Zero Emissions Day
September 21
About Zero Emissions Day
Zero Emissions Day, also known as ZeDay, is observed each year on 21 September. In 2026 it falls on Monday 21 September, the same date as the United Nations International Day of Peace. The initiative calls on individuals, businesses and governments to take a voluntary one-day break from burning fossil fuels, with the founding ambition of giving the planet at least one day of rest from greenhouse gas emissions each year.
When is Zero Emissions Day?
| Year | Date | Day |
|---|---|---|
| 2025 | 21 September | Sunday |
| 2026 | 21 September | Monday |
| 2027 | 21 September | Tuesday |
| 2028 | 21 September | Thursday |
The date is fixed at 21 September every year. For background and resources, see the official initiative page at the Climate Leadership Coalition.
Who runs Zero Emissions Day and why it exists
Zero Emissions Day was created in 2008 by Canadian artist and environmental activist Ken Wallace, based in Nova Scotia. Wallace launched the idea as a global call to action at zeroemissionsday.org, arguing that a single collective day without fossil fuel burning could demonstrate what a zero-carbon future might look and feel like, and build momentum for the systemic changes needed to get there. The concept has since grown into a global movement with participation in over 100 countries by 2020, supported by environmental organisations, universities and sustainability networks worldwide.
The core message remains the same as in 2008: “Giving our planet a day off a year.” ZeDay does not claim that 24 hours without emissions will solve the climate crisis; rather, it frames the date as an annual checkpoint for individuals and organisations to reset, measure their impact and recommit to reducing emissions year-round.
Why it matters: the climate picture in 2026
The scientific backdrop to ZeDay grows more pressing each year. According to the Intergovernmental Panel on Climate Change (IPCC), human activities have already caused approximately 1.0°C of warming above pre-industrial levels, with the rate of change accelerating. The World Health Organization projects that climate-related factors, including heat stress, malnutrition, malaria and flooding, could cause an additional 250,000 deaths globally per year from 2030 onwards.
In the UK, the Climate Change Act 2008 set a legally binding target to reduce greenhouse gas emissions by 80% by 2050, later strengthened in 2019 to a net zero target. Despite significant progress, the UK’s independent Climate Change Committee has consistently noted that policy implementation is falling short of the pace required.
How to take part
Zero Emissions Day encourages practical, measurable action rather than symbolic gestures. Ways to participate on 21 September include:
- Leaving the car at home and travelling by bicycle, foot or public transport for all journeys during the day.
- Switching off non-essential electrical appliances and avoiding high-energy activities such as tumble drying or running dishwashers at high temperatures.
- Eating a plant-based diet for the day, since food production accounts for roughly a quarter of global greenhouse gas emissions.
- Offsetting unavoidable emissions, for instance by donating to verified reforestation or renewable energy projects.
- Using the date to review home or workplace energy use and set a concrete emissions-reduction target for the coming year.
- Sharing the day on social media with #ZeroEmissionsDay or #ZeDay to encourage others.
How organisations mark the day
Schools, universities and workplaces across the UK and internationally use 21 September as a hook for sustainability campaigns. Common approaches include car-free days, cycle-to-work or cycle-to-school schemes, lunchtime events on climate action, and pledges to switch to renewable energy contracts. Some local councils and business improvement districts organise community clean-ups or tree-planting events to coincide with the date.
The Campaign for Greener Arbitrations, the Climate Leadership Coalition and a range of environmental NGOs mark the day with webinars, pledges and social media campaigns. Because ZeDay falls on the same date as the UN International Day of Peace, some organisations combine the two themes, highlighting the link between climate change and global security.
Official resources
- Zero Emissions Day at Climate Leadership Coalition (official)
- IPCC Special Report on Global Warming of 1.5°C
- UK Climate Change Committee
Related dates
- International Day of Peace (21 September)
- World Environment Day (5 June)
- Earth Day (22 April)
- Browse all September awareness days and Environment and Sustainability days
Last reviewed: 7 September 2026.
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