Projected impacts of climate change on farmers' extraction of groundwater from crystalline aquifers in South India

Sylvain Ferrant (1, 2) , Yvan Caballero (3) , Jérome Perrin (3, 4) , Simon Gascoin (2) , Benoît Dewandel (3) , Stéphanie Aulong (3) , Fabrice Dazin (5) , Shakeel Ahmed (4) , Jean-Christophe Maréchal (3)

1 LEFE - Laboratoire Ecologie Fonctionnelle et Environnement
2 CESBIO - Centre d'études spatiales de la biosphère
3 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
4 IFCGR - Indo-French Center for Groundwater Research
5 SIRS

Local groundwater levels in South India are falling alarmingly. In the semi-arid crystalline Deccan plateau area, agricultural production relies on groundwater resources. Downscaled Global Climate Model (GCM) data are used to force a spatially distributed agro-hydrological model in order to evaluate Climate Change (CC) effects on local groundwater extraction (GWE). The slight increase of precipitation may alleviate current groundwater depletion on average, despite the increased evaporation due to warming. Nevertheless, projected climatic extremes create worse GWE shortages than for present climate. Local conditions may lead to opposing impacts on GWE, from increases to decreases (+/-20 mm/year), for a given spatially homogeneous CC forcing. Areas vulnerable to CC in terms of irrigation apportionment are thus identified. Our results emphasize the importance of accounting for local characteristics (water harvesting systems and maximal aquifer capacity versus GWE) in developing measures to cope with CC impacts in the South Indian region.

Domaines: Sciences de la Terre

Sylvain Ferrant, Yvan Caballero, Jérome Perrin, Simon Gascoin, Benoît Dewandel, et al.. Projected impacts of climate change on farmers' extraction of groundwater from crystalline aquifers in South India. Scientific Reports, 2014, 4, pp.3697. ⟨10.1038/srep03697⟩. ⟨hal-01176464⟩