State of the Cryosphere Report 2024: Mountain Glaciers and Snow

In the State of the Cryosphere 2024 – Lost Ice, Global Damage report, over 50 leading cryosphere scientists warn of vastly higher impacts and costs to the global economy given accelerating losses in the world’s snow and ice regions. The report was released in November 2024 at the 29th Conference of the Parties (COP29), hosted in Baku, Azerbaijan.

Current climate commitments, leading the world to well over 2°C of warming, would bring disastrous and irreversible consequences for billions of people from global ice loss. Based on the most recent cryosphere science updates from 2024, the authors underscore that the costs of loss and damage will be even more extreme, with many regions experiencing sea-level rise or water resource loss well beyond adaptation limits in this century if our current level of emissions continues – leading towards a rise of 3°C or more. Mitigation will also become more costly due to feedbacks from thawing permafrost emissions and loss of sea ice.

A specific chapter of the report is dedicated to Mountain Glaciers and Snow. One of its lead scientific reviewers is former UIAA Mountain Protection Commission President Carolina Adler (2016-2024). Dr Adler is an Environmental Scientist and Geographer with an international career spanning over 25 years in both research and practice in the public and private sectors. Among her many roles, she is also a Lead Author for the Intergovernmental Panel on Climate Change (IPCC), specifically in the chapter on High Mountain Areas of the Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), adopted in September 2019, as well as the Working Group II contribution on Impacts, Vulnerability, and Adaptation and Co-Lead for the Cross-Chapter Paper on Mountains, adopted by the Panel in February 2022.

The chapter identifies the critical role of glaciers and snowpack on water resources and the impacts of climate change on their availability. Glaciers provide essential water for drinking, irrigation and hydropower, particularly in high mountain areas. Rapid glacial melting has led to a ‘peak’ in water availability, followed by declines as many glaciers continue to shrink. This, in turn, has created instability, threatening water supplies, ecosystems, and economies, particularly in vulnerable regions.

As the research charts, worst-case high-emission scenarios could lead to near-total losses of glaciers outside polar regions by 2100, exacerbating risks like flooding, droughts, and irreversible ecosystem disruption. The authors call for immediate emission reductions and adaptation efforts to preserve the remaining glaciers and snowpack. As detailed in the takeaways below, achieving the Paris Agreement’s 1.5°C target is critical to mitigate losses and maintain vital ecosystem services.

The chapter presents the following key takeaways:

Current Nationally Determined Contributions (NDCs) (2.3°C by 2100): Even 2°C will lead to escalating loss and damage throughout this entire century, well beyond limits of adaptation for many mountain and downstream communities. Nearly all tropical and mid-latitude glaciers would cross thresholds causing their eventual complete loss, with critically important High Mountain Asian glaciers losing around 50% of their ice. Catastrophic hazard events seen already today, such as glacial lake outburst floods and landslides, will increase in frequency and scale. Risks are especially high in Asia, where outburst floods can wash away infrastructure and cities within hours with little warning. Severe and potentially permanent changes to the water cycle, due to loss of snowpack and ice run-off during the warm summer growing season, will impact food, energy and water security.

1.5°C Consistent Pathways: This level of mitigation is the only chance to preserve at least some minimum glacier ice (15–35%) in some mid-latitude regions, including Scandinavia, the Alps, and Iceland; and maintaining up to 50% of current ice in the Caucasus, New Zealand and much of the Andes. Losses in High Mountain Asia will be far less at this temperature level, with two-thirds preserved glacier ice. Nearby communities must nevertheless prepare for significant adaptation efforts in coming decades, including continued catastrophic floods, especially with extreme rain-on-snow events. However, for most communities, these changes will not move beyond adaptation limits, and rates of glacier melt would slow by mid-century, and stabilize by 2100. Snowpack would also stabilize, though at higher altitudes than today. Some glaciers might even begin to show signs of very slow re-growth in the 2200s, as one of the first possible visible signs of planetary restoration in net-zero pathways.

Current rise in CO₂ levels continues (3–3.5°C by 2100): Catastrophic and cascading impacts from glacier and snow loss are associated with such levels of rapid warming, with some vulnerable mountain and downstream communities experiencing non-survivable conditions already by mid-century due to loss of seasonal water availability, or destructive floods from which they are unable to recover. Over time, even many of the largest glaciers in High Mountain Asia and Alaska are unlikely to survive. Snowpack will become unreliable, with rain falling at higher elevations and more frequently throughout the year when snow would otherwise be expected. Currently fertile agricultural regions such as the Tarim and Colorado River basins may no longer be able to support significant agricultural activities. Losses in mountain biodiversity stemming from cryosphere warming will be extreme across many high-elevation ecosystems.

Furthermore the document presents the following updates specific to the picture of glaciers across the world in 2024:

2024 Updates

• Glacial melt globally set a record loss in 2023, according to the World Glacier Monitoring Service (WGMS).Reported observations thus far from 2024 indicated record losses in some regions, with Sweden showing the highest melt levels in 80 years of observations. Currently, 2024 is also on a record loss trajectory in Asia. Extremely low snowfall combined with extremely high summer temperatures seem to have contributed to high 2024 loss in these regions.
• Venezuela joined Slovenia as the second country in the world to lose its final glacier: the Humboldt Glacier ice field became too small to flow under its own pressure in spring 2024, thus becoming stagnant at approximately 0.01 km.
• Glaciers in the Andean tropics are now smaller than at any time in 11,700+ years. In 2024, they became the first global glacier region confirmed to be smaller than at any previous time since the end of the last Ice Age.
• 2024 data from 5,500 glaciers across the Andes show the mountains have lost 25% of their ice coverage since the Little Ice Age, and that their tropical glaciers are melting ten times faster than the cumulative global average.
• The melt rate of the Juneau Ice Field quintupled between 2010–2020 compared with the 1980s, potentially locking in continued ice loss and centuries of consequential sea level rise.
• Ten million people are currently at risk of catastrophic flooding hazard events from glacial lake outburst floods, especially in Alaska, High Mountain Asia, and Iceland. In Asia alone, the frequency of these events is expected to triple by century’s end without substantial emission reductions.
• Under a high emissions scenario, two-thirds of Mount Everest’s famous East Rongbuk Glacier is projected to be lost by 2100. In addition to being an iconic part of the Asian water tower, East Rongbuk has climbing and cultural significance.
• New observations from glacial meltwater in Svalbard, Greenland, Iceland, and Alaska show high levels of methane, in part from permafrost. This confirms that mountain glaciers are a methane source and underscores the importance of including permafrost thaw in NDCs.
• Northern hemisphere winter 2023–2024 saw record low snowfall in the Hindu Kush Himalaya, highlighting concerns for runoff-fed rivers and water security.
• Locked-in melt has committed the loss of at least one-third of glacier mass in the European Alps glaciers by 2050 without further warming. With the current warming trajectory, two-thirds of the glacier mass may be lost by 2050. In western Austria, near-complete glacial loss is projected if the lower 1.5°C Paris limit is not achieved.
• Recent findings on ice retreat in the Eastern Himalaya show climate change directly links to glacier instability that drives cascading hazards.
• A paper from July 2024 finds fluctuations in Peruvian Andes meltwater that are directly linked with changes in global biodiversity. This suggests mountainous aquatic biodiversity will be affected globally as glaciers retreat.

Download the full State of the Cryosphere Report 2024

This article forms the part of a series produced by the UIAA for International Mountain Day 2024.

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