Earth Hour is a global event organized by the World Wildlife Fund (WWF). It happens every year, encouraging people, communities, and businesses to spend one hour helping the Earth. During this time, landmarks and businesses turn off lights that are not needed for one hour, from 8:30 to 9:30 p.m., usually on the last Saturday of March. This action shows support for the planet. The event began in Sydney, New South Wales, Australia, in 2007.

Sometimes, when Holy Saturday falls on the last Saturday of March, such as in 2024, Earth Hour is held one week earlier.

History of Earth Hour

In 2004, after seeing scientific research, WWF Australia worked with advertising company Leo Burnett Sydney to "discuss ideas for helping Australians learn about climate change." The idea of a large group turning off lights was created in 2006 and first called "The Big Flick." WWF Australia shared their plan with Fairfax Media, who, along with Sydney's mayor, Clover Moore, agreed to support the event. The first Earth Hour took place in Sydney, Australia on March 31, 2007, at 7:30 p.m. local time.

In October 2007, San Francisco held its own "Lights Out" event inspired by Sydney's Earth Hour. After their event, organizers supported Earth Hour again in March 2008.

Earth Hour 2008 happened worldwide on March 29, 2008, from 8 p.m. to 9 p.m. local time, marking the first anniversary of the event. Thirty-five countries had official cities, and over 400 cities joined. Many landmarks turned off non-essential lights, and some websites, like Google, darkened their homepages.

A survey showed 36 million Americans, or about 16% of adults, took part in Earth Hour 2008. The survey also found a 4% increase in interest in environmental issues after the event.

Tel Aviv held Earth Hour on March 27, 2008, to avoid conflicting with the Sabbath. Dublin moved their event to 9 p.m. to 10 p.m. because of their location near the north.

In Bangkok, Thailand, electricity use dropped by 73.34 megawatts, which equals 41.6 tonnes of carbon dioxide saved. Another report said 165 megawatt-hours and 102 tonnes of carbon dioxide were saved. This was less than a similar event in May 2007, when 530 megawatt-hours and 143 tonnes were saved.

In the Philippines, power use dropped by 78.63 megawatts in Metro Manila and up to 102.2 megawatts on Luzon. The biggest drop in Metro Manila was 39 megawatts at 8:14 p.m., and 116 megawatts in Luzon at 8:34 p.m.

Ontario, Canada, used 900 megawatt-hours less electricity during Earth Hour. In Toronto, electricity use dropped by 8.7% compared to a typical March Saturday night.

In Ireland, electricity use dropped by 1.5% for the evening. Between 6:30 p.m. and 9:30 p.m., 50 megawatts were saved, equal to 150 megawatt-hours or about 60 tonnes of carbon dioxide.

In Dubai, turning off lights on major landmarks and dimming streetlights saved 100 megawatt-hours of electricity, a 2.4% drop in demand.

The best result was in Christchurch, New Zealand, where electricity demand dropped by 13%. However, the national grid operator reported that overall electricity use in New Zealand was 335 megawatts during Earth Hour, slightly higher than the average of the previous two Saturdays. In Sydney, Australia, electricity use dropped by 8.4%, less than the 10.2% drop in 2007. In Calgary, Canada, electricity use actually increased by 3.6% during Earth Hour. Cold weather in Calgary contributed to higher use, and later years showed little change in electricity use.

Earth Hour 2009 took place from 8:30 p.m. to 9:30 p.m. local time on March 28, 2009. The event was called "Vote Earth" and aimed to collect one billion votes worldwide, timed with the 2009 United Nations Climate Change Conference. WWF reported that 88 countries and 4,159 cities participated, ten times more cities than in 2008.

For the first time, the United Nations Headquarters in New York City joined. In Egypt, the Sphinx and the Great Pyramids of Giza turned off their lights. In the Philippines, 647 cities and towns participated, with over 10 million Filipinos joining. Greece had 484 cities, and Australia had 309.

Although WWF said the event is not about saving electricity, some cities reported savings to show participation. In Ontario, excluding Toronto, electricity use dropped by 6%, and Toronto saw a 15.1% drop. In the Philippines, 611 megawatt-hours of electricity were saved, equal to shutting down a dozen coal-fired power plants for an hour.

In Sweden, electricity use dropped by 2.1% between 8 p.m. and 9 p.m., and 5% in the next hour. This saved enough electricity for about half a million households. In Vietnam, electricity demand dropped by 140 megawatt-hours during Earth Hour 2009.

Earth Hour 2010 was held from 8:30 p.m. to 9:30 p.m. local time on March 27. In Israel, the event took place on April 22. One hundred twenty-six countries participated. In the United States, about 90 million people turned off lights, including landmarks like Mount Rushmore, the Las Vegas Strip, the Empire State Building, and Niagara Falls.

Some cities made long-term changes. In Chicago, guidelines were created to reduce light pollution and carbon emissions. Mount Rushmore in South Dakota turned off lights earlier each night. In Vietnam, electricity use dropped by 500,000 kilowatt-hours in 2010, three times more than in 2009. In the Philippines, 1,067 cities and towns participated, with over 15 million Filipinos joining.

About 4,000 cities took part, including landmarks like Big Ben, the Empire State Building, the Sydney Opera House, the Eiffel Tower, the Parthenon, the Brandenburg Gate, and the Forbidden City.

Earth Hour 2011 was the largest event in the campaign's five-year history, showing it was the biggest voluntary action ever.

Measurement of reduction in electricity use

The Earth Hour Global FAQ page explains:

A study from 2014 in the journal Energy Research and Social Science collected 274 measurements of electricity use changes during Earth Hour events in 10 countries over 6 years. The study found that these events led to an average 4% drop in electricity use. It also pointed out the difficulty of turning Earth Hour’s temporary energy savings into lasting changes, such as ongoing behavior changes and long-term investments.

Reception

Criticisms of Earth Hour have included the following:

• Some critics say the drop in energy use during Earth Hour is very small. The Herald Sun compared the energy saved in Sydney's business area to "removing 48,613 cars from the road for one hour." Australian writer Andrew Bolt noted that this saving is so tiny it is not important, similar to removing six cars from the road for an entire year.

• Other environmental experts have criticized Earth Hour for focusing on individual actions, while a few large fossil fuel companies are responsible for most human-made carbon emissions. Adam McGibbon, writing for The Independent, said Earth Hour lets these companies and politicians avoid dealing with climate change.

• The Christian Science Monitor reported that most candles are made from paraffin, a substance from crude oil, a fossil fuel. Depending on how many candles are used, whether people normally use energy-efficient light bulbs, and the energy source used for electricity, using candles instead of lights during Earth Hour might increase, rather than decrease, carbon emissions.

• On March 29, 2009, one day after Earth Hour 2009, Dân Trí Daily News published an article expressing concern that many young people drove around the dark city of Hanoi for fun, using petroleum instead of electricity and causing traffic jams.

• George Marshall of the Climate Outreach Information Network said Earth Hour helps critics of environmentalists by using darkness, which represents fear and decay. He argued that people need to feel hopeful about a better future and that Earth Hour’s message is not helpful.

• The Competitive Enterprise Institute created an event called Human Achievement Hour to celebrate human progress in areas like technology, medicine, and energy. During this hour, they suggest using modern tools such as electricity and indoor plumbing.

• In 2009, economist Ross McKitrick criticized Earth Hour, saying that cheap electricity has been the most important factor in human freedom during the 20th century. He said Earth Hour unfairly criticizes electricity.

• In March 2010, The Daily Telegraph quoted Ross Hayman, a spokesperson for the UK National Grid, saying that turning lights off and then back on quickly might cause problems with electricity production and possibly increase carbon emissions.

• In February 2010, Rick Giles, president of ACT on Campus, a youth group in New Zealand, criticized Earth Hour on a TV show. He argued that Earth Hour is against technology and that people might use candles, which are made from petroleum. He said using technology to solve problems is better than turning off lights.

• The Ayn Rand Institute said that Earth Hour lets people enjoy an hour in the dark, knowing that modern tools like electricity are still available. They suggested instead celebrating Earth Month, where people would live without electricity, heating, or other modern conveniences for an entire month.

• During Earth Hour 2010 in Uusikaupunki, Finland, a 17-year-old motorcyclist hit a 71-year-old man who was walking on the street instead of the sidewalk. The man died from his injuries, while the motorcyclist and her passenger were not hurt. The police said the lack of street lights might have contributed to the accident. The mayor said the lights would have been too dim to prevent it even if they had been on.