Climate Change Threats to Third Pole Glaciers | BBC News

The video explains the concept of glacial lake outburst floods (GLOFs). The instructor describes how glacial lakes form when glaciers melt and water accumulates in depressions on mountains. The instructor explains that these lakes can become dangerous when the dam holding the water breaks, releasing massive amounts of water suddenly. The instructor uses the example of Chamoli in Uttarakhand, where a glacial lake outburst caused a devastating flood. The instructor explains that GLOFs are rapid events that can cause destruction within hours, making early warning systems crucial for disaster management.

Glacial lakes form when glaciers melt and create depressions that fill with water. These lakes can be extremely dangerous because if a glacier dam breaks or a large ice chunk falls into the lake, it can trigger a massive flood (GLOF). In Peru, communities live with an 'sword of Damocles' above their heads, constantly monitoring these lakes. The risk increases as glaciers retreat and leave behind unstable slopes.

Glacial lake outburst floods occur when glacial ice collapses, releasing massive amounts of water and debris. In the Swiss village of Betten, a 2-kilometer glacier collapsed in late May, causing mud and rock avalanches that blocked the Lonza River. This prevented water from flowing normally and made rescue operations extremely difficult. Such events are rare and unprecedented in recorded history, with 3 million cubic meters of ice collapsing at once.

Glacial Lake Outburst Floods (GLOFs) are catastrophic natural disasters that occur in Himalayan regions. These floods happen when glacial lakes, formed by melting glaciers between mountains, suddenly burst due to heavy rainfall or cloud bursts. The water from these lakes rushes down mountain valleys, causing flash floods that destroy everything in their path. The 2013 Uttarakhand tragedy is a notable example. GLOFs are triggered by global warming, which causes glaciers to melt faster, and can also be triggered by earthquakes. The NDRF (National Disaster Response Force) has taken control of such situations and help lines have been established for affected populations.

Glacial lake outburst floods (GLOFs) are catastrophic natural disasters that occur when a glacial lake bursts its natural dam, releasing massive amounts of water that can destroy infrastructure and cause widespread devastation. In this incident, a glacier in Uttarakhand, India, broke apart and damaged the Rishiganga dam, triggering a flood that killed an estimated 100-150 people and destroyed critical infrastructure including a military bridge.

Satellite remote sensing technologies, including optical imagery, synthetic aperture radar (SAR), interferometric radar, and altimetry, enable scientists to measure and monitor Earth's cryosphere (ice-covered regions) with unprecedented precision, revealing critical information about ice sheet dynamics, sea ice changes, and mass balance that helps us understand climate change impacts on polar regions.

The CryoSat mission demonstrates how satellite-based radar altimetry can monitor changes in Earth's cryosphere (ice and snow) by measuring elevation changes with centimeter precision from orbit, enabling scientists to track ice loss from glaciers, ice sheets, and sea ice that contributes to rising sea levels and climate change impacts.

Glacial mass balance estimation uses geodetic methods including photogrammetry, altimetry, and Digital Elevation Model (DEM) differencing. Stereo pairs are two satellite images of the same area taken from different angles or times, processed using computer vision algorithms to generate Digital Elevation Models. The difference between DEMs from different time periods reveals elevation changes, which combined with ice density calculations provide quantitative measures of glacial mass loss.

The cryosphere—the ice mass of our planet including ice sheets, permafrost, and polar ice—acts as a moderator of ocean and atmospheric temperatures and serves as a sun reflector. Climate change is shrinking ice caps in a runaway effect, with 99% of Earth's fresh water stored in ice sheets. Operation IceBridge, NASA's longest-running Airborne Science Program, monitors changing ice sheets, glaciers, and sea ice. The world is warming faster in the Arctic than anywhere else by a factor of 2.5 times the global average. Ice caps are melting because of greenhouse gases—carbon dioxide, methane, nitrous oxide, and fluorinated gases—that heat the atmosphere by trapping energy. In the post-industrial age, CO2 rises precede temperature rise, indicating a fundamentally different process from pre-industrial times. Generating long-term data sets is essential for studying climate, with new generations of Earth observation satellites coming online. ESA has deployed Aeolus, MetOp-3, and Sentinel-3, while NASA has launched ICESat-2 and GRACE-FO. All share radar altimeters measuring sea and ice cap heights. The US-Europe cooperation agreement from 1998 ensures shared instruments between European and American satellites.

The Himalayan cryosphere (glaciers and seasonal snow) is critically important because it provides water to major Indian river systems including the Indus, Ganga, and Brahmaputra. These rivers originate from Himalayan glaciers and seasonal snow fields, making north Indian rivers perennial rather than seasonal. Understanding this cryosphere is essential for water resource management that has sustained Indian civilization for centuries. Scientists developed a glacier inventory program starting with field expeditions to glaciers like Chotash Greek. By combining satellite image interpretation with field observations (identifying stream origins as clues to terminus locations), researchers created the first glacial inventory atlas of Indian Himalaya in 1991, revealing approximately 25,000 square kilometers of glacier area. The entire Himalayan range spans 4 million square kilometers with 60,000 square kilometers covered by glaciers. Glacier count is unreliable because glaciers are dynamic—tributary glaciers separating from main trunks become independent, changing counts without actual loss. Remote sensing using satellite technology is essential for studying the Himalayan cryosphere because glaciers and snow are located in very remote locations that are difficult to access for ground-based study. The Normalized Difference Snow Index (NDSI) was developed to automatically monitor seasonal snow cover across large Himalayan areas using two spectral bands: visible light (reflected by snow) and near-infrared (absorbed by snow). Field investigations determined appropriate threshold values (around 0.4) for identifying snow cover. Glacial mass balance is the difference between accumulation (snowfall and ice formation) and ablation (melting of snow and ice) on a glacier over a given period. It is critically important because it is highly sensitive to climate changes in precipitation and temperature, determines eventual glacier retreat, and indicates water release for hydrological planning. Traditional methods required extensive field teams and could only monitor a few glaciers, leading to incomplete understanding. The Accumulation Area Ratio (AAR) technique was developed to estimate mass balance using satellite imagery by monitoring snow line retreat during summer. The ratio of glacier area above the equilibrium line to total area is calculated and related to mass balance. This technique allows mass balance estimation for thousands of glaciers, revealing that mass loss varies throughout the Himalayas rather than being uniform.

Effective planned relocation requires people-centered approaches involving affected communities in decision-making and building on local knowledge systems. Most relocation efforts fail when displaced populations don't understand why they must move and host communities aren't adequately engaged. Clear national frameworks designed with community inputs are essential for safeguarding rights, emphasizing proactive planning, long-term commitment, and sustainable financing since relocation is a prolonged process. The Sahel Spatial Development Strategy demonstrates territorial spatial planning methodologies strengthening settlement networks hosting displaced populations and building urban-rural linkages. The Urban Planning and Infrastructure in Migration Context project employs a four-part approach: spatial analytics, visioning and scenario building, participatory design for infrastructure prioritization, and linking proposals to financiers. For dryland regions facing escalating climate impacts, nature-based solutions offer effective adaptation strategies including floodable amphitheaters, sand dam orchards, and water spreading bunds. The MENA region faces interconnected climate and conflict displacement challenges, being one of the world's most water-stressed regions and a climate change hotspot where some nations have already exceeded 1.5°C warming thresholds. Approximately 233,000 disaster displacements have been linked to climate in the region, with projections indicating 19 million internal climate migrants by 2050. Jordan exemplifies the dual challenge of hosting approximately one-third refugee population while being one of the world's most water-scarce countries, having launched the Climate Refugee Nexus Initiative at COP27 to address these compounded challenges.

The socio-economic aspects of the Mountain region include: (1) Population - 6.73% according to 2011 census; (2) Districts - 16 districts; (3) Caste and ethnic groups - various ethnic communities; (4) Religious sites - important religious places; (5) Houses - flat-roofed houses with small windows; (6) Major occupations - animal husbandry and tourism; (7) Lifestyle - people temporarily migrate to Hill and Terai regions in winter along with their cattle and return in summer.

Disaster displacement differs fundamentally from refugee situations under international law. The media frequently uses 'climate refugees,' but this term is legally problematic because refugees are defined as people fleeing political persecution, not environmental hazards. The Nansen Initiative Protection Agenda established that disasters result from interactions between hazardous events and human conditions of exposure, vulnerability, and capacity. People are displaced when forced to leave homes due to disasters through spontaneous flight, enforced evacuation, or planned relocation—characterized by lack of real choice. Displacement is always multi-causal, involving environmental hazards, population density, poverty, lack of resilience, and sometimes weak governance. Addressing climate-induced displacement requires a comprehensive three-pillar strategy: reducing hazard through Paris Agreement implementation; reducing exposure through planned relocation and regular migration channels; and reducing vulnerability through adaptation and resilience building. Planned relocation should be a last resort requiring legal frameworks, community consultation, and livelihood preservation. Durable solutions include return, local integration, or relocation. Voluntary migration pathways can be facilitated through existing free movement agreements. The Caribbean Migration Consultations process is developing regional frameworks for managing climate-induced mobility, recognizing that effective response requires helping people stay, move safely, and be protected once displaced.

Communities facing climate change need support to adapt, which may involve voluntary migration before forced displacement occurs. Three out of four displaced persons globally originate from countries already highly fragile in terms of climate vulnerability. Supporting adaptation helps communities achieve their desired futures, whether that involves staying in place through improved resilience or migrating proactively to safer locations.

This extensive panel discussion presents a comprehensive analysis of climate-induced displacement through four expert presentations followed by detailed Q&A. The Internal Displacement Monitoring Centre reveals that disaster displacement is concentrated in Asia, particularly South Asia, reflecting high hazard exposure and vulnerability. Three persistent myths require correction: displacement is not necessarily short-term, protracted displacement typically remains within affected countries, and disasters result from human vulnerability rather than being purely natural events. Research in Bangladesh demonstrates that vulnerability varies significantly by gender and socioeconomic status, with women facing different challenges than men in both origin and destination areas. Migration is a complex multi-causal phenomenon where climate change exacerbates existing vulnerabilities rather than directly causing displacement. Non-migration represents a valid adaptation strategy, with less than 4% of international migrants globally choosing to stay despite disaster risks. Current policies often concentrate adaptation programs at local levels without addressing urban destinations, requiring decentralized approaches and recognition of voluntary non-migration as legitimate adaptation.