More trees, less asphalt: How Portugal’s cities can beat the heat

As Portugal endures another spell of extreme temperatures, experts are warning that the country’s cities need more trees, parks and permeable surfaces – and less asphalt – if they are to remain liveable in a warming climate.

Just one day after Lisbon recorded highs of 58.3°C on asphalt pavement in sun, renewing the debate about how cities can be kept ‘cooler’, Teresa Calix, an urban architecture specialist and lecturer at the Faculty of Architecture of the University of Porto, has defended that introducing more green spaces and natural elements into urban areas is one of the most effective ways of reducing temperatures and tackling the “urban heat islands” where heat becomes trapped.

“Renaturalising our cities wherever possible, using nature-based solutions, is fundamental to cooling urban spaces,” she told Lusa news agency.

Traditionally, cities have been built using rigid, impermeable materials that absorb and retain heat. Replacing some of these surfaces with parks, gardens and trees can help lower temperatures while also improving rainwater absorption and reducing flooding risks.

“Asphalt is very good at reducing noise, but it’s terrible when it comes to heat,” Calix said, noting that it stores heat throughout the day and releases it slowly overnight, preventing cities from cooling down.

She argues that adapting cities to climate change often means reversing planning decisions made during the last century.

“It’s about doing, in many cases, the opposite of what we did throughout the previous century,” she said.

Learning from other cities

Calix points to several international examples of successful urban regeneration projects.

In Seoul, the Cheonggyecheon stream was uncovered after an elevated motorway was removed, creating one of the city’s best-known public spaces.

She also highlights Madrid Río, where sections of motorway were transformed into riverside parks, and New York’s High Line, the elevated railway converted into a linear park that combines public space with extensive planting.

Another increasingly popular approach is reopening rivers and streams that were buried beneath cities decades ago, helping reduce temperatures while creating more attractive public spaces.

Portugal ‘moving too slowly’

While Portugal has begun embracing greener urban planning, Calix believes progress remains slow.

“I think we’re moving forward very slowly because, in many cases, we already know which solutions work best, but we don’t always choose them,” she said.

She highlighted Porto’s ongoing programme to plant trees on every street where conditions allow, the inclusion of environmental performance criteria in the city’s municipal master plan and the creation of new green spaces such as Parque da Asprela and Parque da Alameda de Cartes.

The car dilemma

One of the biggest obstacles, she argues, is Portugal’s heavy reliance on private cars.

Roads and parking occupy vast areas of urban space that could otherwise be used for trees, green corridors or wider pavements, while the lack of robust public transport makes reducing car use politically and socially difficult.

The biggest challenge will be finding the right balance between space for cars and space that cannot continue to belong to cars, she said.

Calix believes cities will increasingly have to strike compromises between transport, environmental protection and quality of life as they adapt to a changing climate.

“Basically, every subject related to the way we have to work with cities in the 21st century requires compromise and balance, which is sometimes difficult (to achieve). We will never find the best solution for everything,” she acknowledged.

Source: LUSA