High Mountain Asia (HMA) shows a remarkable warming tendency and divergent trend of regional precipitation with enhanced meteorological extremes. The rapid thawing of the HMA cryosphere may alter the magnitude and frequency of nature hazards. We reviewed the influence of climate change on various types of nature hazards in HMA region, including their phenomena, mechanisms and impacts. It reveals that: 1) the occurrences of extreme rainfall, heavy snowfall, and drifting snow hazards are escalating; accelerated ice and snow melting have advanced the onset and increased the magnitude of snowmelt floods; 2) due to elevating trigger factors, such as glacier debuttressing and the rapid shift of thermal and hydrological regime of bedrock/snow/ice interface or subsurface, the mass flow hazards including bedrock landslide, snow avalanche, ice-rock avalanches or glacier detachment, and debris flow will become more severe; 3) increased active-layer detachment and retrogressive thaw slumps slope failures, thaw settlement and thermokarst lake will damage many important engineering structures and infrastructure in permafrost region; 4) multi-hazards cascading hazard in HMA, such as the glacial lake outburst flood (GLOF) and avalanche-induced mass flow may greatly enlarge the destructive power of the primary hazard by amplifying its volume, mobility, and impact force; and 5) enhanced slope instability and sediment supply in the highland areas could impose remote catastrophic impacts upon lowland regions, and threat hydropower security and future water shortage. In future, ongoing thawing of HMA will profoundly weaken the multiple-phase material of bedrock, ice, water, and soil, and enhance activities of nature hazards. Compounding and cascading hazards of high magnitude will prevail in HMA. As the glacier runoff overpasses the peak water, low flow or droughts in lowland areas downstream of glacierized mountain regions will became more frequent and severe. Addressing escalating hazards in the HMA region requires tackling scientific challenges, including understanding multiscale evolution and formation mechanism of HMA hazard-prone systems, coupling thermo-hydro-mechanical processes in multi-phase flows, predicting catastrophes arising from extreme weather and climate events, and comprehending how highland hazards propagate to lowlands due to climate change.

Coastal inundation causes considerable impacts on communities and economies. Sea level rise due to climate change increases the occurrence of coastal flood events, creating more challenges to coastal societies. Here we intend to draw the understanding of coastal inundation from our early studies, and provide a silhouette of our approaches in assessing climate change impacts as well as developing risk-based climate adaptation. As a result, we impart a distinctive view of the adaption towards the integration of asset design, coastal planning and policy development, which reflect multiscale approaches crossing individual systems to regions and then nation. Having the approaches, we also discussed the constraints that would be faced in adaptation implementation. In this regard, we initially follow the risk approach by illustrating hazards, exposure and vulnerability in relation to coastal inundation, and manifest the impact and risk assessment by considering an urban environment pertinent to built, natural, and socioeconomic systems. We then extend the scope and recommend the general approaches in developing adaptation to coastal inundation under climate change towards ameliorating overall risks, practically, by the reduction in exposure and vulnerability in virtue of the integration of design, planning and polices. In more details, a resilience design is introduced, to effectively enhance the capacity of built assets to resist coastal inundation impact. We then emphasize on the cost-effective adaptation for coastal planning, which delineates the problem of under-adaptation that leaves some potential benefits unrealized or over-adaptation that potentially consumes an excessive amount of resources. Finally, we specifically explore the issues in planning and policies in mitigating climate change risks, and put forward some emerging constraints in adaptation implementation. It suggests further requirements of harmonizing while transforming national policies into the contents aligned with provincial and local governments, communities, and households.

The study analyzed synthetically spatiotemporal distribution and evolution status of moraine-dammed lakes and potential dangerous glacial lakes (PDGLs) in the Qinghai-Tibetan Plateau (QTP) and revealed integrated risk degree of county-based glacier lake outburst floods (GLOFs) disaster by combining hazard of PDGLs, regional exposure, vulnerability of exposed elements, and adaptability and using the analytic hierarchy process and weighted comprehensive method. The results show there are 654 moraine-dammed lakes (> 0.018 km(2)) with a total area of 200.25 km(2)in the QTP in the 2010s, of which 246 lakes with a total area of 78.38 km(2)are identified as PDGLs. Compared with 1990s, the number of lakes decreased only by 2.22%, whereas total lake area expanded by 25%. All PDGLs area increased by 84.40% and was higher significantly than 4.06% of non-PDGLs. The zones at very high and high integrated risk of GLOF disasters are concentrated on the middle Himalayas, middle-eastern Nyainqentanglha, and southern Tanggula Mountain. On the county scale, Nyalam, Tingri, Dinggye, Lhozhag, Zhongba, Gamba, Kangma of the Himalayas, and Nierong, Dingqing, Banbar, Baqing, Bomi, and Basu of the Nyainqentanglha are located in the very high-risk zone, whereas other areas have low and very low integrated risk. The regionalization results for GLOF disasters risk are consistent with the distribution of historical GLOF disaster sites.