Bushfires raging in Australia have taken their toll on New Zealand’s glaciers. Smoke and dust from the fires drifted across the Tasman Sea and settled on glaciers in New Zealand approximately 4,000 miles away. Ash covering glaciers in New Zealand is visible in photos published to Twitter. In the images, the snow and ice appears as a pinkish color.
Australia has experienced a particularly severe bushfire season, with multiple lives lost, homes destroyed, and over one million hectares of land burned. The smoke and dust-laden glaciers of New Zealand are representative of the second-order effects of the bushfires in Australia.
The distance the smoke and ash have traveled and the extent to which they have blanketed glaciers in New Zealand speaks to the severity of the Australian bushfires. This coating of smoke and ash poses a significant threat to New Zealand’s glaciers. It settles as black carbon, which darken glaciers’ snow and ice, absorbing heat and contributing to increased rates of melting and extending the melt season.
Glaciers are not only an integral component of mountain ecosystems in New Zealand, but they are major draw for tourists visiting the island. Glacier retreat in New Zealand is reshaping the country’s tourism industry. In October, GlacierHub covered the growing concern over melting glaciers in Aoraki/Mount Cook National Park in New Zealand.
The pink hue of New Zealand’s glaciers is not only a grim reminder of the devastating fires burning in Australia, but also makes visceral the threat of melting glaciers. Unfortunately, as Australian bushfires continue to blaze, New Zealand and its glaciers may continue to experience residual effects.
Researchers in Canada have discovered that proglacial freshwaters are important carbon sinks. Glacier retreat has often been considered a negative consequence of climate change, but this finding suggests there may be benefits as well.
The study published on September 3 in the journal Proceedings of the National Academy of Sciences, was conducted in Nunavut, Canada, home to Lake Hazen, the world’s largest Arctic lake. Lake Hazen is fed by rivers, which flow from glaciers within the Northern Ellesmere Icefield. The icefield is located on Ellesmere Island, the world’s tenth largest island. Ellesmere Island is home to polar bears, muskoxen, caribou, and most interestingly, thirteen species of spiders.
The results of the study revealed that glacier-fed rivers consume more carbon dioxide than they release into the atmosphere. The carbon dioxide concentrations of all seven glacial rivers sampled were found to be below atmospheric equilibrium at all but one sample site. This result indicates that the rivers are storing carbon from the atmosphere.
Kyra St Pierre is a research associate at the Institute for the Oceans and Fisheries at the University of British Columbia, and lead author of the study. “Glacier-fed rivers differ quite substantially from other rivers because they’re very cold, are located in landscapes without a lot of plant material (i.e., organic carbon), but with a lot of finely ground sediments created by the successive cycles of glacier advance and retreat,” St Pierre told GlacierHub. “Because the landscapes lack things that would otherwise constrain the flow of a river, like trees or well-developed soils, glacier-fed rivers reorganize themselves regularly and in so doing, entrain a lot of finely ground sediment in the rivers.” It is because of these unique characteristics of proglacial rivers and the chemical weathering process associated with them that they can act as carbon sinks.
Researchers collected water samples from Lake Hazen and seven glacial rivers within the Lake Hazen watershed. With these samples, researchers measured changes in river chemistry and carbon dioxide fluxes during the summers of 2015 and 2016. Samples were collected in summer when glaciers were melting rapidly.
The researchers discovered that the weathering process initiated reactions between minerals within the sediment. The process that dominated in the sampled rivers was one that consumed carbon dioxide. Researchers noted that carbon dioxide concentrations decreased with distance from the glaciers, while dissolved inorganic carbon concentrations increased. Dissolved inorganic carbon is a main component of inland waters and influences organic productivity.
“The concentration of carbon dioxide within the rivers declines as these reactions proceed,” St Pierre said. “The difference between the carbon dioxide concentration in the waters (low carbon dioxide) and the atmosphere (high carbon dioxide) increases, such that more carbon dioxide from the atmosphere moves into the rivers and is then consumed. Chemical substances will always try to move from areas of high concentrations to areas of low concentration in an attempt to find a ‘“balance’” or equilibrium.”
St Pierre also told GlacierHub that most rivers across the globe are sources of atmospheric carbon dioxide, which is released through photosynthesis and decomposition of aquatic plants. For this reason, the discovery of proglacial freshwaters as carbon sinks was initially a surprise to researchers.
Researcher Martin Sharp first proposed the idea of proglacial freshwater carbon sinks in an article in 1995. Sharp was a member of the research team and co-authored the journal article with St Pierre. St Pierre and her colleagues have worked in the Lake Hazen watershed for nearly 15 years. They were inspired to develop this study when they began testing water quality parameters of the glacier-fed rivers connected to Lake Hazen. It was by testing the river water temperature and chemical composition, that they first noticed that carbon dioxide concentrations were not what they expected.
Before their study, carbon dioxide concentrations had not been directly measured within glacier-fed systems, making this study ground-breaking. However, there is evidence from related research that supports the findings of this study. Data from study sites in Greenland, Svalbard, central Europe, and western Canada suggest carbon dioxide consumption by proglacial freshwaters is not isolated to the Lake Hazen watershed, but might also be relevant in other regions of the globe. St Pierre said, “In the past, we’ve always thought of freshwater systems as being sources of CO2 to the atmosphere, but these findings suggest that there’s a lot more nuance that needs to be accounted for.”
This research is somewhat of a conundrum for climate scientists. Carbon is a major driver of global climate change and carbon sequestration is viewed as significant for climate mitigation. However, the environmental benefits of glacier-fed rivers consuming more carbon dioxide than they emit to the atmosphere come at the cost of melting glaciers. Climate change and melting glaciers result in sea level rise and change the temperature and salinity of oceans. Ultimately, more research must be done to fully weigh the positive and negative effects of this process.
Carbon cycling between proglacial freshwaters and the atmosphere also influences aquatic ecosystems. Sediments transported by glacial rivers are an important contribution to freshwater and marine ecosystems. St Pierre explained, “In lake environments, these sediment-laden rivers can also form turbidity currents, which transport lots of sediment and terrestrial materials, but also waters with low concentrations of carbon dioxide and high concentrations of oxygen directly to the bottom of the lake. Lake bottoms typically have low oxygen and high carbon dioxide concentrations, so this is an important downstream impact for organisms at the bottoms of glacial melt-affected lakes.”
There is much more to learn about proglacial freshwater carbon sinks and this study is just the beginning for this research subject. St Pierre’s colleagues from the University of Alberta are continuing this work with a study that began in the summer of 2019 that will examine proglacial rivers and lakes in Banff and Jasper National Parks in the Canadian Rockies.
One of the largest glaciers in the Tergi River basin in Georgia is retreating drastically and there’s a GIF to prove it. This month, Levan Tielidze, a senior research scientist at the Institute of Geography at Tbilisi State University and Ph.D. student at Antarctic Research Centre, Victoria University of Wellington, created a 3D map depicting the retreat of the Gergeti Glacier from 1882 to the present. This 3D map, or GIF, is the first of its kind from the Georgian Caucasus.
The Gergeti Glacier lies within Kazbegi National Park in the Georgian Caucasus. Here, glaciers play a vital role in the ecology and economy of the region. They provide a freshwater source that feed rivers in the area. This water from glaciers is essential to river ecology, particularly during the summer months when rivers have lower flows. Without this source of water, the region would be left drier and more vulnerable to wildfires. Glacier retreat is also a threat to local economies. Tourism is important to the area, as glaciers within the National Park draw thousands of visitors annually. If the number of visitors declined significantly, it would result in economic consequences. Consequences that would ripple throughout the economy, beginning with those whose livelihoods depend on tourism.
Tielidze explained to GlacierHub how he developed the 3D map stating, “I used old topographical maps and satellite imagery to measure the perimeters of the glacier. The animation data shows that the Gergeti Glacier has been strongly reduced in the area since 1882.” According to Tielidze, this glacier lost 42 percent of its area between 1882 and 2019 with its front retreating nearly 3 km.
The GIF created by Tielidze opens with an early image of the Gergeti Glacier followed by four other snapshots from the last six decades. As can be seen in the GIF, the size of the glacier in 1882 is drastically different from its size today. This visualization shows the severity of glacier retreat in the Georgian Caucasus over the last 137 years. Tielidze also used his research to associate climate change with temperature trends in the period 1907-2009. His results suggest that rising temperatures have enhanced glacier retreat in the Georgian Caucasus, like that of the Gergeti Glacier.
Georgia contains 700 glaciers, all of which are affected by climate change. Tielidze warned that “if the increase of the temperature and decrease in the surface area of glaciers in the eastern Greater Caucasus continues over the 21st century, many will disappear by 2100.”
Considered a treasure of the United States, national forests draw millions of visitors each year. Today, one of the United States’ 154 national forestshas become a subject of significant controversy due to a recent proposal made by the Trump administration. This proposal recommends expanding logging in the Tongass National Forest in Alaska. In a state known for its vast, untouched wilderness, this proposal has been met with fierce opposition. Environmental awareness has been on the rise in recent decades and many view this proposal as a step in the opposite direction.
Spanning 500 miles, Tongass National Forest is the largest national forest in the United States and contains the world’s largest temperate rainforest. It features mountains, glaciers, old-growth forest, salmon streams and is home to bears, wolves, eagles, and people. Indigenous groups have inhabited the Tongass for over 10,000 years. Approximately 70,000 people live in the Tongass National Forest today. Included in this figure, is the population of Juneau, which is situated within the Forests’ bounds. As surprising as it may sound, the Tongass is not just pristine wilderness, but contains towns and logging areas as well. According to the U.S. Department of Agriculture (USDA), only 8 percent of land in the Tongass is currently developed. However, that may soon change.
Forest management in the U.S. has a long history, beginning in 1876, with the creation of an office of Special Agent, within the USDA, to assess forest conditions across the country. The creation of this office was followed by the Forest Reserve Act of 1891 which allowed the President to create forest reserves. Finally, in 1905, the U.S. Forest Service was created within the USDA, transferring the responsibility of the forest reserves from the Department of the Interior.
A comparatively recent measure, the 2001 Roadless Rule, has further protected 58.5 million acres of land within the National Forest System. This rule protects National Forest System lands from development by road construction, road reconstruction, and timber harvesting. The Trump Administration’s new proposal would exempt the Tongass National Forest from the 2001 Roadless Rule, releasing millions of acres of the Forest from its protection. The proposal, supported by Alaskan Senator Lisa Murkowski, is being publicized as beneficial to the state’s economy.
This October, the USDA published a draft environmental impact statement concerning increased logging in the Tongass. The statement, prepared under the National Environmental Policy Act, outlines various scenarios of logging in the Tongass. The six options detailed in the environmental impact statement vary from no change to the complete removal of the Tongass National Forest from the 2001 Roadless Rule. The preferred alternative would remove 9.2 million acres of land from the protection of the 2001 Roadless Rule and would convert 165,000 acres of old-growth forest and 20,000 acres of young-growth forest from unsuitable timber lands to lands suitable for logging.
This proposal to increase logging in the Tongass National Forest has been met with opposition from environmentalist and indigenous groups. An image from a rally supporting the continuation of the 2001 Roadless Rule greets you on the main page of the Southeast Alaska Conservation website. An entire section of the group’s website is dedicated to “Attacks on the Tongass” and posts urge you to submit a comment to the National Forest Service. Similarly, Women’s Earth and Climate Action Network International (WECAN) and Earthjustice are involved in the Tongass activism. The two groups helped bring together the WECAN Indigenous Women’s Tongass Delegation, which traveled to Washington D.C. in March of this year to protest the logging proposal.
Several indigenous groups live near the Tongass and have deep ties to the land, including the Tlingit, Haida, and Tsimshian Tribes. According to local activists involved with the WECAN Indigenous Women’s Tongass Delegation, increased logging will threaten native culture. The delegation strives to preserve their way of life for future generations. Both indigenous and conservation groups fear the impacts increased logging will have on the natural environment within the Tongass.
Much uncertainty lies in how increased deforestation and development could affect ecosystems, impact water resources, or affect recreation in the Tongass. Freshwater sources in the Tongass provide drinking water and hydroelectric power to surrounding communities. These aquatic ecosystems are particularly vulnerable to land use changes, as they depend on glacier flow, snowmelt, and forest health. Fishing in Southeast Alaska is a source of food, recreation, and income. Rivers within the Tongass are kept clean and cool by large trees, creating conditions that sustain an abundance of spawning salmon. However, increased logging in the Tongass may threaten river conditions and salmon populations.
According to Jason Amundson, a geophysicist at the University of Alaska Southeast, glaciers in the Tongass, like all glaciers across the globe, are melting rapidly. Loss of glaciers would disturb the flow of cool water from snow melt to rivers and streams. This disruption, coupled with increased logging may have significant impacts on rivers and fish populations within the Tongass.
Dr. Amundson believes public opinion of the proposal is mainly negative in Juneau, Alaska. This opposition stems from salmon fishermen and others who want to preserve Alaska’s natural resources. Dr. Amundson explained that the state of Alaska is very resource dependent and different groups can have conflicting uses for these resources. Resource development appeals to some, as it provides jobs, however, others argue development damages the natural environment, which is the main draw for tourists to the state.
Dr. Amundson emphasized the uncertainty of repercussions from increased logging. He believes it to be unlikely that increased logging would have significant impacts on glaciers in the Tongass. Although, he speculated that changes to the landscape could result in changes in temperature, producing local effects on glaciers. Dr. Amundson explained that across the globe, glaciers are generally situated on more barren lands and not in close proximity to forests. Glaciers within the Tongass National Forest differ in this way, as they are located near forested areas. For this reason, increased logging in the Tongass may have a significant impact on the Forest’s glaciers. However, Dr. Amundson stressed that there is not enough research on the topic to accurately draw conclusions.
Dr. Amundson visits the Tongass to perform research on the Forest’s glaciers and for recreational purposes. While the proposal does not directly threaten his research on glaciers in the Tongass, he believes it could impact recreation. He thinks increased logging in the Tongass may impact visitor experience for those who come from out of state.
While there is currently no evidence linking increased logging with damage to glaciers in the Tongass, altering the landscape can influence climate change. Forests act as carbon sinks, absorbing carbon and reducing carbon absorbed by the atmosphere. As a massive temperate rainforest, the Tongass is one of the world’s major carbon sinks. If logging increases, this carbon sink could disappear, which would result in an acceleration of global climate change and impact glaciers in the Tongass and all over the world.
The implications of exempting the Tongass National Forest from the 2001 Roadless Rule are unclear. This uncertainty has heightened fear and distrust of this proposal, particularly because local culture and the Southeast Alaskan economy depend on the Tongass. Seafood harvests, cultural ties and energy production are just several ways Alaskans depend on the National Forest. The Our Forests Are Alaska campaign stresses this connection between communities in Southeast Alaska and the Tongass National Forest.
The Secretary of Agriculture is expected to make a decision regarding the future of the Tongass National Forest in the 2001 Roadless Rule by June 2020. The National Forest Service has scheduled public meetings and the USDA has opened the draft environmental impact statement to the submission of public comments. If you would like to add your voice to the debate, you have until December 17, 2019 at midnight to submit a comment.
Last week the High Mountain Summit, established by the World Meteorological Organization (WMO), convened in Geneva, Switzerland. WMO, an agency within the United Nations (UN) organized the conference to address changes to high mountain ecosystems as a result of rising global temperatures. WMO released a short video detailing the environmental changes occurring in high mountain regions and the importance of adapting to these changes.
Global climate change is threatening high mountain ecosystems, endangering wildlife and human populations alike. Approximately half of the world’s population relies on freshwater sourced from mountain ecosystems. Although, changes to seasonal runoff threatens this freshwater source. Retreating glaciers and changes to precipitation patterns increase the risk of flooding and avalanches. Flooding, avalanches, and lack of available freshwater impact human health and safety as well as local economies.
The UN General Assembly Resolution on Sustainable Mountain Development recognized the seriousness of threats from changing mountain ecosystems, warning they could have severe effects. The resolution states, “despite the progress that has been made in promoting sustainable development of mountain regions and conservation of mountain ecosystems, including their biodiversity, the prevalence of poverty, food insecurity, social exclusion, environmental degradation and exposure to the risk of disasters is still high.” In fact, according to the Food and Agriculture Organization of the UN, the population of people living in mountain regions increased between 2000 and 2012 and the number of people in mountain communities in developing countries vulnerable to food insecurity jumped by 30%.
The High Mountain Summit was organized to increase dialogue, connect decision makers, local stakeholders, draw links between policy and science, and create a science-based action plan for addressing changes to high mountain ecosystems. According to the High Mountain Summit website, the main concerns dealt with at the summit included environmental changes in high mountain cryosphere, effects of these changes on both ecosystems and communities downstream, and water resource availability.
The High Mountain Summit came on the heels of the publication of the most recent IPCC report. In September, the IPCC released the “Special Report on the Ocean and Cryosphere in a Changing Climate”, which included an entire chapter devoted specifically to high mountain regions. The issue of global temperature changes and their impacts on high mountain ecosystems appears to be a growing concern for both governmental organizations and individual communities. A GlacierHub article published last month addressed effects of the melting Chiatibo Glacier on the nearby village of Bumburet in Pakistan. Situated in the Hindu Kush mountain range, Bumburet has experienced devastating flooding and landslides, threatening the community’s way of life.
Visibility of issues related to changing mountain environments will likely increase as concerns continue to grow. The next conference to look out for will be the UN Climate Change Conference, which is being held at IFEMA-Feria de Madrid in Madrid, Spain from the 2nd to the 13th of December, 2019.
Historical photographs of Glacier National Park provide a glimpse into the past. The national park in Montana hasdigitized photos from the 1940s through the 1960s, which are available through the MontanaMemory Project. Funding from the federal Library Services and Technology Act and support from Glacier National Park Conservancy made the project possible. The old photographs were originally commissioned by the publicity department of the Great Northern Railway and were used as promotional pieces, encouraging tourism to the park. The railway promoted legislation that led to the establishment of Glacier National Park and the president of the company invested in local hotels, boats, roads, and chalets. The railway developed the slogan “See America First” to promote tourism to the park.
The digitized photographs reveal what tourism was like in the mid-20th century. The photos show tourists experiencing the glaciers, mountains and lakes within the park through a range of activities. They depict the Many Glacier Hotel, Glacier Park Lodge, scenic tours, boating activities on picturesque lakes, and horseback riding through the mountainous landscape.
Today, Glacier National Park is still a popular tourist attraction, but its landscape has changed drastically in the decades since the photographs were taken. According to the Glacier National Park website, when the park was first established in 1910 it was home to more than 100 glaciers. There were still 35 named and active glaciers within the park as of 1966. However, by 2015 there were only 26 named glaciers remaining. Glaciers within the park are melting, with some having lost as much as 85% of surface area. The recently digitized photos are a wonderful throwback. Additionally, they provide evidence of a landscape marked by climate change. Visit Glacier National Park’s official website to learn more about its melting glaciers and to view side by side photographs of glaciers in the early 1900’s and today.
Al Gore’s An Inconvenient Truth, captured the world’s attention and made melting glaciers and skinny polar bears the poster child for climate change. On nearly the opposite side of the globe, one of New Zealand’s national treasures has exhibited signs of global climate change for decades but has remained a relatively unknown issue.
The study, “Implications of a changing alpine environment for geotourism: A case study from Aoraki/Mount Cook, New Zealand,” published in June in the Journal of Outdoor Recreation and Tourism, details the effects of melting glaciers on the landscape of Aoraki/Mount Cook National Park and examines how this impacts geotourism and visitor experience within the park.
Tourism accounts for a fair share of New Zealand’s economy. According to Dr. Susanne Becken, Investment Advisor at New Zealand’s Department of Conservation, tourism makes up 4-5% of the nation’s GDP, and an even greater percentage of its employment. Tourists travel to New Zealand to immerse themselves in nature, and geotourism and ecotourism are popular draws.
Unfortunately for those who rely on tourism, Dr. Becken believes the industry has seen its heyday. Climate change threatens New Zealand’s natural environment, affecting Kiwis and tourists alike. Aoraki/Mount Cook National Park contains some of the largest glaciers and highest mountain peaks in New Zealand and is a destination for local and international hikers, climbers, skiers and more. However, these glaciers are shrinking rapidly.
Thinning and receding glaciers have made hiking more dangerous within the park. Guided hikes of the Tasman Glacier were a popular tourist attraction in the 1900s, but thinning ice temporarily halted tours as early as the 1950’s. In the last 40-50 years, glacier recession in Aoraki/Mount Cook has also led to the development of proglacial lakes. These lakes result from receding glaciers, as their meltwater fills the landforms left by the glaciers. Today, boat tours on the proglacial lakes have emerged as a new sight-seeing opportunity. Thus, glacier retreat has presented a mixed-bag, resulting in increased dangers for hikers and skiers, but also providing alternative tourist opportunities.
Another response to glacier retreat in Aoraki/Mount Cook has been the increased use of airplanes and helicopters to access glaciers and mountains in the park. Helicopters and planes with retractable skis have allowed glacier tours to continue and are a safer way for hikers, climbers, and hunters to access the mountains. Although it may seem like a drop in the bucket in terms of emissions, increased aircraft usage within the park does not correlate with environmentally conscious practices. In terms of visitor experience, increased aircraft usage was found to be unpopular with other visitors to the park. The study determined that 26% of visitors who walked or hiked in the park were displeased by the aircraft activity above.
In addition to the challenges presented by receding glaciers, Dr. Heather Purdie, senior lecturer at the University of Canterbury, and lead author of this study, says increased number of visitors to the park stretches resources and infrastructure thin, making sustainability an even greater challenge. Dr. Becken confirmed that just this year, the park reached a record number of tourists at 1,000,000 visitors. For this reason, balancing environmental sustainability and visitor numbers is an increasingly difficult but essential task. As Dr. Purdie said, “People come from all around the world to enjoy our beautiful landscape. If we go down the path of overcrowding as seen in many other iconic tourist destinations, then not only will our environment suffer but we will lose the fundamental attraction.”
Researchers used a mixed-methods approach of visitor surveys and interviews with relevant sources to determine the results of the study. According to Dr. Purdie, the results of the study helped researchers “understand how observed changes in the physical world is actually experienced by people.” Unfortunately, the results determined that most visitors were largely unaffected by glacier retreat. Of those surveyed, 56% of visitors were satisfied with their experience in the park.
Visitor experience may in part be owed to Aoraki mountain, which is the main draw for tourists. Key sources interviewed in Dr. Purdie’s study also acknowledged that most visitors are visiting the park for the first time and may not recognize the significance of glacier retreat. The sources interviewed for the study were composed of park managers, scientists, tour operators, and professional and recreational alpinists. The mountains and glaciers within Aoraki/Mount Cook have sentimental value for many interviewees. Those interviewed provided crucial insight as they continually visited the park and watched the landscape change over time. These key sources expressed fear of further physical changes to the park from both environmental and economic perspectives. One interviewee remembered visiting the park decades before bringing their children and noted how drastically the park had changed between visits.
Climate change has left its mark on Aoraki/Mount Cook National Park, visible in the receding glaciers and growing proglacial lakes. Researchers involved in the study are hopeful that geotourism can promote sustainability among visitors to New Zealand and lead discussions of climate-related issues. Dr. Purdie emphasized this, saying, “Quality geotourism can be an important tool to teach people about our wonderful environment.” She stressed that “trying to find a balance between tourism and environmental sustainability,” must be a priority moving forward. In the meantime, she and fellow researchers are “keen to highlight the issue to hopefully stimulate some thinking around this issue.” Dr. Purdie and her fellow authors have conducted research in Aoraki/Mount Cook National Park for years. They have watched the changes to the mountains and glaciers in the park unfold and plan to continue to monitor glacier and environmental changes within the park.
The Duke and Duchess of Cambridge traveled earlier this month to a remote Pakistani village, Bumburet, in the Hindu Kush to view the Chiatibo Glacier. The royal visit is notable because it is the first time the couple has seen a melting glacier.
In a two and a half minute video published by Sky News, the couple discusses climate change and interacts with members of a nearby community.
As a result of rising temperatures in the region, Chiatibo is retreating at a rate of 10 meters each year. Melting glaciers in the Hindu Kush and Himalayas threaten drinking water supplies for 1.6 billion people. Bumburet was hit in 2015 by intense flooding and a landslide, which destroyed homes, a police station, and agricultural lands.
The most recent report from the Intergovernmental Panel on Climate Change, published Sept. 25, describes the dire state of the world’s oceans and cryosphere and the projected consequences of human-caused climate change. In addition to describing the risk of long-term depletion of water resources, such as at Chiatibo, the report also highlights the risk of flooding and landslides brought about by glacial melt.
The Kalash people of Bumberet have a rich history and culture that pre-dates both Islam and Christianity. But the 2015 flooding left them with lingering anxiety, Sky reports. Some villagers have proposed moving to higher elevations in order to escape the dangers brought about glacier melt, highlighting the extent to which climate change is threatening societies that have endured harsh climates for centuries.