According to a significant new assessment report from an eight-nation body called the International Centre for Integrated Mountain Development (ICIMOD), the changes to the glaciers, snow, and permafrost of the Hindu Kush Himalayan (HKH) region brought on by global warming are "unprecedented and largely irreversible."

The research project Water, Ice, Society, and Ecosystems in the Hindu Kush Himalaya (HI-WISE) makes use of recent advances in science to map for the first time the relationships between the cryosphere, water, biodiversity, and society in the area, as well as the effects of glacier and snow changeovers that occur quickly on people and the environment.

According to the report, based on current emission trajectories, the HKH's glaciers could lose up to 80% of their current volume by the end of the century.

Under high emissions scenarios, snow cover is expected to decrease by up to a quarter, drastically reducing freshwater for important rivers like the Amu Darya, where it contributes up to 74% of river flow, the Indus (40%) and Helmand (77%), among others. Permafrost coverage is shrinking, which will increase landslides and cause issues for high-altitude infrastructure. The Hindu Kush Himalayan glaciers disappeared 65% faster in 2011–2020 compared with the previous decade.

The study cautions that current funding flows to the region are woefully inadequate to the scale of the challenges the region will face. Communities and governments need urgent support and financing to prepare for the accelerated impacts on societies and nature that cryosphere changes will cause as temperatures rise.

Scientists anticipate catastrophic effects on energy supplies, ecosystems, water and food security, and the lives and livelihoods of hundreds of millions of people throughout Asia, many of whom will be unable to adapt.

With a new paper showing Arctic waters could lose all of their summer-end sea ice as early as 2030, cryosphere scientists at the Bonn Climate Change Conference raised the alarm about the speed and scale of ice-melt worldwide, which is far outpacing worst-case scenario projections from the IPCC. This led to the publication of the report.

Deputy Director General of ICIMOD Izabella Koziell stated, "Observations in the Arctic and the anomalies we are seeing elsewhere in the cryosphere have climate scientists in a state of shock. The Hindu Kush Himalayan glaciers are a significant part of the Earth's system. The effects of losing this cryosphere are too great to consider given that two billion people in Asia depend on the water that these glaciers and snowpack store. We need leaders to act now to prevent catastrophe.”

“There is still time to save this critical region, but only if fast and deep emissions cuts start now. Every increment of a degree of warming matters to glaciers here and to the hundreds of millions of people that depend on them. As this study shows, alongside urgent mitigation action, we need adaptation funds and programmes and ecosystem restoration to be rapidly scaled up, and the mobilisation of finance for losses and damages.”

Hindu Kush covered in ice and snow In addition to providing freshwater and other essential ecosystem services to 240 million people in the mountains and another 1.65 billion people downstream, the Himalaya are a significant source of water for 12 rivers that flow through 16 countries in Asia.

Major negative effects, such as disasters that cause loss and damage to lives, property, heritage, and infrastructure, force eviction, and have psychological repercussions, are already having a significant negative impact on vulnerable mountain communities.

“Current adaptation efforts are wholly insufficient to meet the challenges posed by cryospheric change and the extreme events that we now know with a high degree of certainty will hit these already vulnerable communities with greater magnitude and complexity. We are extremely concerned that without greater support, these communities will be unable to cope. Adaptation needs to be urgently scaled up,” said Amina Maharjan, Senior Livelihoods Specialist at ICIMOD.

According to the study, water availability in the HKH is predicted to reach its peak in the middle of the century as a result of accelerated glacial melt. Thereafter, it is expected to decline, with huge uncertainty for mountain communities and sizable populations in the lowlands due to variability in meltwater from glaciers and snow.

Over the next few decades, it is expected that there will be an increase in both floods and landslides, with fast-onset hazards like glacial lake outburst floods (GLOFs) and slow-onset hazards like erosion and sedimentation frequently occurring simultaneously in the same catchments. By the end of the century, the HKH could experience a significant increase in GLOF risk due to the 200 glacier lakes that are considered dangerous. The exposure to these hazards raises the possibility of greater loss and damage, including population displacement, when combined with the region's increased economic activity and population growth.

According to the report, the impacts of the changing cryosphere on the sensitive mountain habitats are particularly severe, with cascading effects being observed in the majority of ecosystems and affecting the majority of resident species. Species decline and extinction have already been reported, along with range shift of species to higher elevations, ecosystem degradation, decrease in habitat suitability, and invasion of alien species.

With 67% of the HKH’s ecoregions and 39% of the four global biodiversity hotspots located in the HKH remaining outside protected areas, nature is particularly vulnerable to climate impacts.

The report warns policymakers need to prepare for the cascading impacts of climate change in the critical mountain biome, which will affect a quarter of the world’s population. Urgent international support and regional cooperation is now vital to deal with inevitable, near-term loss and damage, and to help communities’ adaptation efforts.

Professor Saleemul Huq, Director of the International Centre for Climate Change and Development, Bangladesh, and on the Advisory Board to COP28, said, “In all three pillars of climate action – in mitigation, adaptation and loss and damage – we are at a standstill or going the wrong way; while the consequences of inaction are accelerating by the day. This report zeroes in on the devastating implications this will have on two billion people and the nature that rely on the water and ecosystems of the Hindu Kush Himalaya. It is beyond time that Governments, donors and agencies step up: to exit fossil fuels and honour their commitments to limit warming, to help communities adapt to those temperature rises already locked in and to compensate them for property and ways of life that have already been lost.”

Pam Pearson, Director of the International Cryosphere Climate Initiative (ICCI), said, “There have been huge strides in cryosphere science since the Paris Agreement was agreed. We understand today what we did not fully appreciate then: that ice responds much more quickly and irreversibly to temperature rises than previously thought. It’s crucial for governments and civil society to be aware of the extreme implications of even just 1.5 °C degrees of warming on the cryosphere. Because it is clear that billions of people’s lives now depend on our urgent pursuit of very low emissions pathways. This is the only way to slow or avoid catastrophic impacts.”

The full report can be accessed here