Breaking the Ice: Glacial Lake Outburst Floods impact of climate change
By Ms. Prasuna Khatri*
Among the many global environmental issues, glacial lake outburst (GLOFs) are one of the most serious and threatening impacts of climate change especially in the Himalayas and Andes region. Since 1990 the number of glacial lakes has been increasing rapidly. Globally, more than 15 million people are exposed to impacts from potential GLOFs. Populations in High Mountains Asia (HMA) are the most exposed and on average live closest to glacial lakes with ~1 million people living within 10 km of a glacial lake. The number of glacial lakes are increasing due to melting of ice which is driven by humans’ activities like fossil fuel combustion, industrial process and deforestation.
What Causes a Glacial Lake Outburst Flood (GLOF)?
A glacial lake outburst flood (GLOF) happens when water stored in a glacial lake suddenly bursts out due to the failure of a natural ice dam. GLOFs often result in catastrophic flooding downstream with major geomorphic and socioeconomic impacts.According to ICIMOD these lakes are impounded by moraine complexes, glacial ice or even bedrock. Due to events like breaches, slope collapses, overtopping, or other types of structural failure, glacial lakes in high mountain regions can trigger devastating disasters that put lives, livelihoods, and essential infrastructure at serious risk.
Nowadays it is seen more because the glaciers are melting faster due to climate change. These events are now seen more frequently because glaciers are melting faster due to climate changes. As global temperature rises, the amount of glaciers decreases leading to formation of large volumes of meltwater in glacial lakes. When the natural dams fail, this large volume of water is suddenly released,which affects downstream living communities. GLOFs are not just environmental events; they raise complex legal issues involving international responsibility, climate justice, and transboundary harm.
International Legal Frameworks and State’s Responsibility in Addressing GLOFs
This blog explains that disasters like GLOFs are not just about melting ice or changing landscapes; they also raise legal and human rights questions. As climate change accelerates, new legal interpretation from international courts can help countries work together, develop better environmental laws and empower young people from vulnerable regions to demand meaningful action.
In the Hindu Kush Himalaya region, it’ is common to find glacial lakes held back by natural walls of rock and debris, called moraines. Glacier lakes emerge as glaciers retreat, leaving depressions in the landscape that fill with meltwater. As global temperatures rise due to anthropogenic greenhouse gas emissions, the size and number of these lakes are growing rapidly. Many of these lakes are contained by natural dams made of ice or loose debris, which are often unstable. As time passes and the lakes expand, they pose increasing risks to communities living downstream. When the moraine or ice dam holding a glacial lake fails due to seismic activity, heavy rainfall, or internal pressure, it results in a glacier lake outburst flood (GLOF), which can wipe out the entire settlement.
South Asian countries like Nepal, Bhutan, and northern India are especially vulnerable, with dozens of potentially dangerous glacial lakes identified. Similarly, in the Andes, Peru and Bolivia face similar threats. In East Africa, the Rwenzori Mountains are beginning to show early warning signs of similar dynamics. According to the report by ICIMOD Nepal has experienced at least 24 GLOF events in the past. Out of these, 14 are believed to have occurred in Nepal itself and 10 were the result of flood surge overspills across the China (Tibet AR)-Nepal border.
On August 16, 2024 the village of Thame in Nepal’s Solukhumbu region was destroyed by a destructive flood caused due to an outburst flood from Thyanbo glacial lake.This disaster destroyed homes, hotels, school, and health posts, shaking a sherpa community who are known for its rich sherpa heritage. This tragic event shows how the risks posed by glacial lakes are increasing as climate change accelerates.
In 2025, not just one but two glacial origin floods strike Nepal: in Rasuwa, and in Upper Mustang. The increase of anthropogenic greenhouse effect increases the melting of ice and forms glacial lakes. Due to failure to hold the water it caused the glacial lake outburst. China -Nepal flood is caused by the draining ‘supraglacial’ lake that started to form as a small pond which grew significantly later. According to Dr. Nitesh Khadka, a scientist at the Chinese Academy of Sciences, the flood in Rasuwa was caused by water leaking from a supraglacial lake covered by snow and debris. Due to the outburst glacial lakes in Rasuwa it caused a flood which swept away the bridge's cross-border link between Nepal and China leaving damage to the people living downstream.
Climate disasters like Glacial Lake Outburst Floods (GLOFs) are no longer seen just as environmental or humanitarian problems; they are now also being recognized as legal issues. These disasters raise important questions about what countries are required to do under international law. Although the recent initiative for an advisory opinion from the International Court of Justice (ICJ) which is led by Vanuatu and supported by several climate-vulnerable nations. This advisory opinion has centered on the issue of sea-level rise which is the fundamental legal principle. It seeks to clarify such as state responsibility and the duty to prevent environmental harm which are equally relevant to other climate-related threats, including Glacial Lake Outburst Floods (GLOFs).
These include the no-harm rule, the duty of due diligence, and state obligations to protect human rights in the face of climate change. Vanuatu and the Melanesian Spearhead Group (MSG) emphasized that under international law, states have obligations to act due diligence, prevent substantial environmental damage, safeguard human rights, and ensure the protection and preservation of the marine environment.
The no-harm principle recognized in landmark cases like the Trail Smelter Arbitration and enshrined in Principle 21 of the Stockholm Declaration establishes that states have a duty to prevent activities within their borders from causing significant environmental harm to other countries. When emissions from major polluting nations accelerate glacial melting and the formation of unstable glacial lakes in sensitive regions like the Himalayas, it results in Glacial Lake Outburst Floods (GLOFs) which can have devastating cross-border impacts. In such cases, affected states may invoke this principle to argue that high-emitting countries bear state responsibility under international law for contributing to climate-related harm beyond their borders. Trail Smelter Arbitration (1941), which is the case between the US and Canada, established the "no harm" principle holding states responsible for transboundary environmental damage. This principle is now central to climate accountability claims.
In 2023, the United Nations General Assembly asked the International Court of Justice (ICJ) to give its advisory opinion that seeks to clarify the obligations of states under international environmental law and international human rights law in relation to the climate crisis. Although the main concern was sea-level rise, the opinion is expected to elaborate on broader obligations to mitigate and adapt to climate impacts. These ideas can also apply to disasters like Glacial Lake Outburst Floods (GLOFs). For example, in the Teitiota v. New Zealand case the UN Human Rights Committee said that if a government fails to take action to prevent serious climate-related harm, it could be seen as a violation of people’s right to life under Article 6 of the International Covenant on Civil and Political Rights (ICCPR).
GLOFs should not just be seen as natural disasters, they are made worse by human-driven climate change and carry serious legal and moral weight. It is not just about responding after a flood hits. We need stronger accountability, cross-border cooperation, and real climate justice. This is especially urgent for countries like Nepal, Bhutan, and Peru, where entire communities are already living under the threat of these deadly floods.
The Role of International Courts in Tackling Climate Risk
Glacial Lake Outburst Floods (GLOFs) are increasingly recognized as a serious consequence of climate change with legal implications for both states and major emitters. GLOFs are closely linked to anthropogenic greenhouse gas emissions, raising complex questions about liability, state obligations, and access to justice for affected communities. Advisory opinions issued by international institutions such as the International Court of Justice (ICJ), the Inter-American Court of Human Rights (IACtHR), and the International Tribunal for the Law of the Sea (ITLOS) are increasingly helping to define and interpret states' legal responsibilities concerning climate change. Although these opinions do not specifically focus on Glacial Lake Outburst Floods (GLOFs), they establish fundamental principles such as the obligation to prevent transboundary environmental harm and safeguard at-risk communities which can serve as a foundation for future legal interpretations related to GLOFs and other climate-driven hazards.
These disasters are not only predictable because of climate change they are also becoming more frequent. Often, their impacts cross national borders, affecting countries that have contributed little or nothing to global warming.Upstream states are not always high-emitting nations, although they often are in climate-related discussions. The term “upstream state” typically refers to a country located upstream of a transboundary river or glacial system, in the context of Glacial Lake Outburst Floods (GLOFs), it can also refer to the country where the glacial lake is physically located like Nepal or Bhutan in the Himalayas. In the case of GLOFs, the upstream state is the one where the lake might burst, causing floods that could affect countries downstream.
On the other hand, high-emitting nations are those responsible for a large share of global greenhouse gas emissions like the United States, China. These countries might be located far from the Himalayas, but their emissions still contribute to global warming and the melting of glaciers thousands of miles away. So, while an upstream state might be vulnerable to disasters like GLOFs, it is not necessarily a major polluter. And high-emitting countries might not directly face GLOFs but can still be held accountable under international law for contributing to the conditions that cause them.
International courts and tribunals are clarifying the obligations of states regarding climate change and related disasters:
International court of justice (ICJ): In the Pulp Mills on the River Uruguay case (Argentina v. Uruguay), the International Court of Justice was established that nations have a duty to conduct environmental impact assessments if their activities might harm other countries. This principle is highly relevant to the future cases involving Glacial Lake outburst flood (GLOFs), where infrastructure projects may increase the risk or where emission from upstream developments contribute to accelerated glacial melting.
International Tribunal for the Law of the Sea (ITLOS)-Although it mainly deals with ocean- related issues but ITLOS delivered advisory opinion issued in Case No. 31 (2022–2024), requested by the Commission of Small Island States on Climate Change and International Law (COSIS). It states the obligations of states on climate change and international law.
It holds that all states must exercise due diligence and have a duty of care to prevent serious harm caused by rising sea level and other climate impacts. While the advisory opinion directly concerns the marine environment, its legal principles especially regarding transboundary harm and state responsibility are also relevant to inland climate hazards such as Glacial Lake Outburst Floods (GLOFs). GLOFs often affect transboundary rivers and downstream communities, making this opinion applicable to state duties beyond the ocean. The advisory opinion stressed the need for countries to collaborate and align their policies to manage climate risks effectively.
Inter-American Court of Human Rights (IACtHR)- The IACtHR recognizes a healthy environment as a fundamental human right in its Advisory Opinion OC-23/17, issued on November 15, 2017. The court emphasized how environmental harm and climate change directly impact fundamental human rights. The Advisory Opinion OC-23/17 issued by IACtHR laid out three main responsibilities for states: to prevent environmental damage (including like conducting impact assessments and preparing for emergencies), to cooperate with neighboring countries in good faith when environmental issues cross borders, and to guarantee access to information, justice, and public participation. This landmark advisory opinion was requested by Colombia and is considered a milestone in environmental human rights law.
The advisory opinion OC‑32/25 confirms that the duty to prevent irreversible damage to the environment and climate has become a jus cogens norm, a fundamental, peremptory principle of international law that is non-derogable, non-negotiable and is universally binding on all States. The Inter-American Court of Human Rights’ Advisory Opinion OC-32/25 is a landmark interpretation that addresses the intertwined challenges of the climate emergency and human rights obligations of states within the Americas. The advisory opinion sets a historic precedent that strengthens States’ legal obligations to prevent climate-related harm and guarantee rights including the right to a healthy environment and climate, access to environmental information, effective participation and consultation, access to justice, the right to defend rights, enhanced protection for vulnerable groups, and recognition of common but differentiated responsibilities among countries. The Court declared that the climate crisis is an urgent threat and requires immediate, rights-based action for sustainable development and human dignity.
GLOFs have displaced communities, destroyed infrastructure, and claimed lives, highlighting the intersection between climate change, disaster risk, and human rights. The advisory opinion OC-32/25 gives affected communities legal grounds to demand state action such as risk reduction, reparations, and adaptation support aligning disaster risk reduction with international human rights law obligations. This especially relevant to the glacier lake outburst which disproportionately affect marginalized and indigenous mountain communities who have lack of infrastructure and resources to protect themselves from the effect. If governments are aware of these risks and fail to act, their inaction may itself violate human rights. Protecting the environment is not only about ecosystems but it is about justice, human dignity, and survival.
Accountability and Climate Litigation: From Global Polluters to Local Victims
The case of Saúl Luciano Lliuya v. RWE AG (initiated in 2015 in a German civil court) is a landmark in climate litigation, where a Peruvian farmer sought partial responsibility from a major German energy company for contributing to the melting of Andean glaciers above his hometown of Huaraz. This case highlights the increasing global risk of the GLOFs due to climate change. It demonstrates both the potential and the challenges of using legal systems to hold major polluters accountable for climate impacts.
Although Lliuya did not receive compensation, the case marked a significant step in climate litigation by acknowledging that companies can be partially responsible for transboundary climate harms. It also emphasizes the importance of attributing responsibility for climate-induced disasters like GLOFs not only to local actors but also to global emitters whose emissions contribute to these risks. Moreover, this case underscores the urgent need for robust international cooperation, legally binding frameworks, and adequate climate finance to support vulnerable communities.
The Paris agreement is a legally binding international treaty on climate change. The Paris agreement recognizes common but differentiated responsibilities (CBDR) and provides pathways for loss and damage compensation. Article 8 of the Paris agreement provides loss and damage compensation. Countries facing climate impacts like GLOFs may now seek support under mechanisms like the Loss and Damage Fund agreed upon at COP 28 2023. The Paris agreement is built in the continuation of the Warsaw International Mechanism for Loss and Damage associated with Climate Change Impacts. GLOFs are are fast, transboundary, and deadly, they demand attention within global legal and institutional frameworks.International bodies such as the World Meteorological Organization (WMO) and the UN Environment Programme (UNEP) must establish clear legal guidelines and ensure that funding mechanisms are guided by scientific expertise and supported by enforceable decisions.
Policy and Institutional Responses to protect from GLOFs
Countries like Nepal and Pakistan are using remote sensing and hydrological modeling to map GLOFs risks and plan interventions. Pakistan is implementing a project to reduce GLOF focusing both macro and micro levels which includes:
Building stronger institutions to carry out policies and investments aimed at preventing GLOF-related damage.
Improving access to research, knowledge, and risk assessments so policymakers can make better decisions.
Setting up early warning systems and encouraging local communities to adapt and prepare, helping reduce harm to people and property.
Documenting successful strategies so they can be shared and applied in other areas.
Despite these efforts, many disaster management policies like Nepal’s National Policy for Disaster Risk Reduction (2018) which broadly addresses climate-induced disasters but lacks detailed provisions and funding mechanisms specifically for GLOFs, such as glacial lake surveillance and relocation planning for downstream communities. These are not fully equipped to address the unique challenges of GLOFs threats. International legal developments offer pathways to empower affected countries to seek support from high-emitting nations and hold them accountable for their role in global warming. The establishment of the Loss and Damage Fund at COP28 (2023) aimed at providing financial assistance to vulnerable countries suffering from climate-induced disasters like GLOFs. The Sendai Framework for Disaster Risk Reduction (2015–2030) is not legally binding, but this global framework emphasizes risk governance, early warning systems, and transboundary cooperation which are all crucial for managing the unpredictable nature of GLOFs in the Himalayas. It encourages states to integrate climate and disaster risk reduction in mountainous regions.
According to the UN Special Rapporteur on Human Rights and the Environment David R.Boyd has emphasized that climate change threatens a wide range of human rights, including the rights to life, water, food, health, housing, and culture. It emphasizes that the impact of climate change like glacier lake outburst not only affects the environment but also impacts human rights.The IPCC Sixth Assessment Report highlighted the unfair burden placed on least developed countries (LDCs) like Nepal and Bhutan nations that contribute the least to climate change but suffer the most from climate-driven disasters such as GLOFs. This raises important questions about fairness, justice and international responsibility. States are now taking serious action to protect the vulnerable populations by establishing early warning systems, building infrastructure and providing direct support to impacted countries. For example, the Government of Nepal has partnered with UNDP and ICIMOD to establish early warning systems, strengthen infrastructure, and reduce water levels in dangerous glacial lakes like Imja Tsho. Governments are working with neighboring countries through platforms such as SAARC and pushing for global mechanisms to deliver climate finance, including the UNFCCC’s Loss and Damage Fund, which also aims to support the recovery and resilience of the most vulnerable communities.
Youth and Climate Justice: Voices from the Frontlines
For many young-centered perceptivities, the threat of Glacial Lake Outburst Floods (GLOFs) is not a distant future problem, it is a present danger. A sudden flood could destroy homes, schools, and entire communities in minutes. Youth-led climate justice movements emphasize the urgent need for intergenerational equity and the protection of their future rights. Youth from countries like Nepal, Bhutan, Pakistan and other south Asian countries are speaking up and demanding for protection from the impact of climate change.
The young generation must be included in the decisions making. People want access to better information about risk and seek justice, which is often called “climate justice”. International law provides a powerful tool for amplifying youths' voices and holding states accountable. The Paris agreement preamble and article 12 recognizes the importance of public participation, including youth in addressing climate change. It includes Loss and Damage provisions (Article 8) which are relevant to GLOFs as they cause sudden, devastating loss to vulnerable communities in mountainous countries like Nepal. The Loss and Damage Fund (LDF) established at COP28 in 2023 serves as a vital mechanism that youth advocates can utilize to demand both financial support and climate justice for communities affected by disasters like Glacial Lake Outburst Floods (GLOFs), which are driven by climate change.
Advisory opinions from bodies like those by ITLOS, IACtHR, and the ICJ can set important precedents that influence national laws and policies to prioritize the needs of the most vulnerable, including young people. While these legal tools may seem slow and technical, they can set powerful precedents. The UN Human Rights Council Resolution 48/13 (2021) recognized for the first time that a clean, healthy, and sustainable environment is a human right. Youth can use this resolution to frame GLOFs as a human rights issue, where climate inaction endangers their life, security, and culture for the future. Juliana v. United States is considered one of the most prominent youth climate cases in the United States. The lawsuit was filed in 2015 by 21 young plaintiffs, all under the age of 21 at the time, who argued that the federal government’s actions exacerbating climate change violated their constitutional rights.Although Juliana did not succeed in the federal courts, it remains a landmark for youth climate advocacy and legal strategy.Similar cases can be modeled in countries like Nepal or Bhutan, where melting glaciers threaten communities. Youth can argue that failure to act on GLOF risks violates their right to life, property, and dignity.
Youth activism has been instrumental in initiating, shaping, and sustaining the worldwide campaign that led to the ICJ advisory opinion on climate change, demonstrating the power of youth-led movements like PISFCC to influence international legal processes and foster state accountability on the climate crisis.
The ICJ’s opinion expected on 23rd July 2025 would establish that failing to mitigate climate risks, including GLOFs, violates international law, such as the right to life, the right to a healthy environment, and the duty of prevention. Youth can use this advisory opinion to push for climate adaptation funding in GLOF-prone regions, Hold high-emitting states accountable for climate-driven disasters and also frame GLOFs as a legal and human rights issue, not just a natural hazard.
In Nepal, for example, young activists are pushing for better monitoring of glacial lakes and making sure climate education reaches every person. GLOFs are not natural accidents, they are worsened by the actions of major polluters. People are demanding the world to recognize this, accountability for those responsible and protection for vulnerable communities.
As a young person witnessing the change of the climate, I know it is humans who make the climate worse. We, the youth, didn't create this crisis, but we are determined to shape the response. If our voices especially of young people and Indigenous communities are heard in courtrooms, classrooms, and climate summits, then they can build a safer and more just future for all.
Conclusion
Glacial Lake Outburst Floods are a stark manifestation of the climate crisis, linking the local vulnerabilities with global responsibilities. This is not an environmental problem but also a legal and human right issue. Science clearly links glacial retreat and lake expansion as human activities. The legal and moral responsibilities are coming into sharper focus. Recent advisory opinions from international and regional courts are clarifying the legal obligations of states to prevent, mitigate, and provide remedy for climate-related harm.
e do not seek sympathy; we demand action. An action that includes binding legal commitments, strong institutions, and meaningful inclusion of young people and vulnerable communities in shaping responses.
The change we hope for is a world where the risks of GLOFs are managed through solidarity, justice, and a shared commitment to safeguarding both people and the planet for future generations. This is not just a climate issue but one of survival, rights, and intergenerational equity. If we fail to respond decisively, the cost will be measured in lost lives, cultures, and ecosystems that will be irreversible. But with meaningful action, informed policy, and empowered youth voices, we can manage these risks and build a safe future.
* The author is a third-year law student of the BBM- LL.B program of Kathmandu University School of Law, Nepal.
DISCLAIMER: The views expressed in the symposium’s blog posts are those of the author and do not represent the views of WYCJ. Furthermore, university chapters were prepared, edited, and approved by the respective universities; WYCJ cannot guarantee the level of scientific and legal inquiry, nor the content of blog posts.