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Between 2000 and 2010, groundwater depletion

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caused by irrigation increased 22 percent.

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NASA scientists and colleagues used Earth observations and models

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to understand where this groundwater depletion is most severe.

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The most overexploited aquifers: the North and South Arabian,

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Persian, Western Mexico and Upper Ganges,

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all show evidence of groundwater depletion from irrigation.

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In drier countries like Kuwait, Iran and Saudi Arabia,

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crops require extremely large amounts of groundwater-depleting irrigation to grow.

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For example, rice grown in Pakistan causes eight times more groundwater depletion per unit

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than in India, where surface water resources are more plentiful.

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International trade moves these crops between countries,

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so in some cases, the countries consuming the most groundwater depletion-linked crops

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may have more water supplies, relatively speaking.

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However, importers of groundwater depleting-crops

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face a potential future food supply risk, as overexploited aquifers

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may not be able to continue providing water

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at current levels in the long-term.