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Himalayan glaciers could lose up to 80% of their ice by 2100 as temperatures rise, report warns
The world’s highest peaks are at risk of losing up to 80% of their volume by the end of the century with profound consequences for millions of people under worst case climate scenarios, international scientists in Nepal warned in a new report.
The report, published Tuesday by the International Centre for Integrated Mountain Development (ICIMOD), examined the impact of climate change on an area stretching 1.6 million square miles (4.1 million square kilometers) from Afghanistan in the west to Myanmar in the east.
The report found that glaciers in the Hindu Kush and Himalaya mountain range region melted 65% faster in the 2010s compared with the previous decade, which suggests higher temperatures are already having an impact.
Ice and snow in the region feeds 12 rivers that provide freshwater to two billion people in 16 countries, including China, India and Pakistan, and eventually too much water will eventually lead to too little, the report warns.
The same group published a report in 2019, which found that even in the most optimistic case, where average global warming was limited to 1.5 degrees Celsius above pre-industrial temperatures, the region would lose at least one third of its glaciers.
The group’s updated report shows those projections have since worsened.
With between 1.5 to 2 degrees Celsius of warming, the world’s highest mountain region stands to lose 30% to 50% of its volume by 2100, the latest report said.
If the world breaches 3 degrees Celsius of warming, glaciers in Nepal and Bhutan in the eastern Himalayas are at risk of losing 75% of their ice, and by just one degree more, that ticks up to 80%, according to the report.
The annual mean global near-surface temperature for each year between 2023 and 2027 is predicted to be between 1.1 degrees Celsius and 1.8 degree Celsius higher than the 1850-1900 average, according to the World Meteorological Organization
Scientists consider 1.5 degrees of warming as a key tipping point, beyond which the chances of extreme flooding, drought, wildfires and food shortages could increase dramatically.
“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,” Prof. Saleemul Huq, director of the International Centre for Climate Change and Development in Bangladesh was quoted as saying in the report.
Rapid warming and glacial melt
About 240 million people live in the Hindu Kush Himalaya region, many of their cultures dating back thousands of years, and another the 1.65 billion live downstream.
Many high mountain communities depend on glacial waters to irrigate crops and to maintain their livestock, but the accelerated melting would inundate farmlands downstream followed by periods of drought as water sources dry up, the report said.
The erosion of glacial slopes also heightens the likelihood of floods, landslides and avalanches, increasing the risk to millions living in mountain communities.
“For them, this is home, and their livelihoods are mostly dependent on agriculture, livestock, tourism, and medicinal and aromatic plants,” report co-author Amina Maharjan, a senior specialist in livelihoods and migration at ICIMOD.
“What we realized in doing this assessment is that all of these are very, very sensitive to slight changes in climatic conditions and cryospheric conditions in the region,” she said.
For example, snowfall patterns are increasingly out of sync with seasonality, blanketing pastures and shrinking the grazing land for livestock, Maharjan explained. Over the past half decade, yaks have died due to a lack of food in India, Nepal and Bhutan, leaving farmers with huge income loses, she added.
The remoteness and rough terrain of the region also means that mountain communities often lack access to immediate disaster response.
“The glaciers of the Hindu Kush Himalaya are a major component of the Earth system. With two billion people in Asia reliant on the water that glaciers and snow here hold, the consequences of losing this cryosphere are too vast to contemplate. We need leaders to act now to prevent catastrophe,” said Izabella Koziell, deputy director general of the ICIMOD.
Unique species are also threatened by adverse changes to the climate of the diverse ecosystems that include tropical and subtropical rainforests, temperate coniferous forest and cold deserts, the report said.
Fourteen species of butterflies have already become extinct from the Murree Hills of Pakistan, according to the report, while endemic frog species are among the most impacted by climate change as they experience breeding problems and developmental deformities.
注释：
tick: v
表示"运转，进行，持续活动"，means "go"，如：That's what makes the world tick. 使世界持续活动的动力，就在于此。
tipping point: n
表示" 引爆点；卸载点"，如：It's not clear yet that this is the beginning of the feared shutdown, but if so, it represents yet another tipping point. 现在还不清楚这是否是可怕的终止的开始，但是如果是的话，那么它代表着另一个引爆点。
inundate: v
表示"淹没"，means "fill or cover completely, usually with wate"，如：The course changes frequently, and the area is so flat that a small change in the level of the river may inundate a considerable area. 河道变化多端，下游地区却很平坦，水位少许上涨河流就会淹没一大片土地
avalanche: n
表示" 雪崩"，means "a slide of large masses of snow and ice and mud down a mountain"，如：Three climbers are safe after the avalanche. 雪崩过后，三个登山者平安无事。
cryospheric: adj
表示"冰冻圈,低温层"，如：Visitors to the SOCC site can access current and past cryospheric datasets, educational materials, meeting presentations, a gallery of cryospheric photos, and links to cryospheric-related resources. 通过该网站，访问者可以获得冰冻圈数据集、教育资料、会议资料、照片集、以及冰冻圈相关资源的网址链接。
subtropical: adj
表示" 亚热带的"，means "of or relating to or characteristic of conditions in the subtropics"，如：This country has a subtropical climate. 这个国家属于亚热带气候。
coniferous: adj
表示"松类的；结球果的"，如：A resin derived from the sap of various coniferous trees, as the pines. 松脂，树脂某种松脂，自某些针叶树（如松树）上提取
endemic: n
表示"地方病；风土病"，如：Endemic diseases are common in this area. 这个地区地方病流行。
deformity: n
表示" 畸形；残废"，如：A hump is caused by a deformity of the spine. 驼背是脊椎骨畸形所致。
中文简要说明：
气候变迁不仅对人类生存造成威胁，物种生态也饱受冲击。科学家指出，一种生长于喜马拉雅山脉、拥有3.9亿年历史，堪称全球最古老的「藻苔」植物挺过多次生物大灭绝，却可能捱不过暖化灾难，正以每年减少1.6%的速度走向绝种。
根据英国《卫报》报导，早在喜马拉雅山脉形成以前，藻苔属植物（Takakia）就已在当地存在了1亿年，它的生长速度缓慢、数量稀少，只存在美国、日本和西藏偏远地区，却因为生长环境太过严苛，反而发展出良好的适应力，成为世界上进化最快的物种之一。
研究团队指出，藻苔属植物已存在3.9亿年，称作植物界的「活化石」一点也不为过。这种植物可自行修复受损的DNA，也能在晒伤后复原，甚至发展出灵活的「分枝系统」（branching system），形成坚固的族群结构，抵御暴风雪侵袭。
不过，由于全球暖化加速，专家发现，藻苔属植物正遭受更强烈的紫外线照射，其生长环境的冰川也快速融化，导致栖地大幅减少。过去10年来，西藏地区的藻苔属植物每年减量约1.6%，预估本世纪末，全球各地将只剩下1000至1500平方公里地区适合藻苔属植物生存。科学家目前正尝试取部分样本移往实验室繁殖，以避免发生「物种灭绝」
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