Hot date: Will this tough desert fruit win the race with climate change?

For most of us, dates are an occasional sweet treat – a long-lasting, caramel-flavored addition to lunchboxes, scones, hiking kits and pantries.

But in the Middle East and North Africa (MENA), the dried fruit’s meaning and significance are much more expansive. The date palm (Phoenix dactylifera L.) evolved there and is the oldest and most abundant fruit tree in the region.

Today, it makes up a key component of MENA’s agri-food systems and an integral part of local cultural heritage and social and economic life.

The United Arab Emirates (U.A.E.), for instance, has more than 40 million date palm trees – more than any country in the world – and exports over USD 221 million in dates each year.

Emiratis also traditionally use the tree’s trunk for building homes and weave its fronds, leaves and fibers into traditional handicrafts. Some varieties also feature in traditional Muslim medicine.

To survive in their hot, arid homelands, date palm trees are resilient by design. They can handle very high temperatures, thrive in sand rather than soil, and cope with very little water.

“It’s one of the most important crops [in the region] because it is well adapted to heat and produces a lot of energy: it is rich in nutrients and also in carbohydrates,” says Augusto Berrera, chief scientist at the International Centre for Biosaline Agriculture (ICBA).

“And for the amount of energy produced by plant per liter of water, it’s probably one of the most efficient ones in this region.”

But the crop still uses significant amounts of the region’s precious freshwater: date palm irrigation makes up about a third of the U.A.E.’s total groundwater use. And as the country’s population grows, and the climate crisis makes conditions in the region even more extreme, its limited freshwater reserves – mostly from underground aquifers – are becoming depleted, and sea level rise is making many of them salty.

Adapting to water scarcity

However, that’s not necessarily a death knell for date production, as a long-running field experiment has shown. In 2001, at their U.A.E.-based experiment station, ICBA planted 18 varieties of date palm in a three-hectare plantation.

Since then, it has subjected the trees to a number of tests to ascertain and find ways to enhance their resilience to salinity, heat and pests.

“Traditionally, dates were irrigated with very high-quality water, and plenty of it, but the success of ICBA’s research has been to demonstrate that they can actually be irrigated with quite salty water – about half the concentration of salinity that you find in seawater,” says Berrera.

“And it doesn’t compromise the quality of the product: on the contrary, it seems to actually increase the sugar content of some of the varieties.”

The researchers have also developed sensors to ensure the palms are watered as minimally as possible, successfully applied water retention agents to soil to further reduce water use, and developed high-tech responses to the red palm weevil, a devastating pest afflicting palm trees.

Additionally, they’ve experimented with treating date palm with arbuscular mycorrhiza (AM), a symbiosis between plants and members of an ancient phylum of fungi that improves the supply of water and nutrients to the host plant. AM has the potential to enhance the salinity and drought tolerance of plants.

As the researchers discovered, mycorrhiza can benefit date palm trees during the early growth stage under marginal conditions. Date palms grow better under natural conditions when effectively associated with AM fungi, and they require less chemical fertilizer and inputs when effectively mycorrhized.

Diversity is key

Overall, the research has shown that dates can be grown with just a third of the freshwater that was previously being used. This frees up millions of liters to grow other crops that are important for diversifying the food basket and also improving nutrition and food security.

It’s especially crucial to keep multiple varieties of date palm alive and in circulation, as is happening at the ICBA plantation, because the palms are propagated from tissue, not seed, so all of those within a variety are clones of each other.

“That means that if one variety turns out to be vulnerable to climate change impacts, they all go down,” says Berrera. “People talk about water and soil, but also equally important is the capacity to adapt and to understand how much breeding has limited the natural variation of plants and, in doing so, the capacity for them to survive.”

And as global leaders prepare to descend on the U.A.E. for the 28th UN Climate Change Conference (COP28) in November, it’s critical that such diversity and adaptability also be present in the voices heard and solutions shared there.

“Climate change has stressed the need for thinking more outside the box,” says Berrera.