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Aug 26, 2023

Cities are the first line of defense in humanity’s battle against deadly heat. Bloomberg Green’s Hot Cities series looks at changes some of the world’s hottest cities are making to protect their people from extreme temperatures.

By Mohammad Tayseer and Laura MillanPhotographs by Annie Sakkab

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Cities are the first line of defense in humanity’s battle against deadly heat. Bloomberg Green’s Hot Cities series looks at changes some of the world’s hottest cities are making to protect their people from extreme temperatures.

Driving through the industrial Marka neighborhood in the east of Jordan’s capital Amman, past motor shops and concrete buildings, the last thing you expect to find is a budding forest where wildflowers bloom in the spring.

Nestled between a refugee camp and an airport, this ecological oasis — slightly smaller than a tennis court — is home to heat-resistant trees that are almost seven feet tall. The native species, including Palestine buckthorn, spiny hawthorn and Atlantic pistachio, were specially chosen because they can survive in extremely arid landscapes and arranged so they can grow into a dense forest within decades.

The mini-forest is the brainchild of Deema Assaf, a 39-year old Jordanian architect, and her Japanese collaborator Nochi Motoharu, who have spent the last five years nurturing similar spaces across Amman. “Our project is about many things,” Assaf says as she walks around the young trees in Marka. “Making the heat more bearable, increasing the green cover, but more importantly, it is about restoring the endangered plant species that have been around for thousands and some for millions of years.”

This year is on course to be the warmest on record as heat readings from Tokyo to Phoenix reach new heights, triggering wildfires and an unprecedented melting of ice sheets in Antarctica. The Middle East, already home to some of the hottest cities on Earth, is warming twice as fast as the global average. Temperatures in some parts of Jordan, a country of about 11 million, approached 45C (113F) during a heat wave in August, the second one its citizens endured this year.

Sprawled over seven hills, Amman sits on a plateau more than 700 meters (2,300 feet) above sea level. That’s historically kept it cooler than other parts of the country, but the city’s arid climate makes it particularly vulnerable to global warming. Projections show that temperatures above 45C will become common in Jordan by mid-century, with scientists finding that this level of warming would have been extremely rare or impossible without human-induced climate change.

Jordan, which had heat wave warnings in July and August, is planting more trees to tackle roasting temperatures

To help people find relief from the heat, Assaf and Nochi have scoured Amman for leftover urban spaces that can be turned into shade-giving forests. They’ve developed five so far, once even utilizing a piece of land that used to be a dumping ground. In the fall, they’ll embark on their sixth and largest project yet that will be spread over 1,000 square meters. Their work is funded by the German Federal Ministry for Economic Cooperation and Development and is implemented in partnership with the local government.

Planting trees can save lives when extreme heat strikes. A research paper published earlier this year in The Lancet found that increasing tree cover in some European cities could have prevented 40% of the 6,700 heat-related deaths that occurred in the summer of 2015. The Middle East has been left out of most research into how trees impact the urban climate, but studies from Europe, China and the US consistently show that areas covered by trees are cooler than those that are not — sometimes by as much as 12C on extremely hot days.

While the trees in Amman’s mini-forests are still young — the oldest has only been around for four and a half years — there’s a perceptible cooling effect of about 14C under their canopies compared with open areas, Assaf says. “There’s certainly a difference,” she says.

Cultivating a forest from scratch in Amman’s hot and dry climate requires some horticultural trickery.

That’s why Assaf and Nochi employ a method developed by Japanese botanist Akira Miyawaki in the 1970s. The Miyawaki approach involves densely packing indigenous trees close together. This fuels intense competition among the saplings for sunlight and soil nutrients, triggering rapid growth. In some cases, a forest can emerge in as little as ten years.

The method was developed in the middle of Japan's industrial boom, following World War II, when many of the country's forests and green areas were disappearing. Miyawaki laid out his process in a 1999 paper published in Plant Biotechnology. After identifying the ideal types of trees to grow, he planted two to three seedlings per square meter. He then covered the ground with a mulch of organic materials such as rice straw to prevent soil erosion and lock in moisture. The close proximity of the trees and natural interactions between the species meant the plants only needed to be irrigated for two to three years and there was no need for insecticides or herbicides. “The site basically becomes maintenance free,” Miyawaki wrote. “Natural management is the best management.”

Miyawaki’s approach became popular in the late 20th century and was replicated in multiple locations, from Europe to Southeast Asia and South America. In Jordan, Assaf and Nochi’s biggest challenge was deciding which trees to plant. Miyawaki was able to conduct field surveys of Japan’s forests, but many of Jordan’s forests were destroyed over the last few decades and native knowledge of its trees was lost as urban development took precedence over preserving its ecology.

The duo spent months piecing together information from historical accounts about which plants were more likely to thrive in Jordan’s geography without human intervention. That led them to revive some of Jordan’s endangered species, including the evergreen and deciduous oak, wild pistachio, turpentine tree, wild pear, hawthorns and eastern strawberry.

To the delight of residents in Marka, their new mini-forest has also lured different types of birds, butterflies, bugs, and even small animals such as the fennec fox, fostering a larger ecosystem that otherwise would never have developed there. The neighborhood now has “more breeze at night,” says Sami Hajj, the 53-year-old owner of a local supermarket, and the view is nicer from the rooftops.

Hajj has noticed the heat rising in Amman. “Ten years ago, we never needed air conditioners, nowadays we use them quite often,” he says. He can hear the units humming from almost every house all day long in the summer. “I worked and lived in Saudi Arabia for years,” Hajj says. “Now Amman feels as hot as Saudi Arabia in the summer.”

More intense and frequent heat waves have been punishing for people in Jordan, even those who are accustomed to hot weather growing up in a country that’s almost 75% desert and with barely 1% of forest cover.

Many people now stay indoors through most of the summer and don’t allow their children to play outside in the scorching heat. “This makes the kids annoyed,” says Tareq Quzaa, a 45-year-old father of three who lives near the mini-forest in Marka. “But what to do? There is no option but to stay home when it’s very hot.”

Assaf’s mini-forest campaign is a small part of Jordan’s wider efforts to adapt to a warmer planet, which include a push to green rooftops using plants grown indoors and painting some old buildings with heat-reflecting white paint. The government has set aside 2.5 million Jordanian Dinar ($3.5 million) over the next three years to support the planting of 10 million trees across the country by the end of the decade.

It’s not just about preparing for more heat. “We are witnessing an increase in heat waves and flash floods which destroyed many businesses and infrastructure over the past years,” says Mohammad Khashashneh, secretary-general at Jordan’s Ministry of Environment. “The erratic rainfall is dangerous.”

Flash floods that hit Amman in May killed at least one person, flooded tunnels and damaged parts of the old town. Tourists had to be evacuated from the ancient rock city of Petra in December after massive rainfall flooded the 2000-year-old archaeological attraction. Assaf says her mini-forests can help fight the floods by acting “as a sponge” to soak up water.

But Jordan will need many, many more trees to have a real impact. “Such little forests here and there across the city will not have a major impact on reducing the rising heat as Amman is mostly concrete buildings and blocks,” says Omar Shoshan, president of the Jordan Environmental Union, a group of some of the country’s most prominent green organizations.

He’s also skeptical the government will succeed in planting 10 million trees by 2030. Aside from needing financing to maintain the trees and protect them from disruptions such as wildfires, the major challenge will be securing water supplies to irrigate them, he says.

To address the problem, Khashashneh says Amman’s government has started building 7,500 water-harvesting systems in schools, mosques and state-owned buildings to collect rainwater. Greywater from bathroom sinks, showers and washing machines is also being treated and reused to keep more trees alive.

While one solution is to create more low-maintenance Miyawaki forests, the approach does come with its own risks. They may lack complex ecosystems compared with natural forests that have organically matured over a few centuries, says Shubhendu Sharma, an industrial engineer who studied with Miyawaki and now runs Afforestt, a company which plants mini-forests in India.

Still, “the complexity increases with time,” Sharma says, adding that the multi-layered forests grown using Miyawaki’s method make better wind barriers and are less prone to wildfires. “Because these forests block the wind, the fire will not be able to burn with same intensity.”

Assaf is well aware that her mini-forests aren’t going to save Jordan from the coming heat. When her latest project is complete, all the trees she’s planted will only cover 2,000 square meters of Amman, less than 0.5% of the city’s total land area.

But Assaf hopes her project helps inspire more action to preserve green spaces. Nature has a way of restoring balance, but it’s the human race that’s the weakest and most vulnerable link in this chain, she says. “I hope people get in touch with the native ecology and understand it and appreciate it and go back to nature,” Assaf says. “And hopefully we do so before it is too late.“

Assaf first learned about man-made forests and indigenous plants while working as an architect. It was a trip with Nochi to attend a workshop by Afforestt in Rajasthan — another desert — that spurred her to replicate the idea back home.

Assaf and Nochi started work on a pilot project in 2018 — a modest 107-square-meter backyard lawn on someone’s private property. Funded by the homeowner, the pair worked for days preparing the soil and planting the seedlings. The trees, now two to four meters high, were the first baby Miyawaki forest in the Arab world.

Every additional forest since has been a welcome respite for those living near it — and even those who don’t. People have thronged to the Marka baby forest in hordes since it opened to the public, with some driving up to 30 minutes to get there.

“The only escape in the neighborhood is this park that is much greener than others,” says Quzaa, who has seen sales at his grocery store across from the forest shoot up during weekends. “People from other areas come to enjoy a cool breeze.”

Visual media produced in partnership with Outrider FoundationPhoto Editing by Jody Megson