By Thin Lei Win

ROME, Sept 30 (Thomson Reuters Foundation) - The drought-hardy African morama bean, which tastes like cashew nuts when roasted, and the artichoke-flavoured buds of the Middle East's thorny akkoub plant may be foods of the future.

They are among two of the more than 7,000 edible plants that could thrive in a hotter world, nourishing millions of people, said a new report from Britain's Royal Botanic Gardens, Kew, coinciding with a United Nations meeting on reversing biodiversity loss.

An international team of researchers warned that more than half of the global population relies on just three crops — rice, maize and wheat — as staple foods, making diets highly vulnerable to the impacts of global warming.

"Climate change is threatening to unleash weather conditions, pests, and diseases that our current crops will struggle to cope with," the report said. "If humanity is to thrive in future, we need to make our food production systems more diverse, resilient, and environmentally sustainable."

A collaboration among 210 scientists from 42 countries, the report on the state of the world's plants and fungi identified their potential for medicine, food, and fuel.

But it warned that nearly 40% of all plants face extinction due to factors such as land clearing, over-harvesting of wild species, and changing weather patterns.

Tiziana Ulian, lead author of the food chapter and a senior scientist at Kew, told the Thomson Reuters Foundation humanity faces "a double challenge."

"On one hand, there is a problem of hunger in the world. On the other, there is a problem of excess of calories that leaves a lot of people obese," she said.

Diversifying the crops people grow and eat is key to tackling both issues as the planet heats up, she added.

In 2019, more than 3 billion people — about 2 in 5 — could not afford healthy diets and almost 690 million went to bed hungry, figures from the UN showed.

Yet many plants described as "neglected" are rich in nutrients, resistant to pests and diseases, and can grow even in difficult conditions, the report said.

For example, pandanus — a small-trunked tree which grows in coastal lowlands from Hawaii to the Philippines — could withstand drought, strong winds, and salt spray.

Morama beans also yield oil, butter, and milk, and its tuber and young stems are high in protein, while fonio, a grain-yielding grass species that grows wild across the savannas of West Africa, is high in iron, calcium, and several amino acids.

But realising their potential is a challenge because in industrialised food systems, growing, processing, and packaging are "geared towards uniformity," focused on very specific crops, said Danny Hunter, co-author of the food chapter.

One way to support a more diverse diet is through Brazil's national policy which stipulates that at least 30% of food for school meals must come from local farmers, he noted.

Hunter, a senior scientist at agricultural research group Bioversity International, said his organisation was working in Brazil, Turkey, Kenya, and Sri Lanka to promote native species.

At the same time, surging demand for healthy foods that suddenly become popular in Western societies can come at the expense of Indigenous communities and small farmers who have nurtured and managed them for generations, he said.

"When these things become 'superfoods,' these custodians don't really benefit — so we need to look at ways to empower them and work with them," he added.

(Reporting By Thin Lei Win @thinink, editing by Megan Rowling. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers the lives of people around the world who struggle to live freely or fairly. Visit http://news.trust.org)