Given that agriculture accounts for 70 percent of global water usage, any chance we have of improving life for the 4 billion people around the world that live with severe water scarcity for at least one month a year will depend on our ability to adapt our farming and consumption habits. As a first step towards that goal, Oxfam has just released a report indicating that rice and wheat use up more water than the rest of the world’s crops combined.

As the graphs and infographics below indicate, the production of these two common foodstuffs guzzles up a huge proportion all global water usage. Rice, for instance, uses up 40 percent of all irrigation water worldwide.

Graph showing the water scarcity footprint of various crops. Oxfam

Naturally, this is largely because rice and wheat are the most common crops grown around the world, and therefore provide a significant pay-off for their water usage, by feeding more of the world’s population than any other type of food.

However, according to the report, rice, wheat and tea are the three most water intensive commodities, requiring the most hydration per tonne. Because of this, the authors of the report urge farmers and scientists around the world to continue developing more water-efficient production techniques, while also creating drought-resistant strains of key crops.

Comparing the water scarcity footprints of various crops. Oxfam

For instance, the System of Rice Intensification (SRI), which increases productivity by making use of certain types of soil and nutrients, enables farmers to produce more rice using less water.

More bad news for cereal lovers is that rice and wheat also have particularly high greenhouse gas (GHG) footprints. Flooded rice paddies, for instance, release significant amounts of methane, and as such contribute 1.5 percent of global GHG emissions. Fortunately, however, a study conducted in Korea found that implementing SRI practices reduced methane emissions by as much as 72.8 percent.

Global greenhouse gas footprint of various commodities. Oxfam

Comparing the carbon emissions of various crops. Oxfam