys. But if glaciers disappear in the long term, the region will lose its primary source of water. Both scenarios can have devastating consequences. In addition, residents face an increasingly unpredictable climate that disrupts agricultural cycles.
Lliuya argues that Peruvians have contributed little to these problems. “The big companies are mainly responsible for climate change through their emissions. They need to take responsibility and help us face the problems they caused,” Lliuya told GlacierHub. He wanted to take matters into his own hands. When a colleague put him in touch with members of the German environmental NGO Germanwatch, he found partners who were willing to help him take action. Introducing him to the German environmental lawyer Roda Verheyen, the NGO offered to support a legal claim for climate justice against a major polluter. In November 2015, he traveled to Germany and filed a lawsuit against RWE, the largest single CO2 emitter in Europe.
“This is a precedent. RWE AG releases significant emissions, principally through its coal-fired power plants, which makes global temperatures rise, causes glaciers to melt and leads to an acute threat to my client’s property,” Verheyen argued. “We request that the court declare RWE liable to remove this impairment.”
The lawsuit relies on article 1004 of the German Civil Code to argue that RWE is partially responsible for the impairment that Luciano Lliuya faces to his property through climate risk. Drawing on the Carbon Majors study which quantified industrial greenhouse gas emissions and linked them to individual companies, the lawsuit states that RWE contributed 0.47% to historical emissions and should provide its share to reduce flood risk in Huaraz. The Peruvian authorities are planning a multi-million dollar project to drain Lake Palcacocha and build a new dam. Lliuya demands that RWE pay 0.47% of this amount, or around $20,000. The amount is miniscule for a large company but could set a massive precedent.
RWE rejects the claim, arguing that climate change should be discussed at a political level rather than in the courts. In its legal response, the company claims that climate change is so complex that individual companies cannot be linked to specific impacts. In addition, the company denies that Huaraz faces an imminent risk of flooding. RWE did not reply to GlacierHub’s request for comment.
In December 2016, the Essen Regional Court dismissed Lliuya’s lawsuit on formal grounds, stating that his claims lacked legal foundation and coherence. In their verdict, the judges argued that RWE may have partially caused the risk of flooding in Huaraz in scientific terms, but this does not translate into causality in legal terms.
“The pollutants, which are emitted by the defendant, are merely a fraction of innumerable other pollutants, which a multitude of major and minor emitters are emitting and have emitted. Every living person is, to some extent, an emitter,” reads the finding.
Following the judges’ argumentation, individual polluters cannot be held responsible for climate change because emissions are so widely dispersed. While RWE welcomed the verdict, Lliuya is defiant and vowed to continue. His lawyer is currently preparing an appeal.
The lawsuit is the first of its kind to come this far, but it could set the stage for future climate justice initiatives. In glaciated mountain ranges around the world, people face increased threats of flooding. Even if Lliuya’s lawsuit fails upon appeal, it forms part of a larger trajectory of legal initiatives that demand immediate action while political solutions remain stymied. In the United States, Our Children’s Trust supports lawsuits by children and teenagers against local and federal authorities demanding more sustainable policies. In the Netherlands, the Urgenda citizen’s initiative successfully sued the Dutch government demanding more ambitious climate targets in a suit that is currently pending appeal.
In the long term, Lliuya hopes lawsuits against large polluters will create political pressure to find sustainable solutions to the impacts of climate change. These solutions should account for the historical responsibility of companies such as RWE. Only few people have the means to take legal action; a sustainable strategy must benefit all. As long as policy makers fail to make polluters pay, Lliuya will continue his legal battle against RWE.
“The biggest contributors to climate change must finally take responsibility,” he said. “I want justice.”
From Science of The Total Environment: “Quantifying fluxes [the action of flowing] of water, sediment and dissolved compounds through Arctic rivers is important for linking the glacial, terrestrial and marine ecosystems and to quantify the impact of a warming climate… This study uses a 8-years data set (2005–2012) of daily measurements from the high-Artic Zackenberg River in Northeast Greenland to estimate annual suspended sediment fluxes based on four commonly used methods: M1) is the discharge weighted mean and uses direct measurements, while M2-M4) are one uncorrected and two bias-corrected rating curves extrapolating a continuous concentration trace from measured values.”
From Applied Geography: “Receding mountain glaciers affect the hydrology of downslope ecosystems with consequences for drinking water, agriculture, and hydropower production. Here we combined land cover derived from satellite imagery and other environmental data from the northern Peruvian Andes into a first differencing regression model to assess wetland hydrologic connectivity… The results indicate that there were two primary spatial driving forces of wetland change in Peru’s Cordillera Blanca from 1987 to 1995: 1) loss in glacier area was associated with increased wetland area, controlling for other factors; while 2) an increase in mean annual stream discharge in the previous 12 months increased wetland area.”
Observation-Based Estimates of Glacier Mass Change
From Surveys in Geophysics: “Glaciers have strongly contributed to sea-level rise during the past century and will continue to be an important part of the sea-level budget during the twenty-first century. Here, we review the progress in estimating global glacier mass change from in situ measurements of mass and length changes, remote sensing methods, and mass balance modeling driven by climate observations. For the period before the onset of satellite observations, different strategies to overcome the uncertainty associated with monitoring only a small sample of the world’s glaciers have been developed. These methods now yield estimates generally reconcilable with each other within their respective uncertainty margins. Whereas this is also the case for the recent decades, the greatly increased number of estimates obtained from remote sensing reveals that gravimetry-based methods typically arrive at lower mass loss estimates than the other methods. We suggest that strategies for better interconnecting the different methods are needed to ensure progress and to increase the temporal and spatial detail of reliable glacier mass change estimates.”
Glacier retreat, as an easily observable consequence of climate change, also embodies spiritual significance to local communities. In some cases, local perceptions of glacier melt differ from that of the scientific community.
In a new paper, Elizabeth Allison of the California Institute of Integral Studies, San Francisco, looks at three instances of glacial decline in sacred mountain landscapes—in the Peruvian Andes, the Nepalese Himalayas, and the Meili Snow Mountains of Yunnan, China — and observes how different cosmologies provide different accounts of the rapidly melting ice. She found that the ways in which communities perceive glacier melt also affects the way these communities interact with their traditions and with glaciers themselves. Her work suggests the value of broadening the discussions of climate change in modern urban societies as well, by showing the depth of human engagement with the natural world–and, more broadly, by showing that people everywhere seek meaning from nature.
The Peruvian Andes
In the Peruvian Andes, the local residents, the Quechua, believe that the declining glacier is associated with the departure of the mountain god. In their worldview, the mountain gods bestow vitality on plants and animals and are thus worshipped as a manifestation of Mother Earth.
The local residents have long observed the recession of the mountain glaciers. They believe that their mountain gods have always had white ponchos, but some of their ponchos have brown stripes now. It is a mystery to the Quechua what they have done to irritate the mountain god who is limiting water flow.
Concern for the declining glaciers has led to changes in local rituals and customs. Strict regulations have been in effect to prevent anyone from removing ice, and only small bottles of meltwater are allowed to be collected. Guards are also positioned at the edge of the glacier. Pilgrims who used to light candles while seeking answers for their concerns along the edge of the glaciers have started to use smaller candles to preserve the glacier.
Furthermore, local prophecy predicted future calamity when the world will end after the glacier is gone. Local people believe when the glacier disappears, wind will blow everything away and a new epoch will thus begin.
The Nepalese Himalayas
In the Himalayas, it is believed that gods reside on mountaintops to distance themselves from the filth of human life. Sherpas, like the Quechua, sometimes link the decline of mountain glaciers to gods or deities.
Some of them see it as a moral reprimand by the gods due to the departure from traditional lifestyle to new lifestyles that generate pollution. Some Sherpas invoke both scientific and religious interpretations to explain melting glaciers, including changing weather variability, weakening belief in gods and spirits, etc.
In Tibetan Buddhist societies of Nepal, Ladakh, and Bhutan, activities that upset the boundaries between social groups or substances, including cooking or eating garlic and onions, burning meat, experiencing strong emotions, breaking vows, can be the source of physical or spiritual pollution.
Local residents are trying to prevent the pollution of mountain peaks in fear of releasing the fury of mountain gods.
Meili Snow Mountain Range
The Mingyong Glacier below Mount Khawa Karpo in the Meili Snow Mountain Range in Northwest Yunnan, China, is one of the most rapidly receding glaciers in the world. From 2002 to 2004, the Mingyong Glacier retreated around 110 meters, and a total of 2.3 kilometers from 1870 to 2004, according to local stories.
A local Buddhist monk suggested that the glacier retreat resulted from insufficient devotion on the part of Buddhists, because outside visitors failed to demonstrate highly reverent behavior around the holy mountain. Others blame the use of electricity and increasing material greed.
Allison believes that the local interpretations that blame lack of reverence for glacier decline reflect larger social, political, and scientific trends that have provided anthropogenic conditions for glacier recession.
Glacial decline, as Allison suggested, is not only a physical and observable process caused by climate change, but also has bearing on how local people understand themselves and interpret the environment they rely upon. Different values stem from different experiences of the landscapes, which reflect the implications of climate change.
Community-based adaptation strategies are essential for dealing with drought in the Peruvian Andes, according to a new study by Ralph Lasage et al. published in Sustainability.
Over 80% of residents in the Peruvian Andes rely on agriculture as a major source of income and are highly dependent on the availability of water resources. But in the past, droughts associated with El Nino events have been devastating for these communities and led to increased migration from rural areas to cities. According to Ralph Lasage and a team of researchers from VU University Amsterdam and Amsterdam University College, the drought of 1982 resulted in 60% – 70% reduction in highland agricultural production.
And water availability in the Andes is set to continue to decline as glaciers recede. Effective water management systems and adaptation measures on the local scale play significant roles in reducing the impacts of climate change on the glaciers thousands of people rely on, Lasage and his team found.
When glaciers melt, the risk of outburst floods increases dramatically. In 1941, the glacial lake Palcacocha in the Peruvian Andes burst and tons of water crashed into the city of Huaraz, killing around 5,000 people. In the following decade, two more glacial lake outburst floods (GLOFs) occurred in the Cordillera Blanca in north-central Peru due to excessive water released when glacier moraine dams failed. To address the issue, the Peruvian government strengthened terminal moraine dams, sophisticated valve systems, and drain pipes to prevent extensive damage when future GLOFs occurs. In addition, it initiated glaciological unit, which helped prevent many outburst floods and significant fatalities.
However, outburst flooding is not the only glacier melt-related issue that concerns Peruvians. Droughts associated with climate variability, which threaten the country’s water supply, pose a major concern for residents of the South American nation. Shrinking glacier volume during this century is projected to intensify. But hydrological data gaps limit scientists’ ability to understand cycles of flooding and droughts. it is difficult for them to assess vulnerability to floods and droughts on regional level.
Through their study, Lasage and his team presented a stepwise participatory approach to create a vulnerability index and develop community-based adaptation measures. The study was conducted in the Chorunga catchment, which is “representative of the environmental and socio-economic conditions of farming communities across the Andes”. They found that improving the efficiency of water usage and storage was a bigger challenge for communities than creating water storage at high elevations close to glaciers.
The Chorunga catchment, which is part of the Ocona River basin, is a poor rural area where roughly “68% of the population live in poverty, compared with 14% for the whole of Peru”. Located in the south of the Cordillera Blanca, the Chorunga catchment received the majority of its water irrigation comes from the Coropuna Glacier, which lost 37% of its total volume and has been rapidly retreating, in the form of melting glacier water. In addition, the team conducted in-depth study of the functioning of the villages’ irrigation systems and the governance of water resources. Perceived vulnerability was evaluated alongside a variety of socio-economic characteristics of the respondents, including income, education, access to water, and etc.
Lasage and his team started by gathering information on local households’ perception of their vulnerability to droughts and the effectiveness of proposed adaptation strategies through questionnaires and face-to-face interview in the Chorunga catchment. The vulnerability index was defined as the product of “exposure” (or frequency of drought periods) and “sensitivity” (or perceived impacts of a drought on people’s livelihoods) divided by “response efficacy” (or perceived effectiveness of adaption measures in response to reduced water availability). In addition, the team gathered information on the governance of water resources as well as irrigation systems through in-depth interviews with government offices, NGOs, and local colleges. More importantly, the team collaborated with a variety of Peruvian stakeholders (e.g. local farmers, Water Associations, Irrigation Commissions, and etc.) and initiated several possible adaption measures. Ultimately, some adaption measures were selected on the basis of climate projections and investment costs.
Glacier recession has been accelerating since the 1970s, which will likely lead to the disappearance of the glaciers. As a result of rising temperatures, a large portion of the precipitation comes in the form of rainfall instead of snow. Therefore, water availability is anticipated to decline during growing season for crops on the long run even though increased melting glacier water will slightly contribute to water runoff in the short term. In other words, additional melt-water from glacier retreat will not make a difference in increasing discharge, because the effect of reduced precipitation due to high temperatures will most likely be overwhelming.
The vulnerability analysis reveals that households with a larger area of irrigated land tends to be less vulnerable to droughts; households with lower income are more vulnerable but less willing to adapt to climate change; and people with a higher education appear to be less sensitive to drought and willing to cope with adaptation measures. There is a strong correlation between households’ water availability and their vulnerability to droughts.
The selected adaptation measures concentrated on improving the efficacy of water usage and storage in the Chorunga catchment. In particular, surface dams were constructed to store rainfall during the wet season, and to be used during the dry season. Low-cost gravity drip irrigation systems and water-efficient crops were introduced to maximize crop production in the fields with limited amount of water. In addition, roof-water harvesting systems were installed to increase useable water. Generally speaking, the implementation of such adaptation measures will possibly increase households’ water availability during the dry season, and hence reduce their vulnerability to droughts.
“The stepwise approach proved to be suitable to structure the process of developing and implementing adaptation measures jointly with a wide range of stakeholders in a rural area in Peru. It enabled the inclusion of information ranging from the local to the global scale and led to the joint implementation of several community-based measures”, said Lasage et al.