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MacDonald A.M.,British Geological Survey | Bonsor H.C.,British Geological Survey | Ahmed K.M.,University of Dhaka | Burgess W.G.,University College London | And 16 more authors.
Nature Geoscience | Year: 2016

Groundwater abstraction from the transboundary Indo-Gangetic Basin comprises 25% of global groundwater withdrawals, sustaining agricultural productivity in Pakistan, India, Nepal and Bangladesh. Recent interpretations of satellite gravity data indicate that current abstraction is unsustainable, yet these large-scale interpretations lack the spatio-temporal resolution required to govern groundwater effectively. Here we report new evidence from high-resolution in situ records of groundwater levels, abstraction and groundwater quality, which reveal that sustainable groundwater supplies are constrained more by extensive contamination than depletion. We estimate the volume of groundwater to 200 m depth to be >20 times the combined annual flow of the Indus, Brahmaputra and Ganges, and show the water table has been stable or rising across 70% of the aquifer between 2000 and 2012. Groundwater levels are falling in the remaining 30%, amounting to a net annual depletion of 8.0 ± 3.0 km3. Within 60% of the aquifer, access to potable groundwater is restricted by excessive salinity or arsenic. Recent groundwater depletion in northern India and Pakistan has occurred within a longer history of groundwater accumulation from extensive canal leakage. This basin-wide synthesis of in situ groundwater observations provides the spatial detail essential for policy development, and the historical context to help evaluate recent satellite gravity data. © 2016 Macmillan Publishers Limited, part of Springer Nature.

Opitz-Stapleton S.,Institute for Social and Environmental Transition International ISET International | Sabbag L.,University of North Carolina at Chapel Hill | Hawley K.,Institute for Social and Environmental Transition International ISET International | Tran P.,ISET Vietnam | And 2 more authors.
Climate Services | Year: 2016

Occupational extreme heat exposure can lead to a number of detrimental heat-health impacts on workers. Excessive night-time temperatures following hot days do not allow for workers to recover and can compound work heat-health impacts. A number of heat indices have been developed to estimate thermal comfort – how hot it feels – based on meteorological, physiological, and working conditions. We investigated potential changes in day and night-time ambient temperatures and heat indices for Da Nang, Vietnam over the period 2020–2049 when compared with 1970–1999 after downscaling daily minimum and maximum temperatures and humidity variables from six CMIP5 climate models. Two heat indices were employed, the U.S. National Weather Service Heat Index for day and the indoor Apparent Temperature for night. The Vietnam Ministry of Health (MOH) sets thermal comfort thresholds for particular workloads and rates. By 2050, daytime heat index values breach the average 32 °C MOH threshold for light work nearly continuously during the months of April to October. The number of nights per annum in which the heat index exceeds 28 °C is likely to range between 131 and 170 nights per year. Occupational heat exposure in Da Nang for outdoor workers or indoor workers without adequate ventilation, breaks or other cooling and heat precautionary and treatment measures will be exacerbated by climate change. © 2016 Institute for Social and Environmental Transition - International

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