The largest gains would be expected in China and India (Representational)
India and China could gain massive health benefits by tackling climate change, the WHO said on Wednesday. For India, the gains could be $3.28-8.4 trillion.
Meeting the goals of the 2015 Paris Climate Change Agreement could save about a million lives a year worldwide by 2050 through reductions in air pollution alone.
The latest estimates from leading experts also indicate that the value of health gains from climate action would be approximately double the cost of mitigation policies at global level, and the benefit-to-cost ratio is even higher in countries such as China and India.
The World Health Organization (WHO) report was launched at the UN Climate Change Conference (COP24) in this Polish city.
It highlights why health considerations are critical to the advancement of climate action and outlines key recommendations for policy makers.
The largest gains would be expected in China and India, which would generate even larger net benefits by pursuing the 1.5 degrees Celsius target rather than the two degrees target ($0.27-2.31 trillion in China and $3.28-8.4 trillion in India).
The health gains of meeting the two degrees target would also significantly offset the costs in other regions, such as the European Union (seven-84 per cent) and the US (10-41 per cent).
Exposure to air pollution causes seven million deaths worldwide every year and costs an estimated $5.11 trillion in welfare losses globally.
In the 15 countries that emit the most greenhouse gas emissions, the health impacts of air pollution are estimated to cost more than four per cent of their GDP. Actions to meet the Paris goals would cost around one per cent of the global GDP.
"The Paris Agreement is potentially the strongest health agreement of this century," WHO Director-General Tedros Adhanom Ghebreyesus said.
"The evidence is clear that climate change is already having a serious impact on human lives and health. It threatens the basic elements we all need for good health -- clean air, safe drinking water, nutritious food supply and safe shelter -- and will undermine decades of progress in global health. We can't afford to delay action any further."
The same human activities that are destabilising the earth's climate also contribute directly to poor health. The main driver of climate change is fossil fuel combustion which is also a major contributor to air pollution.
"The true cost of climate change is felt in our hospitals and in our lungs. The health burden of polluting energy sources is now so high that moving to cleaner and more sustainable choices for energy supply, transport and food systems effectively pays for itself," WHO Director of Public Health, Environmental and Social Determinants of Health Maria Neira said.
Switching to low-carbon energy sources will not only improve air quality but provide additional opportunities for immediate health benefits.
For example, introducing active transport options such as cycling will help increase physical activity that can help prevent diseases like diabetes, cancer and heart disease.