From healthier homes to cleaner air: why planetary health matters now

Professor Ian Hamilton has joined The George Institute for Global Health as Program Director, Planetary Health, and Chair in Planetary Health at Imperial College London. His ambition is to connect research, communities and policy to address a defining question: how can we improve human health while protecting the natural systems on which it depends?

Long before Professor Ian Hamilton began studying the links between climate change and health, he experienced the power of the natural world at close range.

As a university student, Ian worked as a forest firefighter in Northwest Ontario, Canada. The job took him into communities threatened by wildfires and taught him two lessons that have stayed with him: nature can be an immense and unpredictable force, and environmental change is ultimately experienced by people.

“You go into communities trying to help protect what they have, while knowing there are moments when you cannot change the force of nature,” Ian says. “That stays with you.”

Today, Ian is an internationally recognised expert at the intersection of climate change, energy and health. He is the Working Group Mitigation Co-Chair for the Lancet Countdown on Health and Climate Change, a global collaboration that brings together hundreds of researchers to track the effects of climate change on health and inform policy responses.

His work ranges from global indicators and international reports to questions grounded in everyday life.

“What does it feel like to live in a cold home, or a very hot home?” he asks. “What does air pollution mean for children living near busy roads? What does climate action mean for communities already facing climate risk?”

These questions are at the heart of planetary health: understanding how human health depends on the health of their environment and the place they live, and finding solutions that protect both.

Looking beyond the health system

Ian’s particular expertise lies in the built environment: the homes, streets, workplaces, transport systems and communities in which people spend their lives. His research has examined building performance, indoor environmental quality, energy policy and the health effects of heat, cold and air pollution. He has also advised international initiatives concerned with sustainable buildings and access to clean energy.

“When someone presents to the health system with a problem, I often think: what happens when they walk out the door?” he says. “What kind of home, street, workplace or community are they returning to? Those settings matter enormously for health.”

This perspective helps make the benefits of climate action immediate and tangible. Improving housing can protect people from dangerous heat and cold. Cleaner transport can reduce air pollution around schools. More sustainable food systems can support healthier diets while reducing pressures on land, water and biodiversity.

“When we talk only in emissions, environmental or economic terms, we can miss the message that matters most to people: this can improve health now,” Ian says.

The challenge is increasingly urgent. The 2025 Lancet Countdown report found that climate change is claiming lives and damaging health worldwide, while the environmental conditions on which human life depends are becoming less stable.

Yet Ian’s central message is one of possibility: better decisions can produce cleaner air, healthier homes, safer communities and a more stable climate.

Putting equity at the centre

Ian believes those decisions must also be fair.

“If we are talking about change and transformation to protect people and place, we have to ask: does it protect those who need the most protection?”

Climate and environmental threats do not affect everyone equally. People already facing poverty, discrimination, poor housing or limited access to healthcare are often more exposed and have fewer resources with which to respond.

Ian’s work has therefore expanded to consider gender, energy access and historic injustice. In collaborative research in Mumbai, for example, the aim is not to arrive with a predetermined answer, but to work with communities to understand and help frame the changes they want to see.

For Ian, this requires researchers to acknowledge the limits of their own knowledge, bring different forms of expertise together and ensure that communities have a meaningful voice.

An opportunity to turn evidence into action

It was The George Institute’s strength in moving research beyond discovery and into practice that attracted Ian to his new role.

“There is such strong experience here in field trials, translating evidence into policy, working with communities and creating real-world impact,” he says. “That ability to turn evidence into action was very important to me.”

Planetary health already intersects with work across the Institute, including cardiovascular and brain health, food systems, health systems, digital technology and implementation science. Ian sees an opportunity to connect these areas, strengthen partnerships and turn promising ideas into research and practical solutions that can be tested and scaled.

“People across The George Institute are already helping to save lives,” he says. “The question is: can we do that in a way that is least harmful and most beneficial to the planet around us?”

Answering that question will require long-term partnerships and investment in interdisciplinary research — particularly the early work needed to bring researchers and communities together, generate evidence and translate it into policy.

For Ian, that is where philanthropy can be catalytic: enabling ambitious ideas to take shape, helping build collaborations across countries and disciplines, and supporting solutions until they are ready to attract larger-scale investment.

“The problems are connected, so our response must be connected too,” Ian says. “We can solve them one piece at a time, and many pieces together.”