Sicker Planet, Sicker People: Environmental breakdown is eroding the foundations of human health

For decades, we’ve been told “we need to save the planet”. But the truth is, the planet will be fine. Over billions of years it’s weathered asteroid impacts, ice ages, and mass extinctions at a scale we can hardly imagine.

What’s at stake now is something far more fragile: us.

That’s the message at the heart of a new Lancet article which argues that as the climate warms and ecosystems falter, we are no longer facing a purely environmental crisis, but a full-scale public health emergency. 

The landmark study synthesises decades of scientific data to show how transgressing the nine planetary boundaries - which range from climate and biodiversity to pollution and freshwater - is already inflicting widespread harm on human health and is likely to drive a growing share of global disease in coming decades.

Land degradation and biodiversity loss are fuelling outbreaks of malaria, dengue, and other zoonotic diseases. Chemical and plastic pollution is driving developmental delays, hormonal disruption, and soaring rates of anxiety and depression. Rising temperatures are linked to pregnancy complications, kidney failure, and mortality spikes.

Ten days of extreme heat killed 2,305 people in a sample of 12 European cities last month. A recent analysis suggests that a single five-day heatwave in India could result in as many as 30,000 excess deaths.

This is the human face of the planetary crisis. Environmental breakdown is no longer altering only forests, coastlines, and deserts. It is disrupting the very foundations of human health and wellbeing: our bodies.

And yet, even now, we discuss planetary boundaries in impersonal abstract terms, parts per million of CO₂, functional species diversity, and nitrogen flow. These numbers matter of course, but they can conceal as much as they reveal.

The true costs of planetary breakdown are not found in charts. They are found in neonatal units and cancer registries, in stolen potential, and in the quiet grief of families facing wholly preventable illnesses and deaths.

Predictably, those least responsible suffer most: children, indigenous peoples, low-income communities, and those yet to be born.

Recognising that human and planetary health are inseparable should not just sharpen our sense of urgency, it must fundamentally reshape how we govern, invest, and lead.

Exactly ten years ago the Rockefeller Foundation, on whose board I now sit, supported the launch of the Planetary Health Alliance and a report published in The Lancet, an attempt to connect the dots between ecological breakdown and human wellbeing. Now, through the Planetary Guardians, we’re pushing to turn that knowledge into action.

Yet a decade on, despite everything we know, policymakers and business leaders remain wedded to outdated yardsticks. GDP growth and quarterly earnings reports dominate decision-making.

Using these metrics alone to chart 21st-century progress is like assessing national wellbeing by the miles of railway laid. Once a useful proxy, now totally incoherent. Meanwhile, most leaders lack a consistent framework for assessing ecological collapse or the human costs of rampant chemical pollution.

What is needed now is not marginal reform, but a wholesale upgrade to the operating system of modern leadership.

On a practical level, that begins with better metrics. Interest rates or earnings per share tell us little about whether we are securing the foundations of long-term wellbeing. We must track the integrity of ecosystems, the resilience of food and water systems, and the mental health of our populations.

We also require better tools that empower policymakers and business leaders to make decisions that link environmental risk with public health, social outcomes, and economic trajectories.

Tackling food insecurity demands attention to soil microbiomes and biodiversity. Securing supply chains means factoring in watershed stability and extreme heat. Ensuring robust economic fundamentals involves counting the real costs of pollution-induced illness.

The good news is that we already know what works.

Decarbonising our energy systems not only cuts emissions but reduces the air pollution that claims millions of lives each year.

Restoring nature can improve physical and mental health, enhance food security and nutrition, cool cities, and help buffer against the impacts of extreme weather.

And when we invest in people, by making it easier for households to adopt clean technologies, restore local ecosystems, or shift toward more sustainable diets and land use, we unlock a cascade of benefits: lower bills, stronger communities, and more equitable health outcomes.

This isn’t feel-good theory. It’s practical policy. The problem is that our institutions are still built for yesterday’s problems, and the piecemeal interventions of the past are no longer enough.

And time is short. The authors warn that we have perhaps one generation, twenty to thirty years, to reverse course. That is a perilously narrow window in which to reorient how we live, produce, and govern.

Doing so will require institutional architecture capable of bridging the gap between environmental science and public health and wellbeing. The authors’ proposed “planetary health dashboard” is one such innovation, an effort to monitor the state of both natural systems and human health with the same rigour applied to inflation or bond yields.

It’s a smart idea, and long overdue. But let’s not be naïve, no dashboard, however precise, can substitute for true leadership underpinned by moral courage.

For the last 150 years, we have been dismantling the very foundations of prosperity and doing so in the name of prosperity itself. There was a time where we could feign ignorance, but that time has long passed.

The science is clear. The risks are measurable. The costs are already being paid in hospital admissions, in economic disruption, and in the slow erosion of public trust.

What remains in doubt is not the data, but whether those in power are prepared to govern in accordance with the world as it is, not as it once was.

In the end, the defining failure of this era may not be ignorance, but the refusal to act on what we know.