New Zealand is set to mark its Earth Overshoot Day today (30 April 2025), three months earlier than the global average of 30 July. The latest Briefing from the Public Health Communication Centre explains how we can achieve a more ecologically sustainable society that also supports improved public health.

Earth Overshoot Day signals the moment when our demand for ecological resources exceeds what Earth can regenerate in a year, highlighting the urgent need for a shift towards more sustainable practices. If everyone lived like New Zealanders, we would need almost three Earths.

In contrast, countries like Uruguay are showing that a different path is possible. Their overshoot day is not projected until 17 December, demonstrating that it is possible for even high-income countries to live within their ecological footprint.

"Earth Overshoot Day is a powerful wake-up call," says University of Otago Public Health Professor Michael Baker. "Although it simplifies complex environmental systems, it helps communicate just how urgently we need to change course, for the sake of our environment, our economy and our health."

The Briefing points to countries like Uruguay, which show that strong environmental policies, widespread renewable energy adoption, sustainable agriculture, and compact, low-carbon cities can make a real difference.

Prof Baker says there are several ways NZ can reduce its ecological footprint.

• Boost renewable energy investments and transition to cleaner energy across transport, industry, and homes.
• Accelerate sustainable transport by investing in public transport, cycling infrastructure, and more compact urban design.
• Promote sustainable agriculture with regenerative practices, native reforestation, and local food systems to reduce waste and improve resilience.
• Encourage sustainable consumption, including a shift to healthier plant-based diets, reduced consumption and sustainable lifestyles by citizens and whanau/families.
• Embed sustainability in policymaking, ensuring that environmental conservation and resource management are core to decision-making.

While Earth Overshoot Day provides a clear signal of unsustainability, it does not capture all aspects of environmental health, such as biodiversity loss or pollution beyond CO2 emissions. Experts emphasise the importance of using a range of tools, including the Sustainable Development Goals and Earth system boundaries, to guide effective policy.

"This is not just an environmental issue, it’s a public health and economic opportunity," says Professor Ralph Chapman, an environmental economist with Victoria University.

"By acting now to reduce our ecological footprint, we can improve wellbeing, build resilience, and help ensure a better future for all New Zealanders."

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