Informing people about the health risks linked to climate change is twice as likely to spur public support for government-led climate action than messages focused on economic or environmental impacts, an international study has found.
Based on a survey of around 30,000 respondents in Brazil, India, Japan and South Africa carried out in late 2025, the report published this month by the Climate Opinion Research Exchange (CORE) and the Wellcome Trust reveals strong public support for climate action.
Over 80% of respondents said they are concerned about the impacts from climate change, the survey shows. A majority also back government measures to prevent public health impacts associated with the climate crisis.
“Humanitarian emergencies” are already increasing around the world due to human-caused rising temperatures, according to the World Health Organization (WHO). More than a third of the global population is exposed to climate threats like wildfires, extreme heatwaves, and tropical storms and floods, it says. These threats are amplified by human-caused greenhouse gas emissions.
Dustin Gilbreath, a researcher at CORE and one of the study’s lead authors, said that communicating these risks to the general public can be an effective way to inspire climate action, given that health is a basic concern for everyone across the political spectrum.
“If you suddenly find out that climate change is hurting your health and your children’s health, more people are rightfully more open to that argument,” he said. “At the end of the day, we all care about our health, regardless of our political inclinations.”
At COP28 in Dubai, more than 150 countries issued a declaration “expressing grave concern” over climate-fuelled health impacts, and pledged to strengthen policies that can cut carbon emissions and benefit people’s health in the process – for example by reducing air pollution from cars or factories.
More than 80 nations also endorsed a plan to improve the health sector’s resilience to climate impacts at the COP30 summit in Belém last year. The initiative received $300 million in philanthropic backing to help governments identify health risks, improve monitoring of climate threats, and strengthen emergency responses to extreme weather events, among other measures.
Despite these pledges, health has not been at the top of the agenda at key meetings like the recent conference on Transitioning Away from Fossil Fuels in Santa Marta, Colombia. The Global Climate and Health Alliance, which represents 250 health organisations, said leaders in Santa Marta “did not address the importance of protecting people’s health”.
Health priorities vary by country
To gain insights into people’s attitudes towards climate change, researchers tested 16 different messages with respondents in a survey-based randomised trial, comparing their reactions to messages on health-related issues like extreme heat or infectious diseases, and non-health issues related to jobs, the cost of living or nature. They also compared the participants’ reactions to a control group in each country who were not shown any messages.
While a majority were concerned about the health impacts from climate change, the types of effects that caused the strongest reaction varied depending on the country.
In South Africa, for example, public opinion resonated very strongly with messages related to children’s health. Messages linked to food and water insecurity also chimed well with South Africans, who recognised widely that climate change is a threat to people’s health.
The study’s authors say that context is key to understanding the effectiveness of messaging. South Africa, for example, has a young population with a median age of 28 years – compared to Europe’s 45 years – and has faced severe water shortages in cities like Cape Town, which was close to a “Day Zero” event after a major drought between 2016 and 2018. This term refers to the threat of municipal services running out of water.
Brazilians, on the other hand, reacted strongly to messages related to mental health impacts, which performed better than other messages by a wide margin. These types of impacts include, for example, severe anxiety or stress caused by losses after a flood or hurricane. In total, 93% of Brazilians said they are somewhat, or very concerned about, climate change.
Neha Dewan, senior advisor at the Wellcome Trust, a health-focused charitable foundation, said this finding was “counter-intuitive”, given that mental health is often seen as less of a priority. “This really helps us see what’s unexpected and find newer ways of reaching different audiences,” she added.
In Japan, extreme heat was the top-performing message, while in India it was air pollution and access to healthcare. Dewan said the India results confirm what people already discuss informally. “Every time I’m back home seeing family in India, everybody talks about air pollution. It’s the living, breathing reality.”
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Commission urges government action
Dewan said she hoped the findings “go beyond journals” and instead can “actually end up in society”, with the goal of helping “empower policy conversations”. Respondents across countries firmly supported government action to prevent or protect them from the health impacts of a warming climate.
In Brazil and South Africa, emissions-cutting measures such as building solar capacity to produce clean energy had more than 90% support, while in India and Japan respondents strongly backed adaptation measures like investments in allowing air-conditioned public buildings to be used during heatwaves.
Ahead of the May 18-22 World Health Assembly, the WHO’s highest decision-making body, experts highlighted the urgency of implementing such steps. The Pan-European Commission on Climate and Health, composed of former global leaders and chaired by former Icelandic Prime Minister Katrín Jakobsdóttir, called on governments “to take forward climate action that delivers benefits for human health”.
The commission issued a 17-point plan to address health impacts from the climate crisis, which includes declaring climate change a “global health emergency” and bringing it to the agenda of national security councils, as well as scaling up “climate-health investment”.
“The climate crisis is a threat to our safety and security, social cohesion, human rights and health,” Jakobsdóttir said in a statement. “Climate action is not merely a necessity. It is a high-return investment for a more just and resilient society.”
The Wellcome Trust’s Dewan said the survey provides data-backed insights showing policymakers that the public supports stronger action on climate change. “It’s beyond anecdotal now. Here’s the evidence telling us that constituents really care about these issues,” she said.
Fresh approach to climate dialogue
The findings of the study suggest that a focus on health could become an effective way for policymakers and activists to draw in new audiences and inspire action on climate change, the authors of the report said.
“The cost-of-living message or the jobs and economy messages have been used over and over again. People have been saying this for a good decade. Probably the people that are convinced by this already would’ve said they’re concerned about climate change,” said Gilbreath of CORE.
He added that the health angle is probably a newer approach for some audiences, but the hypothesis based on the survey findings would need to be tested with further research. He also noted that economic messages still serve a purpose in some contexts and should not be abandoned.
Dewan said health messaging could become a “missing piece” in climate communications. “Health is personal, proximal, relevant and – politically speaking – it’s depolarising,” she said.
“It gives us an inroad to talk about climate differently in a way that feels very relevant,” she explained. “It’s about figuring out what’s the next insight to unpack and make these communications and engagements even stronger and relevant.”
