Cooling Down Earth’s Cities

With recent record-breaking summer heat waves, spiking urban temperatures have become a major concern for cities tackling climate change. Densely populated areas are warming far faster than their rural and suburban surroundings, creating dangerous “urban heat islands” that threaten public health, increase energy consumption, and disproportionately impact city dwellers with lower incomes.

Meanwhile, designing buildings to protect occupants from climate extremes—while managing energy demand—has become increasingly complex, and especially challenging in the developing world.

“Closing the skills and capacity gap in those markets is one of the most important levers the sector has,” Hanane Hafraoui, GlobalABC lead program manager at the United Nations Environment Programme (UNEP), told The Earth & I.

Guest Lecture 'Cooler and Fairer Cities: Heat Mitigation, Adaptation and Inclusive Urban Greening

 

Heatwaves spark interest in Gulf-style extreme cooling (Interview in Financial Times)

At sunrise, before Dubai’s megamalls open their doors to the general public, people are already bounding along marbled corridors past the luxury boutiques that forged the city’s reputation as a shoppers’ paradise. But these are not customers looking for bargains: the emirate’s cavernous shopping centres double as air-conditioned running tracks during the summer, with runners gathering at 6am to escape outside temperatures approaching 40C and compete in races of up to 10km. 

The race to cool buildings with less electricity

America's answer to hotter summers has overwhelmingly been more air conditioning, and engineers are now looking for ways to keep people cool without driving up electricity demand.

Why it matters: The need for cooling is surging. The issue isn't just how to generate more electricity — it's how to use less of it and ease demand when grids are most strained.

Interview to Discover Magazine

I recently had the pleasure of being interviewed by Discover Magazine about the growing impact of air conditioning on cities, its implications for energy use and urban heat, and the exciting opportunities offered by innovative passive cooling technologies. We discussed how sustainable cooling solutions can help create more resilient, comfortable, and climate-responsive urban environments. Many thanks to Discover Magazine for the invitation and for highlighting this important topic.

An Environmental Crisis: Urban Overheating with Professor Matthaios Santamouris

 

Our cities are becoming heat traps. Every year, streets, rooftops and buildings trap more heat, pushing temperatures higher, making extreme heat one of the fastest growing threats to urban life today.

Professor Matthaios Santamouris has spent his career developing the technologies and strategies helping cities survive rising temperatures. His work confronts a critical question:

Can our cities survive the heat they’ve created?

Heat-Proofing Cities Becomes Mandatory Amid Global Heatwaves by Joe Ennis

When I wrote this article, I was very much thinking of Australian cities. Or those in the Middle East. But we're now seeing persistent highs above 30 degrees in Ireland. 45 in France. In Germany, the Rhine is running dry and everywhere heat-related deaths are soaring. Heat-proofing our cities is not optional anymore. With thanks to Professor Mat Santamouris AM and Jessica Holz CPEng RPEQ. 

Richard Francis-Jones and fjcstudio Interview

I would like to express my sincere appreciation to Richard Francis-Jones and fjcstudio for the invitation. It is an honour to be part of this event and to contribute to the ongoing dialogue on creating cooler, healthier, and more resilient cities.

In a Warming World, Air Conditioning Is a Necessary Evil. Or Is it?

As carbon emissions push Earth’s average temperature to new heights and usher in unprecedented heat waves, humanity’s reliance on air conditioning is growing. The trouble is, AC consumes massive amounts of energy and—due to the world’s continued reliance on fossil fuels—emits lots of carbon.

Overcoming this feedback loop presents a significant engineering challenge that is becoming increasingly urgent as the world warms. Enter passive cooling: non-mechanical approaches to lowering indoor temperatures.

2026 Newly Elected Members of World Academy of Art and Science

In July, WAAS announced the results of its 2026 elections. Six new Trustees were elected, while two Trustees were re-elected. The Academy also elected 25 new Fellows and six new Associate Fellows, and re-elected one Associate Fellow and seven Junior Fellows.

Air conditioning is not enough to keep people cool — can scientists find an alternative?

 

As large swathes of Europe and Asia swelter through record heatwaves this summer, discussions have centred around an obvious way to keep people cool: more air conditioners. Popular in high-income countries such as the United States, Japan and Australia, these units are less common in homes in Europe or in low-income countries. But air conditioners are expensive to run, use vast amounts of energy and generate heat, so installing them in every home that needs one is not the answer, say scientists. Instead, they say that, over the past few years, there have been advances in materials that passively cool buildings, offering a solution without the drawbacks.

Letter of the President of the Legislative Council

 

Air Conditioning Saves Lives. Scientists Think It Also Might Doom Us All.

 

One of the major reasons we find ourselves in this current climate crisis is because of a near-religious devotion to convenience. For more than a century, scientists have known that burning coal warms the planet, but the finite, energy-dense resource was too convenient a fuel to pass up. Some of the first cars to ever hit the road were clean electric cars, but cars with internal combustion engines were more convenient to mass produce. And so on.

As the planet continues to inch past the 1.5 ºC increase in global temperature—a threshold originally reported by the Intergovernmental Panel on Climate Change as critical to avoiding catastrophic climate impacts—this same dedication to convenience dominates the conversation

Διακοπές στα τσιμεντονήσια: Το φαινόμενο της αστικής θερμικής νησίδας και πώς το αποφεύγουμε

Για τον έναν στους δύο Έλληνες που δεν θα πάει διακοπές φέτος το καλοκαίρι, το φαινόμενο της αστικής θερμικής νησίδας φροντίζει να τον μεταφέρει νοερά σε τροπικές ζώνες, με άσφαλτο και τσιμέντο αντί για βλάστηση.

Πρόκειται για ένα φαινόμενο που το γνωρίζουμε πολύ καλά όσοι ζούμε σε πυκνοκατοικημένες περιοχές, ακόμα και αν δεν ξέρουμε πώς να το ονομάσουμε. Η αστική θερμική νησίδα

BUILD UP Expert Talk - Matthaios Santamouris

 

We can’t air-condition our way out of a hotter future, says UNSW expert

 A new global review argues passive cooling technology must become central to climate adaptation.

As temperatures rise around the world, air conditioning is saving lives. But a growing reliance on it is also placing unprecedented pressure on electricity grids, increasing greenhouse gas emissions and making cities even hotter.

A global review led by UNSW Sydney's Professor Mat Santamouris AM – an expert in innovative heat mitigation technologies and strategies for cities, opens in a new window – argues that keeping buildings cool without relying solely on air conditioning will be critical for adapting to climate change.

Cities cannot outrun hotter climates with air-con alone

Air-conditioning units flying off shelves worries Australian urban heat expert Mat Santamouris.

With 10 systems purchased every second worldwide, the University of NSW professor fears the cooling technology has become the default response to rising global temperatures.

"We cannot air-condition our way out of climate change," he said.

"If every building depends entirely on mechanical cooling, we create enormous pressure on electricity systems while adding even more heat to our cities."

Passive cooling for the built environment

Passive cooling technologies reduce heat and solar gains in buildings and public spaces while dissipating excess heat. This approach could reduce impacts of mechanical air conditioning, which has environmental impacts and consumes electricity, contributing to peak demand and grid stress. In this Review, we discuss advances in passive cooling technologies, focusing on smart solar control, ventilation, and radiative, evaporative and hybrid dissipation systems.

Keeping Cool: From Building Physics to Climate Resilience

RESEARCH PATHWAY: personal reflections on a career in research

Mat Santamouris (University of New South Wales) reflects on a research journey explaining how an early fascination with solar energy and building physics evolved into research on urban overheating, cool materials, and city-scale heat mitigation. The social imperative for research to address now is: Who is most exposed to extreme heat, and what can science do to protect them?

My research career evolved in close alignment with changing societal agendas to address energy scarcity, climate change, and thermal discomfort in buildings and cities. What began as an inquiry rooted in the physics of buildings and passive cooling strategies progressively expanded in scale, first to encompass urban microclimates and urban overheating, and later to the development of innovative materials and large-scale heat mitigation strategies aimed at protecting cities from extreme heat.

Throughout this trajectory, a consistent objective has been to translate scientific understanding into solutions that enhance thermal comfort, reduce energy demand, and promote environmental and social equity. At the same time, this process has not been without constraints: significant barriers frequently emerged in translating research into practice, including limited engagement frameworks with policymakers, institutional inertia, regulatory constraints, and the challenge of communicating complex scientific concepts to non-specialist audiences.

How cities are fighting back against the 'heat island effect'

As temperatures rise, researchers are rethinking how cities measure and respond to urban heat. But experts say successful solutions require finding solutions tailored to local conditions rather than relying on one-size-fits-all fixes.

Record-breaking heat and humidity are already upon us at the start of what is predicted to be a scorcher of a summer. 

Our cities, with their dark, asphalt surfaces, exhaust-emitting vehicles, and heat-trapping buildings, feel these temperatures the most. Many residents experience at least 8 degrees of additional heat just because of their neighborhood layout, according to Climate Central, which assessed heat patterns in 65 metropolitan areas.  

Συνέντευξη στο Ριζες Abroad - Ertflix

Watch here : https://www.ertflix.gr/#/details/ERT_PS058431_E0

Honorary Fellowship of the Royal Institute of British Architects

 

UCL: Cooling Our Cities? Recent Developments in Urban Heat Mitigation Technologies

 

Speaker: Professor Mat Santamouris AM Professor Mat Santamouris AM is a Distinguished Professor of High Performance Architecture at the University of New South Wales (UNSW), Sydney. He is a Member of the Order of Australia. He previously served as Professor at the University of Athens, Greece, and has held Visiting Professorships at ten leading institutions worldwide, including in the UK, Japan, Italy, Korea, Singapore, China, Cyprus, and Malaysia

Member of the Order of Australia

I am deeply honoured to have been named a Member of the Order of Australia by the Governor‑General, a recognition that humbles me and fills me with gratitude. This distinction reflects not only my own efforts but, more importantly, the unwavering support, insight, and dedication of the many collaborators, colleagues, and mentors who have walked alongside me throughout my career.

Honorary Fellow - The Royal Institute of British Architects

The Royal Institute of British Architects has conferred upon me the distinguished honour of being elected an Honorary Fellow. I regard this recognition with profound gratitude and deep humility. It is an exceptional distinction, reserved for a very small number of individuals worldwide, and I am sincerely moved to be counted among them.

Mitigating Urban Overheating Keynote

 

World Society of Sustainable Energy Technologies (WSSET) - Interview

 Why is climate action so slow when the evidence is conclusive? 

 Prof. Mat Santamouris explained that climate action moves at different speeds because countries have different priorities, and that the overall pace is shaped more by those in power than by the public.

 A simple example is political lobbying. Fossil fuel companies spend millions influencing governments and policy processes, which can delay stricter emissions rules or weaken climate targets. 

Deeply Honoured

I am deeply honoured and truly grateful to share that Northumbria University, Newcastle UK, has appointed me as a Visiting Professor.

This distinction carries great meaning for me, and I feel a profound sense of responsibility toward the University’s leadership for their trust and confidence.

I look forward to contributing with dedication, enthusiasm, and respect for the academic community that has welcomed me so warmly.

Addressing the Impact of Urban Overheating Using Advanced Heat Mitigation Technologies

 

Recognition plaque from the Ecole Nationale des Travaux Publics de l'Etat

I feel very proud, and I am deeply moved by the awarding of an honorary recognition plaque from the French Grande École nationale des Travaux publics de l'Etat in Lyon. I warmly thank all those who honored me, and I would like to dedicate this award to my unjustly lost friend and ENTPE professor, Gerard Guarraccino. We will always remember you, Gerard