Imported water risk: the case of the UK

While thewater dependency of water-scarce nations is well understood, this is not the case for countries in temperate and humid climates, even though various studies have shown thatmany of such countries strongly rely on the import of water-intensive commodities from elsewhere. In this studywe introduce amethod to evaluate the sustainability and efficiency of the external water footprint (WF) of a country, with theUK as an example.We trace, quantify andmap theUK’s direct and indirect water needs and assess the ‘importedwater risk’ by evaluating the sustainability of the water consumption in the source regions. In addition, we assess the efficiency of thewater consumption in source areas in order to identify the room forwater savings.Wefind that half of the UK’s global blueWF—the direct and indirect consumption of groundand surfacewater resources behind all commodities consumed in theUK—is located in places where the blueWF exceeds the maximum sustainable blueWF. About 55%of the unsustainable part of theUK’s blueWF is located in six countries: Spain (14%), USA (11%), Pakistan (10%), India (7%), Iran (6%), and SouthAfrica (6%). Our analysis further shows that about half of the global consumptiveWFof theUK’s direct and indirect crop consumption is inefficient, whichmeans that consumptiveWFs exceed specifiedWF benchmark levels. About 37%of the inefficient part of theUK’s consumptiveWF is located in six countries: Indonesia (7%), Ghana (7%), India (7%), Brazil (6%), Spain (5%), andArgentina (5%). In some source countries, like Pakistan, Iran, Spain, USA and Egypt, unsustainable and inefficient blue water consumption coincide.We find that, by lowering overall consumptiveWFs to benchmark levels, the global blueWFofUK crop consumption could be reduced by 19%.We discuss four strategies tomitigate importedwater risk: becomemore self-sufficient in food; diversify the import of water-intensive commodities, favouring the sourcing fromwater-abundant regions; reconsider the import of water-intensive commodities from the regions that aremost severely water stressed altogether; and collaborate internationally with source countries with unsustainable water usewhere opportunities exist to increase water productivity.