Planting certain kinds of trees can make cities hotter at night, not cooler, according to a new study. Trees can significantly reduce the temperature of cities during the day by providing shade, changing the airflow and through the evaporation of water from microscopic pores in their leaves.
But a new study has found that tree canopies can trap heat, closing those pores in response to heat and drought stress, leading to higher temperatures at night. The research, published on Tuesday in peer review journal Communications Earth & Environment, found that urban trees can bring surface temperatures down by as much as 12°C. But that cooling ability is heavily dependent on the species, urban layout and climate.
In heavily built-up and dry cities like Dubai, trees cool the air more, Dr Ronita Bardhan, associate professor of Sustainable Built Environment at the University of Cambridge, told The National. They take the water in the air into their leaves through their pores, using it to perform photosynthesis, where they convert light into chemical energy.
"If you’re sweating and standing under a tree, the sweat is taken up by the air into the leaves and the leaves then use that to perform their photosynthesis function. That’s why you feel cooler," said Dr Bardhan. But at night, the microscopic pores in trees' leaves close. "Where it closes down, the heat below it is trapped. It is no longer able to escape."
In arid climates, air has less water, so trees take up less water. Whereas in a very humid area, even after the trees had taken a lot of humidity to do their evapotranspiration process, there is still water remaining, said Dr Bardhan. The study "busts the myth that trees are the ultimate panacea for overheating cities across the globe”, she added.
“Trees have a crucial role to play in cooling cities down but we need to plant them much more strategically to maximise the benefits which they can provide.”
In tropical wet and dry climates, trees cool cities in countries such as Nigeria by as much as 12°C during the day, but heat the area around them at night by up to 0.8°C. In arid climates, including the UAE, trees cooled cities by around 9°C in daytime, warming them at night by 0.4°C.
Ghaf trees – in pictures
In tropical, humid climates, the daytime cooling effect dropped to 2°C, with 0.8°C warming at night. In temperate climates, trees can cool cities by up to 6°C and warm them by 1.5°C. Urban environments are more likely to feature a variety of evergreen and deciduous trees of different sizes – a mix that tends to result in greater cooling in temperate, continental and tropical climates, according to the study.
Using a variety of trees in these climates generally results in 0.5°C more cooling than in cities which only have deciduous or evergreen trees. Researchers said this is because mixed trees can balance seasonal shading and sunlight, providing three-dimensional cooling at various heights.
However, in arid climates, evergreen species dominate and cool more effectively in cities like Cairo and Dubai. Popular evergreen species in the UAE include the national tree – the ghaf – scientific name prosopis cineraria – which typically lives for 120 years. It was traditionally used to feed livestock and was revered for its purported medicinal properties.
In open urban layouts, cooling can be improved by about 0.4°C because their larger green spaces allow for more and larger tree canopies and a greater mix of tree species, the study said.
“Our study provides context-specific greening guidelines for urban planners to more effectively harness tree cooling in the face of global warming,” Dr Ronita Bardhan said.
“Our results emphasise that urban planners not only need to give cities more green spaces, they need to plant the right mix of trees in optimal positions to maximise cooling benefits. Urban planners should plan for future warmer climates by choosing resilient species which will continue to thrive and maintain cooling benefits,” she added.
COMPANY PROFILE
Name: HyperSpace
Started: 2020
Founders: Alexander Heller, Rama Allen and Desi Gonzalez
Based: Dubai, UAE
Sector: Entertainment
Number of staff: 210
Investment raised: $75 million from investors including Galaxy Interactive, Riyadh Season, Sega Ventures and Apis Venture Partners
Key facilities
- Olympic-size swimming pool with a split bulkhead for multi-use configurations, including water polo and 50m/25m training lanes
- Premier League-standard football pitch
- 400m Olympic running track
- NBA-spec basketball court with auditorium
- 600-seat auditorium
- Spaces for historical and cultural exploration
- An elevated football field that doubles as a helipad
- Specialist robotics and science laboratories
- AR and VR-enabled learning centres
- Disruption Lab and Research Centre for developing entrepreneurial skills
In Full Flight: A Story of Africa and Atonement
John Heminway, Knopff
The specs: 2018 Dodge Durango SRT
Price, base / as tested: Dh259,000
Engine: 6.4-litre V8
Power: 475hp @ 6,000rpm
Torque: 640Nm @ 4,300rpm
Transmission: Eight-speed automatic
Fuel consumption, combined: 7.7L / 100km
UAE currency: the story behind the money in your pockets
More from Neighbourhood Watch:
WHEN TO GO:
September to November or March to May; this is when visitors are most likely to see what they’ve come for.
WHERE TO STAY:
Meghauli Serai, A Taj Safari - Chitwan National Park resort (tajhotels.com) is a one-hour drive from Bharatpur Airport with stays costing from Dh1,396 per night, including taxes and breakfast. Return airport transfers cost from Dh661.
HOW TO GET THERE:
Etihad Airways regularly flies from Abu Dhabi to Kathmandu from around Dh1,500 per person return, including taxes. Buddha Air (buddhaair.com) and Yeti Airlines (yetiairlines.com) fly from Kathmandu to Bharatpur several times a day from about Dh660 return and the flight takes just 20 minutes. Driving is possible but the roads are hilly which means it will take you five or six hours to travel 148 kilometres.
Emergency
Director: Kangana Ranaut
Stars: Kangana Ranaut, Anupam Kher, Shreyas Talpade, Milind Soman, Mahima Chaudhry
Rating: 2/5
Our legal consultant
Name: Hassan Mohsen Elhais
Position: legal consultant with Al Rowaad Advocates and Legal Consultants.
COMPANY PROFILE
Name: Kumulus Water
Started: 2021
Founders: Iheb Triki and Mohamed Ali Abid
Based: Tunisia
Sector: Water technology
Number of staff: 22
Investment raised: $4 million
More on animal trafficking
UAE SQUAD
Mohammed Naveed (captain), Rohan Mustafa, Ashfaq Ahmed, Rameez Shahzad, Shaiman Anwar, Mohammed Usman, Mohammed Boota, Zawar Farid, Ghulam Shabber, Ahmed Raza, Sultan Ahmed, Imran Haider, Qadeer Ahmed, Chirag Suri , Zahoor Khan
The burning issue
The internal combustion engine is facing a watershed moment – major manufacturer Volvo is to stop producing petroleum-powered vehicles by 2021 and countries in Europe, including the UK, have vowed to ban their sale before 2040. The National takes a look at the story of one of the most successful technologies of the last 100 years and how it has impacted life in the UAE.
Read part four: an affection for classic cars lives on
Read part three: the age of the electric vehicle begins
Read part one: how cars came to the UAE
SPECS
Toyota land Cruiser 2020 5.7L VXR
Engine: 5.7-litre V8
Transmission: eight-speed automatic
Power: 362hp
Torque: 530Nm
Price: Dh329,000 (base model 4.0L EXR Dh215,900)
The%20Genius%20of%20Their%20Age
%3Cp%3EAuthor%3A%20S%20Frederick%20Starr%3Cbr%3EPublisher%3A%20Oxford%20University%20Press%3Cbr%3EPages%3A%20290%3Cbr%3EAvailable%3A%20January%2024%3C%2Fp%3E%0A
How has net migration to UK changed?
The figure was broadly flat immediately before the Covid-19 pandemic, standing at 216,000 in the year to June 2018 and 224,000 in the year to June 2019.
It then dropped to an estimated 111,000 in the year to June 2020 when restrictions introduced during the pandemic limited travel and movement.
The total rose to 254,000 in the year to June 2021, followed by steep jumps to 634,000 in the year to June 2022 and 906,000 in the year to June 2023.
The latest available figure of 728,000 for the 12 months to June 2024 suggests levels are starting to decrease.
Director: Romany Saad
Starring: Mirfat Amin, Boumi Fouad and Tariq Al Ibyari
Moral education needed in a 'rapidly changing world'
Moral education lessons for young people is needed in a rapidly changing world, the head of the programme said.
Alanood Al Kaabi, head of programmes at the Education Affairs Office of the Crown Price Court - Abu Dhabi, said: "The Crown Price Court is fully behind this initiative and have already seen the curriculum succeed in empowering young people and providing them with the necessary tools to succeed in building the future of the nation at all levels.
"Moral education touches on every aspect and subject that children engage in.
"It is not just limited to science or maths but it is involved in all subjects and it is helping children to adapt to integral moral practises.
"The moral education programme has been designed to develop children holistically in a world being rapidly transformed by technology and globalisation."
Evacuations to France hit by controversy
- Over 500 Gazans have been evacuated to France since November 2023
- Evacuations were paused after a student already in France posted anti-Semitic content and was subsequently expelled to Qatar
- The Foreign Ministry launched a review to determine how authorities failed to detect the posts before her entry
- Artists and researchers fall under a programme called Pause that began in 2017
- It has benefited more than 700 people from 44 countries, including Syria, Turkey, Iran, and Sudan
- Since the start of the Gaza war, it has also included 45 Gazan beneficiaries
- Unlike students, they are allowed to bring their families to France
UAE currency: the story behind the money in your pockets
UAE v Gibraltar
What: International friendly
When: 7pm kick off
Where: Rugby Park, Dubai Sports City
Admission: Free
Online: The match will be broadcast live on Dubai Exiles’ Facebook page
UAE squad: Lucas Waddington (Dubai Exiles), Gio Fourie (Exiles), Craig Nutt (Abu Dhabi Harlequins), Phil Brady (Harlequins), Daniel Perry (Dubai Hurricanes), Esekaia Dranibota (Harlequins), Matt Mills (Exiles), Jaen Botes (Exiles), Kristian Stinson (Exiles), Murray Reason (Abu Dhabi Saracens), Dave Knight (Hurricanes), Ross Samson (Jebel Ali Dragons), DuRandt Gerber (Exiles), Saki Naisau (Dragons), Andrew Powell (Hurricanes), Emosi Vacanau (Harlequins), Niko Volavola (Dragons), Matt Richards (Dragons), Luke Stevenson (Harlequins), Josh Ives (Dubai Sports City Eagles), Sean Stevens (Saracens), Thinus Steyn (Exiles)
THE%20STRANGERS'%20CASE
%3Cp%3E%3Cstrong%3EDirector%3C%2Fstrong%3E%3A%20Brandt%20Andersen%3Cbr%3E%3Cstrong%3EStarring%3A%20%3C%2Fstrong%3EOmar%20Sy%2C%20Jason%20Beghe%2C%20Angeliki%20Papoulia%3Cbr%3E%3Cstrong%3ERating%3A%3C%2Fstrong%3E%204%2F5%3C%2Fp%3E%0A
More from Rashmee Roshan Lall
SHAITTAN
%3Cp%3E%3Cstrong%3EDirector%3A%20%3C%2Fstrong%3EVikas%20Bahl%3Cbr%3E%3Cstrong%3EStarring%3A%20%3C%2Fstrong%3EAjay%20Devgn%2C%20R.%20Madhavan%2C%20Jyothika%2C%20Janaki%20Bodiwala%3Cbr%3E%3Cstrong%3ERating%3A%20%3C%2Fstrong%3E3%2F5%3C%2Fp%3E%0A
Brief scores:
Toss: Sindhis, elected to field first
Kerala Knights 103-7 (10 ov)
Parnell 59 not out; Tambe 5-15
Sindhis 104-1 (7.4 ov)
Watson 50 not out, Devcich 49
The National's picks
4.35pm: Tilal Al Khalediah
5.10pm: Continous
5.45pm: Raging Torrent
6.20pm: West Acre
7pm: Flood Zone
7.40pm: Straight No Chaser
8.15pm: Romantic Warrior
8.50pm: Calandogan
9.30pm: Forever Young
AI traffic lights to ease congestion at seven points to Sheikh Zayed bin Sultan Street
The seven points are:
Shakhbout bin Sultan Street
Dhafeer Street
Hadbat Al Ghubainah Street (outbound)
Salama bint Butti Street
Al Dhafra Street
Rabdan Street
Umm Yifina Street exit (inbound)
Brief scoreline:
Wales 1
James 5'
Slovakia 0
Man of the Match: Dan James (Wales)
AIDA%20RETURNS
%3Cp%3E%3Cstrong%3EDirector%3A%20%3C%2Fstrong%3ECarol%20Mansour%3C%2Fp%3E%0A%3Cp%3E%3Cstrong%3EStarring%3A%20%3C%2Fstrong%3EAida%20Abboud%2C%20Carol%20Mansour%3C%2Fp%3E%0A%3Cp%3E%3Cstrong%3ERating%3A%3C%2Fstrong%3E%203.5.%2F5%3C%2Fp%3E%0A
SPECS
%3Cp%3E%3Cstrong%3EEngine%3A%20%3C%2Fstrong%3E2-litre%204-cylinder%20petrol%20(V%20Class)%3B%20electric%20motor%20with%2060kW%20or%2090kW%20powerpack%20(EQV)%0D%3Cbr%3E%3Cstrong%3EPower%3A%3C%2Fstrong%3E%20233hp%20(V%20Class%2C%20best%20option)%3B%20204hp%20(EQV%2C%20best%20option)%0D%3Cbr%3E%3Cstrong%3ETorque%3A%3C%2Fstrong%3E%20350Nm%20(V%20Class%2C%20best%20option)%3B%20TBA%20(EQV)%0D%3Cbr%3E%3Cstrong%3EOn%20sale%3A%20%3C%2Fstrong%3EMid-2024%0D%3Cbr%3E%3Cstrong%3EPrice%3A%20%3C%2Fstrong%3ETBA%0D%3C%2Fp%3E%0A
COMPANY%20PROFILE
%3Cp%3E%3Cstrong%3ECompany%20name%3A%3C%2Fstrong%3E%20Klipit%3C%2Fp%3E%0A%3Cp%3E%3Cstrong%3EStarted%3A%3C%2Fstrong%3E%202022%3C%2Fp%3E%0A%3Cp%3E%3Cstrong%3EFounders%3A%3C%2Fstrong%3E%20Venkat%20Reddy%2C%20Mohammed%20Al%20Bulooki%2C%20Bilal%20Merchant%2C%20Asif%20Ahmed%2C%20Ovais%20Merchant%3C%2Fp%3E%0A%3Cp%3E%3Cstrong%3EBased%3A%3C%2Fstrong%3E%20Dubai%2C%20UAE%3C%2Fp%3E%0A%3Cp%3E%3Cstrong%3EIndustry%3A%3C%2Fstrong%3E%20Digital%20receipts%2C%20finance%2C%20blockchain%3C%2Fp%3E%0A%3Cp%3E%3Cstrong%3EFunding%3A%3C%2Fstrong%3E%20%244%20million%3C%2Fp%3E%0A%3Cp%3E%3Cstrong%3EInvestors%3A%3C%2Fstrong%3E%20Privately%2Fself-funded%3C%2Fp%3E%0A
Company profile
Name: Steppi
Founders: Joe Franklin and Milos Savic
Launched: February 2020
Size: 10,000 users by the end of July and a goal of 200,000 users by the end of the year
Employees: Five
Based: Jumeirah Lakes Towers, Dubai
Financing stage: Two seed rounds – the first sourced from angel investors and the founders' personal savings
Second round raised Dh720,000 from silent investors in June this year
Result
Crystal Palace 0 Manchester City 2
Man City: Jesus (39), David Silva (41)
Conflict, drought, famine
Estimates of the number of deaths caused by the famine range from 400,000 to 1 million, according to a document prepared for the UK House of Lords in 2024.
It has been claimed that the policies of the Ethiopian government, which took control after deposing Emperor Haile Selassie in a military-led revolution in 1974, contributed to the scale of the famine.
Dr Miriam Bradley, senior lecturer in humanitarian studies at the University of Manchester, has argued that, by the early 1980s, “several government policies combined to cause, rather than prevent, a famine which lasted from 1983 to 1985. Mengistu’s government imposed Stalinist-model agricultural policies involving forced collectivisation and villagisation [relocation of communities into planned villages].
The West became aware of the catastrophe through a series of BBC News reports by journalist Michael Buerk in October 1984 describing a “biblical famine” and containing graphic images of thousands of people, including children, facing starvation.
Band Aid
Bob Geldof, singer with the Irish rock group The Boomtown Rats, formed Band Aid in response to the horrific images shown in the news broadcasts.
With Midge Ure of the band Ultravox, he wrote the hit charity single Do They Know it’s Christmas in December 1984, featuring a string of high-profile musicians.
Following the single’s success, the idea to stage a rock concert evolved.
Live Aid was a series of simultaneous concerts that took place at Wembley Stadium in London, John F Kennedy Stadium in Philadelphia, the US, and at various other venues across the world.
The combined event was broadcast to an estimated worldwide audience of 1.5 billion.
Ferrari 12Cilindri specs
Engine: naturally aspirated 6.5-liter V12
Power: 819hp
Torque: 678Nm at 7,250rpm
Price: From Dh1,700,000
Available: Now
The specs
Engine: 4.0-litre flat-six
Torque: 450Nm at 6,100rpm
Transmission: 7-speed PDK auto or 6-speed manual
Fuel economy, combined: 13.8L/100km
On sale: Available to order now
Secret Pigeon Service: Operation Colomba, Resistance and the Struggle to Liberate Europe
Gordon Corera, Harper Collins
Match info
UAE v Bolivia, Friday, 6.25pm, Maktoum bin Rashid Stadium, Dubai
PROFILE OF HALAN
Started: November 2017
Founders: Mounir Nakhla, Ahmed Mohsen and Mohamed Aboulnaga
Based: Cairo, Egypt
Sector: transport and logistics
Size: 150 employees
Investment: approximately $8 million
Investors include: Singapore’s Battery Road Digital Holdings, Egypt’s Algebra Ventures, Uber co-founder and former CTO Oscar Salazar
Gully Boy
Director: Zoya Akhtar
Producer: Excel Entertainment & Tiger Baby
Cast: Ranveer Singh, Alia Bhatt, Kalki Koechlin, Siddhant Chaturvedi
Rating: 4/5 stars
England's all-time record goalscorers:
Wayne Rooney 53
Bobby Charlton 49
Gary Lineker 48
Jimmy Greaves 44
Michael Owen 40
Tom Finney 30
Nat Lofthouse 30
Alan Shearer 30
Viv Woodward 29
Frank Lampard 29
Labour dispute
The insured employee may still file an ILOE claim even if a labour dispute is ongoing post termination, but the insurer may suspend or reject payment, until the courts resolve the dispute, especially if the reason for termination is contested. The outcome of the labour court proceedings can directly affect eligibility.
- Abdullah Ishnaneh, Partner, BSA Law
Jigra
Starring: Alia Bhatt, Vedang Raina, Manoj Pahwa, Harsh Singh
MATCH INFO
Manchester City 6 Huddersfield Town 1
Man City: Agüero (25', 35', 75'), Jesus (31'), Silva (48'), Kongolo (84' og)
Huddersfield: Stankovic (43')
How to protect yourself when air quality drops
Install an air filter in your home.
Close your windows and turn on the AC.
Shower or bath after being outside.
Wear a face mask.
Stay indoors when conditions are particularly poor.
If driving, turn your engine off when stationary.
Defending champions
World Series: South Africa
Women’s World Series: Australia
Gulf Men’s League: Dubai Exiles
Gulf Men’s Social: Mediclinic Barrelhouse Warriors
Gulf Vets: Jebel Ali Dragons Veterans
Gulf Women: Dubai Sports City Eagles
Gulf Under 19: British School Al Khubairat
Gulf Under 19 Girls: Dubai Exiles
UAE National Schools: Al Safa School
International Invitational: Speranza 22
International Vets: Joining Jack
