Your search found 6 records
1 Pekel, J.-F.; Cottam, A.; Gorelick, N.; Belward, A. S. 2016. High-resolution mapping of global surface water and its long-term changes. Nature, 540(7633):418-422. [doi: https://doi.org/10.1038/nature20584]
Surface water ; Mapping ; Satellite imagery ; Landsat ; Earth observation satellites ; Water distribution ; Geographical distribution ; Seasonal variation ; Expert systems ; Climate change ; Hydrology ; Models ; Drought ; Evaporation ; Human behavior ; Lakes ; Plateaus / Central Asia / USA / Australia / Aral Sea / Tibetan plateau
(Location: IWMI HQ Call no: e-copy only Record No: H047905)
(8.75 MB)
The location and persistence of surface water (inland and coastal) is both affected by climate and human activity1 and affects climate2,3 , biological diversity4 and human wellbeing5,6 . Global data sets documenting surface water location and seasonality have been produced from inventories and national descriptions7 , statistical extrapolation of regional data8 and satellite imagery9–12, but measuring long-term changes at high resolution remains a challenge. Here, using three million Landsat satellite images13, we quantify changes in global surface water over the past 32 years at 30-metre resolution. We record the months and years when water was present, where occurrence changed and what form changes took in terms of seasonality and persistence. Between 1984 and 2015 permanent surface water has disappeared from an area of almost 90,000 square kilometres, roughly equivalent to that of Lake Superior, though new permanent bodies of surface water covering 184,000 square kilometres have formed elsewhere. All continental regions show a net increase in permanent water, except Oceania, which has a fractional (one per cent) net loss. Much of the increase is from reservoir filling, although climate change14 is also implicated. Loss is more geographically concentrated than gain. Over 70 per cent of global net permanent water loss occurred in the Middle East and Central Asia, linked to drought and human actions including river diversion or damming and unregulated withdrawal15,16. Losses in Australia17 and the USA18 linked to long-term droughts are also evident. This globally consistent, validated data set shows that impacts of climate change and climate oscillations on surface water occurrence can be measured and that evidence can be gathered to show how surface water is altered by human activities. We anticipate that this freely available data will improve the modelling of surface forcing, provide evidence of state and change in wetland ecotones (the transition areas between biomes), and inform water-management decision-making.
2 Wester, P.; Mishra, A.; Mukherji, A.; Shrestha, A. B. (Eds.) 2019. The Hindu Kush Himalaya assessment: mountains, climate change, sustainability and people. Cham, Switzerland: Springer. 627p. [doi: https://doi.org/10.1007/978-3-319-92288-1]
Climate change ; Mountains ; Sustainable Development Goals ; Living standards ; Natural Resources ; Water availability ; Water use ; Groundwater ; Water governance ; Food security ; Nutrition ; Natural disasters ; Disaster risk reduction ; Resilience ; Ecosystem services ; Biodiversity conservation ; Urbanization ; Land use ; Land cover change ; Air pollution ; Air quality ; Weather forecasting ; Temperature ; Precipitation ; Energy demand ; Energy policies ; Gender ; Communities ; Decision making ; Assessment ; Environmental sustainability ; Glaciers ; Watersheds ; Rivers ; Snow ; Infrastructure ; Indicators ; Economic growth ; Models / South Asia / Afghanistan / Bangladesh / Bhutan / Pakistan / India / Nepal / Myanmar / China / Hindu Kush Himalayan Region / Tibetan Plateau
(Location: IWMI HQ Call no: e-copy only Record No: H049457)
https://link.springer.com/content/pdf/10.1007%2F978-3-319-92288-1.pdf
https://vlibrary.iwmi.org/pdf/H049457.pdf
https://vlibrary.iwmi.org/pdf/H049457.pdf
(28.30 MB) (28.3 MB)
3 Fan, X.; Miao, C.; Duan, Q.; Shen, C.; Wu, Y. 2021. Future climate change hotspots under different 21st century warming scenarios. Earth’s Future, 9(6):e2021EF002027. [doi: https://doi.org/10.1029/2021EF002027]
Climate change ; Forecasting ; Global warming ; Extreme weather events ; Precipitation ; Temperature ; Emission ; Models ; Uncertainty ; Indicators / Central Africa / West Africa / Southern Africa / Central America / Arctic Region / Indonesia / Tibetan Plateau / Amazon
(Location: IWMI HQ Call no: e-copy only Record No: H050397)
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2021EF002027
https://vlibrary.iwmi.org/pdf/H050397.pdf
https://vlibrary.iwmi.org/pdf/H050397.pdf
(4.65 MB) (4.65 MB)
Identifying climate change hotspot regions is critical for planning effective mitigation and adaptation activities. We use standard Euclidean distance (SED) to calculate integrated changes in precipitation and temperature means, interannual variability, and extremes between different future warming levels and a baseline period (1995–2014) using the Coupled Model Intercomparison Project Phase 6 (CMIP6) climate model ensemble. We find consistent hotspots in the Amazon, central and western Africa, Indonesia and the Tibetan Plateau at warming levels of 1.5 °C, 2 °C and 3 °C for all scenarios explored; the Arctic, Central America and southern Africa emerge as hotspots at 4 °C warming and at the end of the 21st century under two Shared Socioeconomic Pathways scenarios, SSP3-7.0 and SSP5-8.5. CMIP6 models show higher SED values than CMIP5, suggesting stronger aggregated effects of climate change under the new scenarios. Hotspot time of emergence (TOE) is further investigated; TOE is defined as the year when the climate change signal first exceeds the noise of natural variability in 21st century projections. The results indicate that TOEs for warming would occur over all primary hotspots, with the earliest occurring in the Arctic and Indonesia. For precipitation, TOEs occur before 2100 in the Arctic, the Tibetan Plateau and Central America. Results using a geographical detector model show that patterns of SED are shaped by extreme hot and dry occurrences at low-to-medium warming, while precipitation and temperature means and extreme precipitation occurrences are the dominant influences under the high emission scenario and at high warming levels.
4 Khanal, S.; Lutz, A. F.; Kraaijenbrink, P. D. A.; van den Hurk, B.; Yao, T.; Immerzeel, W. W. 2021. Variable 21st century climate change response for rivers in high mountain Asia at seasonal to decadal time scales. Water Resources Research, 57(5):e2020WR029266. [doi: https://doi.org/10.1029/2020WR029266]
Climate change ; River basins ; Mountains ; Hydrology ; Models ; Time series analysis ; Water availability ; Precipitation ; Glaciers ; Snow cover ; Rainfall-runoff relationships ; Temperature ; Monsoons ; Discharges / Asia / Amu Darya Basin / Balkash Basin / Brahmaputra Basin / Ganges Basin / Helmand Basin / Indus Basin / Irrawaddy Basin / Mekong Basin / Salween Basin / Syr Darya Basin / Tarim Basin / Yangtze Basin / Yellow River / Tibetan Plateau
(Location: IWMI HQ Call no: e-copy only Record No: H050398)
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2020WR029266
https://vlibrary.iwmi.org/pdf/H050398.pdf
https://vlibrary.iwmi.org/pdf/H050398.pdf
(4.00 MB) (4.00 MB)
The hydrological response to climate change in mountainous basins manifests itself at varying spatial and temporal scales, ranging from catchment to large river basin scale and from sub-daily to decade and century scale. To robustly assess the 21st century climate change impact for hydrology in entire High Mountain Asia (HMA) at a wide range of scales, we use a high resolution cryospheric-hydrological model covering 15 upstream HMA basins to quantify the compound effects of future changes in precipitation and temperature based on the range of climate change projections in the Coupled Model Intercomparison Project Phase 6 climate model ensemble. Our analysis reveals contrasting responses for HMA's rivers, dictated by their hydrological regimes. At the seasonal scale, the earlier onset of melting causes a shift in the magnitude and peak of water availability, to earlier in the year. At the decade to century scale, after an initial increase, the glacier melt declines by the mid or end of the century except for the Tarim river basin, where it continues to increase. Despite a large variability in hydrological regimes across HMA's rivers, our results indicate relatively consistent climate change responses across HMA in terms of total water availability at decadal time scales. Although total water availability increases for the headwaters, changes in seasonality and magnitude may diverge widely between basins and need to be addressed while adapting to future changes in a region where food security, energy security as well as biodiversity, and the livelihoods of many depend on water from HMA.
5 Xiao, H.; Tang, Y.; Li, H.; Zhang, L.; Ngo-Duc, T.; Chen, D.; Tang, Q. 2021. Saltwater intrusion into groundwater systems in the Mekong Delta and links to global change. Advances in Climate Change Research, 12(3):342-352. [doi: https://doi.org/10.1016/j.accre.2021.04.005]
Saltwater intrusion ; Groundwater ; Climate change ; Human activity ; Surface water ; Freshwater ; Salinity ; Sea level ; Precipitation ; Pumping ; Wells ; Deltas ; Cyclones / South East Asia / Vietnam / Mekong Delta / Mekong River Basin / Tibetan Plateau
(Location: IWMI HQ Call no: e-copy only Record No: H050591)
https://www.sciencedirect.com/science/article/pii/S1674927821000708/pdfft?md5=84b9faeb3898035203d1bb3899396452&pid=1-s2.0-S1674927821000708-main.pdf
https://vlibrary.iwmi.org/pdf/H050591.pdf
https://vlibrary.iwmi.org/pdf/H050591.pdf
(2.65 MB) (2.65 MB)
In recent decades, changes in temperature, wind, and rainfall patterns of Southeast Asia induced by climate warming in the Tibetan Plateau result in many environmental changes that have serious impacts on the lower reach of the Mekong River basin, a region already battling severe water-related environmental problems such as pollution, saltwater intrusion, and intensified flooding. In the densely populated Mekong Delta located at the mouth of the Mekong River basin in southern Vietnam, the hydrogeological systems have been transformed from an almost undisturbed to a human-impacted state and saltwater intrusion into surface water and groundwater systems has grown to be a detrimental issue recently, seriously threatening freshwater supply and degrading the eco-environment. In this article, the impacts of human activities and climate change (e.g., groundwater over-exploitation, relative sea-level rise, storm surge, changing precipitation and temperature regimes, uncontrolled drainage canals, operation of hydropower dams, and rapid development of aquaculture) on saltwater intrusion into groundwater systems in the Mekong Delta are briefly reviewed. Based on current status of research findings regarding saltwater intrusion and the subsequent groundwater quality degradation under the impacts of human activities and climate change, major knowledge gaps and challenges are identified and discussed, including thickness and permeability of the silt and clay aquitard, present-day highly heterogeneous 3D distribution of saline groundwater zones, dynamic variation of saltwater/freshwater transition zone, and the most effective and economical control measure. To bridge these gaps, future work should: 1) apply environmental isotope techniques in combination with borehole tests to gain detailed hydrogeological information regarding spatial variation of permeability and thickness of the silt and clay aquitard; 2) intensify regular groundwater monitoring and collect as much groundwater samples from multiple hydro-stratigraphic units at different depths as possible to visualize the present-day highly heterogeneous 3D distribution of saline groundwater; 3) develop a series of variable-density coupled groundwater flow and salt transport models representing various scenarios of human activities and climate change for predicting future extent of saltwater intrusion; and 4) identify the dominant factor causing saltwater intrusion and determine the most effective and economical engineering technique to address saltwater intrusion problems in the Mekong Delta.
6 Wang, L.; Zhang, F.; Nepal, Santosh; Xiang, Y.; Tang, H.; Shi, X.; Zeng, C.; Ahmad, I.; Yu, Z. 2023. Response of runoff processes to temperature rise in basins with different glacier ratios in the monsoon-influenced southern Tibetan Plateau. Journal of Hydrology: Regional Studies, 45:101299. [doi: https://doi.org/10.1016/j.ejrh.2022.101299]
River basins ; Runoff ; Temperature ; Glaciers ; Monsoons ; Forecasting / Asia / Tibetan Plateau / Karuxung River Basin / Dudh Koshi River Basin / Arun River Basin / Gandaki River Basin / Lhasa River Basin
(Location: IWMI HQ Call no: e-copy only Record No: H051663)
https://www.sciencedirect.com/science/article/pii/S2214581822003123/pdfft?md5=aad81fb593686cfca687574039f2915b&pid=1-s2.0-S2214581822003123-main.pdf
https://vlibrary.iwmi.org/pdf/H051663.pdf
https://vlibrary.iwmi.org/pdf/H051663.pdf
(9.56 MB) (9.56 MB)
Study region: River basins with glacier ratios ranging from 1.8% to 20.7% in the monsoon-influenced southern Tibetan Plateau.
Study focus: The response of runoff processes in basins with different glacier ratios under global warming of 1.5 C and 2 C was explored based on SPHY (Spatial Processes in Hydrology) model and GCMs (General Circulation Models).
New hydrological insights for the region: More prominent temperature and precipitation changes were observed in the monsoon-influenced southern Tibetan Plateau compared with the global averages. With increasing temperature and precipitation, the total runoff and glacier runoff of these basins showed increasing trends under global warming of 1.5 C and 2 C. Compared with the baseline period (1985–2014), increases were observed in the total runoff (1.7–20.6%), base flow (2.8–8.3%), glacier runoff (8.1–35.9%), and rainfall runoff (6.0–36.0%) of these basins. In contrast, snowmelt runoff decreased (- 28.3% - - 4.3%). Therefore, relevant management and allocation of water resources may be required. The hydrological regulation function of glaciers was found to be strongly correlated with glacier ratio. In general, the hydrological regulation function of glaciers would decrease in the future along with warming induced glacier retreat. These findings would help deepen the understanding of runoff processes on the Tibetan Plateau and other alpine regions, thus providing a scientific basis for water resources management under climate change.
Study focus: The response of runoff processes in basins with different glacier ratios under global warming of 1.5 C and 2 C was explored based on SPHY (Spatial Processes in Hydrology) model and GCMs (General Circulation Models).
New hydrological insights for the region: More prominent temperature and precipitation changes were observed in the monsoon-influenced southern Tibetan Plateau compared with the global averages. With increasing temperature and precipitation, the total runoff and glacier runoff of these basins showed increasing trends under global warming of 1.5 C and 2 C. Compared with the baseline period (1985–2014), increases were observed in the total runoff (1.7–20.6%), base flow (2.8–8.3%), glacier runoff (8.1–35.9%), and rainfall runoff (6.0–36.0%) of these basins. In contrast, snowmelt runoff decreased (- 28.3% - - 4.3%). Therefore, relevant management and allocation of water resources may be required. The hydrological regulation function of glaciers was found to be strongly correlated with glacier ratio. In general, the hydrological regulation function of glaciers would decrease in the future along with warming induced glacier retreat. These findings would help deepen the understanding of runoff processes on the Tibetan Plateau and other alpine regions, thus providing a scientific basis for water resources management under climate change.
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