On 31 March 2007, Sydney became the first city to switch off its lights for Earth Hour, sending a message to a climate-skeptic government that people cared about the planet. More than 2.2 million individuals participated in that symbolic act of unity. By the following year, Earth Hour had expanded to 50 million participants across 35 countries, with iconic landmarks such as the Golden Gate Bridge and the Colosseum plunging into darkness.

It was a striking visual reminder of the collective power of people. The event continued to grow exponentially, evolving from a simple switch-off campaign into the world’s largest grassroots movement for environmental action.

What Is Earth Hour?

Earth Hour, organized by the World Wide Fund for Nature (WWF) is a global commitment to environmental preservation. It encourages individuals, households, businesses, and governments to turn off non-essential lights for one hour, fostering awareness and inspiring action against climate change and biodiversity loss. Since its inception, it has influenced policy changes, driven conservation efforts, and mobilized millions to advocate for a more sustainable world.

Held annually toward the end of March, Earth Hour is strategically timed to coincide with the equinox, ensuring that night falls at a similar time across different time zones, creating a powerful global visual impact.

More than just an hour

While turning off lights remains the most visible expression of Earth Hour, its impact extends far beyond those 60 minutes. In 2010, three months after the United Nations COP15 Climate Conference in Copenhagen — a summit widely seen as a setback in climate negotiations — Earth Hour became a global call for renewed environmental action.

In French Polynesia, public pressure sparked by Earth Hour led to a historic environmental milestone: 5 million square kilometers of its exclusive economic zone in the South Pacific were designated as a Managed Marine Area, ensuring the protection of vital marine ecosystems for future generations.

The movement adapted and thrived even during the COVID-19 pandemic. With much of the world in lockdown, Earth Hour 2020 became a fully digital campaign, proving that environmental advocacy could transcend physical barriers. That year, supporters from 192 countries united online, and the first-ever Earth Hour Virtual Spotlight gained global traction, amplified by figures like Sofia Vergara, UEFA, and the United Nations.

A call for action

For over a decade, Earth Hour has united people worldwide in the fight against climate change. It has helped drive major commitments to carbon reduction, renewables, and conservation initiatives. However, while climate change remains an urgent crisis, Earth Hour has expanded its focus to address another pressing issue — the alarming loss of biodiversity.

Nature is not just an ally in combating climate change; it is essential for human survival. Forests regulate the climate, oceans provide oxygen, and biodiversity supports food security. Earth Hour seeks to ignite global conversations on the importance of protecting nature — not just for the planet’s sake, but for the health, happiness, and prosperity of future generations.

The most recent Earth Hour saw participation from more than 180 countries and territories. The campaign introduced the “Hour Bank,” where individuals pledged their time toward sustainability efforts. Over 1.4 million hours were collectively contributed, demonstrating that Earth Hour is no longer just about turning off the lights.

This unprecedented success was made possible through global partnerships, including Earth Hour’s first international corporate collaboration with Epson, which promoted energy-saving solutions.

As Earth Hour 2025 approaches, the call to action remains the same: switch off, speak up, and take steps — big or small — to protect the only home we have.