Our sustenance tied to planetary health

April 7 marked WHO's annual World Health Day, which this year has the theme "Our planet, our health." The future health of the planet and human health are inextricably linked. An estimated 13 million deaths annually are attributable to avoidable environmental causes, and that number will continue to grow unless overconsumption and reliance on fossil fuels are curbed, The Lancet said in its latest edition. Coming amid the Covid-19 pandemic, global economic disquiet, and war in Europe, this World Health Day was a timely and necessary reminder that global crises are entwined with climate change, and that we should not lose sight of the existential threat that ecological degradation poses to planetary and human health.

The Sixth Assessment Report by Working Group II of the Intergovernmental Panel on Climate Change, published recently, documents the wide-ranging negative impacts that environmental change is having on human health and wellbeing, and how these health risks will multiply if the internationally agreed goals to limit climate change are not met. Global heating is leading to more frequent and extreme weather events, such as heat waves, wildfires, floods, and storms – which endanger lives, harm mental health, spread disease, and wreak damage to people's livelihoods and the wider economy. More frequent extreme events in the future, and continuing climate change, will contribute to the burden of air pollution, to water and food insecurity, and undernutrition. Health systems must help both in efforts to limit global warming and in building population resilience to environmental changes that are already occurring, experts urge.

Public health has an important role in securing a sustainable future, and the potential co-benefits and cost-savings between sustainability and health are well documented. Active transport interventions, for example, can increase physical activity levels and mental wellness, while also reducing air pollution, energy consumption, and greenhouse gas emissions. Helping food producers and consumers to transition towards more sustainable diets can reduce risks of cardiovascular disease and unhealthy weight, while lessening land and water use, and greenhouse gas emissions.

However, there are many barriers to meeting the twin goals of universal health coverage and the transition to a sustainable society, including lack of political will to invest in prevention, and inequalities in power, wealth, and access. The Covid-19 pandemic has devastatingly exposed the weaknesses and inequalities in our health and humanitarian systems in the face of global crises. The world needs equitable investment in research, surveillance, and preventive health. The destabilising effects of climate change are falling most heavily on the most vulnerable.

Our window to limit global warming to the 1.5°C ambition agreed in the Paris Climate Agreement, and therefore reducing the impacts of climate change on societies and health, is rapidly closing. In the wake of the Covid-19 pandemic and the war in Ukraine, some political leaders have called for intensification of fossil fuel extraction. Given the, now clear, evidence for the destabilising potential of climate change for health and society, such suggestions should be recognised as self-defeating. Instead of regressing, these global crises should be the catalyst for rapid transitions to sustainable societies that focus on achieving good health and wellbeing for all people and the planet.