Evidence of the increasingly severe health impacts of climate change increases public concern and support for government action across Brazil, India, Japan and South Africa according to a major study conducted for Wellcome by the Climate Opinion Research Exchange (CORE).

Public concern around climate change and support for climate action shifts people’s attitudes twice as often when people are informed about climate change’s impacts on their health, compared to when they receive other information about climate risks.

The influence of climate change on extreme heat, food and water, and children’s health prompt the greatest levels of public concern across the four countries.

The study found differences between countries in how people perceive risks to health from climate change:

• In Brazil, the public are highly concerned about the mental health impacts of climate change, as well as about the impact on food and water insecurity. In all, 79% of the public reported they want the government to take more action on climate change, with 82% wanting urgent action to prevent climate impacts on public health.
• In India, air pollution and access to healthcare as a result of climate impacts drive public concern. 66% of the public want the government to do more on climate change, while 74% want urgent action to safeguard against climate impacts on health.
• In Japan, extreme heat is the most important issue for the public, alongside air pollution, infectious diseases and the risks of climate change to the health of older people. 67% of the public said they want the government to do more on climate change, with 58% believing that urgent action on climate and health should be undertaken.
• In South Africa, climate impacts on children’s health carry the most weight with the public, as well as food and water shortages, and maternal health. An overwhelming 85% of the South African public want the government to take action on climate change, and 82% want specific action to prevent climate impacts on health.

The findings of the research, based on a randomised control trial of over 30,000 respondents across the four countries between September and October 2025, demonstrate widespread concern among the public about the health risks of climate change, and the extent to which these concerns are driving demand for stronger policies.

"The data is clear - when the public finds out how the climate is harming our health, they want the government to do more,” said Dustin Gilbreath, lead researcher of the survey and Senior Analyst at CORE.

“The data shows most of the public are already concerned about climate change and believe the government should take urgent action to prevent climate change from harming public health."

“As the global climate crisis accelerates, its devastating impacts on health are intensifying, making climate change one of the most acute threats to human health,” said Dr Jeni Miller, Executive Director of the Global Climate and Health Alliance.

“As a result of the insufficient action in the face of this challenge, it has become a fully-fledged global health crisis - a reality which resonates strongly with the public. Governments have an obligation to act now to protect the health and wellbeing of their populations by cutting climate warming emissions, and ensuring that people are protected from the worst impacts of climate change.”

“This study gives us a timely opportunity - health-framed messages are not just relevant, they are twice as effective at shifting public attitudes and policy support. That matters because the climate crisis is a health crisis, and people around the world are increasingly concerned by it. We must now ensure support for credible and deliverable solutions based on global evidence so that decision-makers take action to improve health and save lives - now and in the future.” said Neha Dewan, Senior Advisor at the Wellcome Trust.

The severe impacts of climate change, caused mostly by burning fossil fuels, on human health are well documented.The 2025 Lancet Countdown Report on Health and Climate Change highlights the damage caused to the health of people across the world: from extreme heat and extreme weather events to drought and ever more pervasive infectious diseases, the climate crisis is affecting every aspect of people’s lives and overwhelming healthcare systems.

The survey also shows that greater awareness of these health impacts increases public support for specific policies in each country, including investment in renewable energy, promotion of electric vehicles and financial support for more climate-vulnerable countries and emerging economies to transition to clean energy.

The study by CORE comes amid growing international attention to the risks to health from climate change, with the launch of the Belem Health Action Plan and the Climate Health Funders Coalition at last year’s COP30 in Belém, Brazil.