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Trends in extreme events across the HKH

Asia is the most disaster-prone region in the world. In 2014, over 40% of the world’s natural disasters were reported in this region. 69 It is also where most people have been killed, the greatest losses have been incurred, and the most frequent disasters are clustered. Within Asia, the HKH region stands out for its water-related disasters and the human toll these take, especially flooding. Many of the 210 million people living in the Hindu Kush Himalayas and the 1.3 billion people living downstream 70 are exposed to devastating floods every year. Water-related hazards and risks include landslides, debris flows and flash floods in the uplands and riverine and coastal flooding in the lowlands. Across the HKH region, there has been a steady increase in the number of flood disasters reported each decade. 71,72 This last decade saw the highest number of reported flood disasters with the greatest spatial coverage on record. These included the devastating floods in Pakistan in 2010

and the Uttarakhand flood in India in 2013. The 2010 Pakistan floods killed some 2,000 people and submerged about a fifth of Pakistan’s land, affecting the lives of 20 million people. Some 5,900 camps sprung up across the country to host the more than 220,000 people displaced by the disaster. This disaster is considered one of the biggest river disasters in recent history. In general, the economic impact of flood disasters within the HKH region is highest in Pakistan, Afghanistan and Nepal, while loss or injury to human life is highest in Bangladesh, Pakistan, Bhutan and India. 73 At a more localized level, GLOFs pose a significant risk to mountain and downstream communities. Glacier thinning and retreat in the Himalayas has resulted in the formation of new glacial lakes and the enlargement of existing ones due to the accumulation of meltwater behind loosely consolidated end moraine dams. Recent research has shown that many lakes are expanding at a

considerable rate. The number of glacial lakes has been increasing across the region over the last 30 years, from 4,600 in 1990 to 5,700 in 2010, 74 resulting in increasing risks over time for downstream communities and environments. Along with flooding, changing precipitation patterns have also resulted in increased frequency and intensity of droughts in many parts of South Asia. Across the HKH region, ICIMOD’s research shows that the number of rainy days has decreased, but there are more intense rainfall events, while the total amount of annual rainfall has stayed the same. 75 The most vulnerable to the effects of drought are people living in already dry arid and semi-arid regions such as the upper Indus basin, Tibetan plateau and Ladakh, or where groundwater resources are low or scarce such as in the high mountains. As the impacts of climate change increase, these regions will become even more vulnerable to the impacts of drought.

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