The Himalayas have more snow and ice than anywhere else outside the poles, which makes this region with all its associated large river systems especially vulnerable to climate change and related impacts. Beside impacts on drinking water supplies and hydro-energy, those on agriculture are of major concern, given that the economy largely depends on agricultural production.
Researchers from SMHI, together with researchers from the National Institute of Hydrology (NIH), India, the Stockholm Environmental Institute (SEI), Sweden, and the Indian Institute of Technology (IIT Delhi), India, investigated the possible climate change impacts on local water availability with the aim to further link these findings to policies for promoting sustainable management of water resources.
Workshop for knowledge sharing
A two-day workshop in Roorkee, India, allowed project partners to disseminate knowledge to stakeholders and the scientific community, with a particular focus on the upper Ganges region. The workshop aimed to develop a solid foundation for locally important water management and adaptation options as well as formulation of integrated river basin development plans, to tackle future climatic conditions. Such information is useful in deciding water allocation and use, highlight areas of particular concern and prevent potential user conflicts in planning for sustainable and efficient water resources management for agriculture, industry, food security and poverty alleviation.
Changes in precipitation and hydro-climatic extremes
The presented results showed that, by the end of the century, Indian-Himalayas could be experiencing up to 40% changes in precipitation, evapotranspiration and runoff, while reductions are expected for snow depths. Hydro-climatic extremes will also be affected with increasing frequency of severe dry and wet years and also flood occurrences.
“The change is of roughly the same magnitude as in previous calculations for the region, highlighting the consistency in the expected changes in the hydrological regimes, and hence improving our confidence of taking important adaptation measures” says Ilias Pechlivanidis, a researcher in hydrology at SMHI and leader of the WaterRain-Him project.
New detailed hydrological projections
The WaterRain-Him project is one of the first of its kind in which researchers will assess the combined impacts from environmental change (climate, land use and population) on water resources and propose suitable adaptation measures. The project will make use of the new detailed regional climate simulations from the CORDEX-SA initiative over the Himalayas. The results will be compared with those of earlier studies of the region performed by other research groups and the WaterRain-Him project partners.
Patrick Büker, a researcher at SEI, remarked: “The project focuses on three large river systems, Indus, Ganges and Brahmaputra, using various environmental change projections and hydrological models. This means that we can incorporate a large range of hypotheses for future scenarios in the hydrological projections and identify the suitable adaptation measures considering the projected uncertainty.”
The key to environmental change adaptation
In a next step, SMHI’s research staff are continuing their work together with Swedish and Indian researchers targeting climate adaptation linked with changed water balance and hydro-climatic extremes.
“Adaptation to a changed environment requires cross-sector cooperation at all levels of society. The local influence of actors involved in planning and decision-making is of course necessary, as well as considering regional and national demands for the consideration of climate variability,” says Ylva Ran, Researcher at SEI.
Climate projections from the CORDEX South-Asia and other initiatives have been used to improve confidence in regional trends of hydro-climatic key variables and increase robustness in hydrological long term predictions. These projections were bias-corrected to be directly useful for assessing impacts at the regional and/or local scale and finally introduced into various hydrological models from SMHI, NIH and IIT Delhi to assess the impact of climate change on water resources in the Ganges basin.