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Rising temperatures caused by the burning of gas, coal and oil are leading to increasing number of unpredictable floods across High Mountain Asia, in the heart of the continent, according to a new study.
While the frequency of floods has arisen since 2000, so has the unpredictability in their timing, as per the study. While most events continue to occur during monsoon, there is a marked rise in the number of floods happening outside these times, according to a statement by ICIMOD.
The study, titled Flood complexity and rising exposure risk in High Mountain Asia under climate change, analysed 1,015 floods in High Mountain Asia.
Authored by Peking University’s Dongfeng Yi, ICIMOD Cryosphere Specialist Sonam Wangchuk, Peking University Yuanyuan Bai, University of Colorado’s Albert J Kettner, the study is grounded in a new inventory of the types, patterns and causes of floods in the region stretching back to 1950.
The study focusses on four distinct type of floods: Rain/Pluvial-induced floods triggered by heavy rainfall which results in surface runoff and flash floods; snowmelt-induced floods which occur when rising temperatures accelerate snowmelt and increasing river discharge; glacial lake outburst floods (GLOFs) caused by glacial lakes overflow or breach, often due to melting glaciers or landslides and Landslide-dammed Lake outburst floods (LLOFs), often the results of landslides blocking rivers, creating temporary lakes that might breach.
“[While] pluvial and snowmelt floods... result from extreme rainfall,” report author Dongfeng Li, principal investigator of the Cryosphere and River Lab at Peking University, stated, “snowmelt floods are driven by rising temperatures and increased soil moisture. In contrast GLOFs and LLOFs [are] shaped by complex interactions between climate, glaciers, and topography.”
Human activities are hugely aggravating the risks from floods, especially urbanisation and land use changes, such as human settlements in flood plains, deforestation, and dams, can all increase vulnerability and reduce natural buffers, as per the statement.
The study’s authors urged greater emphasis on community-based flood mitigation efforts including community awareness programs, locally led construction of protective infrastructure, and local emergency planning.
“We should prioritise real-time monitoring of floods in vulnerable valleys, restrict infrastructure projects in high-risk zones, and strengthen data-sharing agreements between High Mountain Asia nations to address transboundary threats,” said one of the authors of the report, Sonam Wangchuk.
The study is published in February’s edition of Science Bulletin, a peer-reviewed international journal, which is sponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China.