(CNN)Almost 5 billion people could struggle with water shortages by 2050 due to climate change, according to the United Nations.
Already, more than 25% of the world's crops are grown in regions with severe water shortages, according to the World Resources Institute.
In many countries, farmers tap into groundwater to irrigate their crops, particularly during periods of limited rainfall, and experts warn that irrigation is contributing to water shortages in drought-prone regions.
Here, we look at five everyday water-intensive foods that are using precious water in areas where it is in short supply.
Almonds from California
Aabout 80% of the world's almonds are grown in California. A recent study found that between 2004 and 2015, it took an average of 12 liters of water to grow just one Californian almond, and almond farmers rely heavily on irrigation and groundwater reserves to water their crops.
Almond production uses around 2 trillion liters of water per year and is contributing heavily to groundwater depletion and land degradation, according to Professor Yoshihide Wada, deputy director of the water program at the International Institute for Applied Systems Analysis.
Groundwater levels in the Central Valley, where most almond crops are grown, dropped by almost a half-meter annually during California's historic seven-year drought in 2011, according to a study by Cornell University.
"It is unsustainable," Wada said, adding that almond prices could rise if farmers keep pumping deeper to reach groundwater. "It's economically unprofitable if you go too deep."
Many almond farmers are taking steps to cut water use, for example by using micro-irrigation systems, which apply water directly to tree roots.
The Almond Board of California says that by 2025, the California almond community commits to reduce the amount of water used to grow a pound of almonds by an additional 20%.
Avocados from Petorca, Chile
It takes an average 2,000 liters of water, 10 full bathtubs, to grow just one kg of avocados, according to the Water Footprint Network, a Dutch organization that advocates for better management of water resources.
The brunch favorite's water consumption is four times the amount needed to produce the same amount of oranges or a kilogram of tomatoe