Global defences against universal transboundary threats to health, like climate change, air pollution and antimicrobial resistance, depend on WHO’s role as a guardian of public health. This role involves tracking rapidly evolving threats, quantifying the harm to health, and sounding the alarm. WHO also works to raise political awareness and extend advice on the best protective strategies for safeguarding public health. In these – as in many other areas – protective strategies require collaboration with multiple non-health sectors.

Climate change: a climate treaty is also a health treaty

Climate change is the defining issue for the 21st century. Climate variables affect the air people breathe, the water they drink, the food they eat, and even where they are able to live. Extreme weather events are becoming the norm and records are constantly being broken, with the past three years ranking as the hottest since records began.

For infectious diseases, climate change is a threat multiplier. It takes existing threats – whether from a cholera outbreak, the spread of Zika to new geographical areas, or the severe malnutrition that accompanies drought – and enhances them. The risks are familiar but their impact is amplified in frequency and severity. A changing climate can expand the distribution of infectious diseases, especially those transmitted by mosquitoes and other vectors, and invite the emergence of others. The emergence of Nipah virus and Hanta virus as human pathogens has been traced to extreme weather events that forced animal hosts to leave their ecological niches and invade human settlements.

Paris Agreement on Climate Change

In the historic 2015 Paris Agreement on Climate Change, countries made important commitments to cut greenhouse gas emissions and scale up adaptation to climate change. But more needs to be done. As many have noted, the world is recklessly late in agreeing to take action.

The stakes are high. WHO estimates that climate change is already causing tens of thousands of deaths every year. These deaths arise from more frequent epidemics of diseases like cholera, the vastly expanded geographical distribution of diseases like dengue, and deaths that follow extreme weather events, like heatwaves and floods.

Experts predict that, by 2030, climate change will be causing an additional 250 000 deaths each year from malaria, diarrhoeal disease, heat stress and undernutrition alone. The heaviest burden will fall on children, women and the poor, widening already unacceptable gaps in health outcomes.

The health sector has critical evidence, and persuasive arguments, to compel actions that can limit the adverse consequences of climate change. The Paris agreement is not just a treaty for saving the planet from severe, pervasive, and irreversible damage. It is also a significant public health treaty, with a huge potential to save lives worldwide.

If commitments are supported by actions on a sufficient scale, efforts to combat climate change will produce an environment with cleaner air, more abundant and safer freshwater and food, and healthier populations. Existing strategies that work well to combat climate change also bring important health gains. Investments in low-carbon development, clean renewable energy, and greater climate resilience are investments in better health.

Implementing and enforcing higher standards for vehicle emissions and engine efficiency can reduce emissions of short-lived climate pollutants, like black carbon and methane. Doing so could save around 2.4 million lives a year by 2030 and reduce global warming by about half a degree Celsius by 2050.

Researchers have estimated that reform of global energy subsidies could reduce carbon dioxide emissions by more than 20%, cut premature air pollution deaths by more than half, and raise government revenues by nearly $3 trillion. Measures such as early-warning systems for heatwaves and the protection of water, sanitation, and hygiene services against floods and droughts strengthen the resilience of health systems to withstand the shocks of climate change. Doing so safeguards recent progress against climate-sensitive diseases.

UN Framework Convention on Climate Change

In 2015, WHO, in collaboration with the secretariat of the UN Framework Convention on Climate Change and other partners, launched the first set of climate change and health country profiles. The aim is to empower ministers of health and other decision-makers to include health in climate negotiations. Profiles provide a snapshot of up-to-date information about current and future impacts of climate change on human health, and current policy responses in individual countries. They also illustrate, within the country context, the health benefits that arise from actions to mitigate climate change, like shifting to cleaner energy sources, using public transport, and promoting walking and cycling.

Minimizing adverse effects on public health has been part of the Framework Convention on Climate Change’s objectives since the first agreement in 1992. However, further efforts are needed to fully exploit the opportunity to protect the planet’s most valuable resource, its people. A ruined planet cannot sustain human lives in good health.