Earth Hour

Conception and start: 2004–2007

In 2004, confronted with scientific findings, WWF Australia met with advertising agency Leo Burnett Sydney to "discuss ideas for engaging Australians on the issue of climate change". The idea of a large scale switch off was coined and developed in 2006, originally under the working title "The Big Flick". WWF Australia presented their concept to Fairfax Media who, along with Sydney Lord Mayor Clover Moore, agreed to back the event. The 2007 Earth Hour was held on March 31 in Sydney, Australia at 7:30 pm, local time.

In October 2007 San Francisco ran its own "Lights Out" program inspired by the Sydney Earth Hour. After their successful event in October, the organisers decided to rally behind the Earth Hour being planned for March 2008.

2008

Earth Hour 2008 was held internationally on March 29, 2008 from 8 p.m. to 9 p.m. local time, marking the first anniversary of the event. With 35 countries around the world participating as official flagship cities and over 400 cities also supporting, Earth Hour 2008 was celebrated on all seven continents. Landmarks all around the world turned off their non-essential lighting for Earth Hour, including the Sydney Opera House (Sydney, Australia), Empire State Building (New York City), Sears Tower (now Willis Tower, Chicago, US), National Monument (Jakarta, Indonesia), Golden Gate Bridge (San Francisco, US), Bank of America Plaza (Atlanta, US), Space Needle (Seattle, US), Table Mountain (Cape Town, South Africa), the Colosseum (Rome, Italy), Azrieli Center (Tel Aviv, Israel), Royal Castle (Stockholm, Sweden), the CN Tower (Toronto, Canada), SM Mall of Asia, SM Science Discovery Center (Manila, Philippines), Suva (Fiji), Nidaros Cathedral (Trondheim, Norway), Petronas Towers (Kuala Lumpur, Malaysia), KL Tower (Kuala Lumpur, Malaysia), Wat Arun Temple (Bangkok, Thailand), The London City Hall (London, England) and the Royal Liver Building (Liverpool, United Kingdom),

The official website for the event, earthhour.org, received over 6.7 million unique visitors in the week leading up to Earth Hour. Other websites took part in the event, with Google's homepage going "dark" on the day Earth Hour took place.

According to a Zogby International online survey, 36 million Americans—approximately 16 percent of the United States adult population—participated in Earth Hour 2008. The survey also showed there was a 4 percentage point increase in the level of interest in environmental issues such as climate change and pollution directly after the event (73 percent pre-event versus 77 percent post-event).

2008 participants

Earth Hour 2008 included 26 major cities worldwide and 300 smaller towns shutting off their lights.

Scheduling

Since Earth Hour for 2008 was on a Saturday, many high schools in the Greater Toronto Area participated by turning off half the lights in classrooms during the last hour of school on Friday, March 28, 2008. Although the tagline of Earth Hour 2008 was officially, "See the difference you can make", the official radio advertisement ended with the tagline, "Dark city, bright idea."

Tel Aviv scheduled their Earth Hour for Thursday March 27, 2008 to avoid conflict with Sabbath. Dublin moved their Earth Hour to between 9 and 10 p.m. due to their northern geographical location.

Reduced energy consumption

According to WWF Thailand, Bangkok decreased electricity usage by 73.34 megawatts, which, over one hour, is equivalent to 41.6 tonnes of carbon dioxide. The Bangkok Post gave different figures of 165 megawatt-hours and 102 tonnes of carbon dioxide. This was noted to be significantly less than a similar campaign initiated by Bangkok's City Hall the previous year in May, when 530 megawatt-hours were saved and 143 tonnes of carbon dioxide emission were cut.

Philippine Electricity Market Corp. noted that power consumption dropped by about 78.63 megawatts in Metro Manila, and up to 102.2 megawatts on Luzon. The maximum demand drop of around 39 MW was experienced at 8:14 p.m. in Metro Manila and of around 116 MW at 8:34 p.m. in the Luzon grid.

Ontario used approximately 900 megawatt-hours less electrical energy during Earth Hour. At one point, Toronto, Ontario saw an 8.7% reduction in consumption as compared to a typical March Saturday night.

Ireland, as a whole, had a reduction in electricity use of about 1.5% for the evening. In the three-hour period between 6:30 p.m. and 9:30 pm, there was a reduction of 50 megawatts, saving 150 megawatt-hours, or approximately 60 tonnes of carbon dioxide.

In Dubai, where external lighting on several major city landmarks was turned off and street lighting in selected areas was dimmed by 50%, the Electricity and Water Authority reported savings of 100 megawatt-hours of electricity. This represented a 2.4% reduction in demand compared to before the hour began.

The best result was from Christchurch, New Zealand, with the city reporting a drop of 13% in electricity demand. However, national grid operator Transpower reported that New Zealand's power consumption during Earth Hour was 335 megawatts, higher than the 328 megawatt average of the previous two Saturdays. Melbourne, Australia reduced demand by 10.1%. Sydney, being the city that participated in both the 2007 and 2008 Earth Hours, cut electricity consumption by 8.4%. This is less than the previous year's 10.2%; however, Earth Hour executive director Andy Ridley made the claim that after factoring margin of error, the participation in this city was the same.

The worst result was from Calgary, Canada. The city's power consumption actually went up 3.6% at the hour's peak electricity demand. Calgary's weather plays a large role in power consumption, and the city experienced weather 12 °C (around 22 °F) colder than the previous Saturday's recorded temperature in the inaugural year. Enmax, the city's power supplier, has confirmed that in all subsequent years, Calgarians have not supported the Earth Hour initiative, noting that power consumption changed only marginally during the hour in 2010 and 2011 (1% or less) and in 2012 and 2013 showed no appreciable change in power usage at all.

Celebrations around the world

The Danish royal palaces, Amalienborg Palace and Gråsten Palace, went dark at the Queen's command.

Nelly Furtado held a free concert at Nathan Phillips Square in Downtown Toronto to celebrate Earth Hour.

In Toronto, Ontario, York University's student-run Environmental Outreach Team ran an afternoon Earth Hour information session, and the York University Observatory offered an extra public viewing session.

Stargazing activities were held in Toronto's Ontario Science Centre and Richmond Hill's David Dunlap Observatory.

Astronomy Ireland set up high-powered telescopes in Dublin's Phoenix Park to allow people to take advantage of the night sky, normally swamped by bright city lights.

In Tel Aviv, Israel, a free concert by Knesiyat Hasekhel was held at Rabin Square. Power needed for the concert was generated by a group of cyclists pushing pedal generators. The rest of the power was supplied by generators burning used falafel oil for power.

In Atlanta, the CEO of WWF US, Carter Roberts, and the Mayor of Atlanta, Shirley Franklin, flipped a giant switch on live TV, symbolically starting the wave of lights going out on the buildings around the city.

In San Francisco, a public event hosted by WWF US was attended by Mayor Gavin Newsom, Gold medal figure skater Brian Boitano, Grateful Dead drummer Mickey Hart, and other celebrities. They gathered to watch the lights go out, listening to the music of Jason Damato.

In Kuala Lumpur, Malaysia, the lights of the world's tallest twin towers, the Petronas Towers, were turned off.

Google

Earth Hour 2008 received free publicity from the Google corporation. From 12:00 a.m. on March 29, 2008 until the end of Earth Hour, the Google homepage in the United States, Colombia, Canada, Denmark, Ireland and the UK was turned to a black background, with the tagline "We've turned the lights out. Now it's your turn – Earth Hour." However, Google stated that for 2009 they would not turn the page black again due to the confusion it caused many users. A common misconception is that having a black background on a web page reduces the power consumption of monitors; LCD monitors use a constant amount of power regardless of which colors are shown. This is not the case for organic LED monitors, though they are not currently in popular use.

TV channels

Earth Hour was covered extensively in the United States with segments on The Oprah Winfrey Show, NBC Nightly News, CBS Evening News, The Today Show, Good Morning America, CNN, CNN International, The Weather Channel and more. Several stations around the United States went live with their coverage, including Atlanta NBC station WXIA-TV, who did an hourlong Earth Hour special during the event.

Canada's The Weather Network moved its studios outside between 8 and 9 pm. EDT for Earth Hour, using only an LED light for the hour.

The Agenda with Steve Paikin on TVOntario ran its full program running only on candlelight.

2009

Earth Hour 2009 was from 8:30 p.m. to 9:30 p.m. local time, March 28, 2009. The campaign was titled "Vote Earth" and was dubbed "the world's first global vote" with one billion votes was the stated aim for Earth Hour 2009, in the context of the pivotal 2009 United Nations Climate Change Conference. WWF reported that 88 countries and 4,159 cities participated in Earth Hour 2009, ten times more cities than Earth Hour 2008 had (2008 saw 400 cities participate).

Among the participants in 2009 was, for the first time, the United Nations Headquarters in New York City.

In Egypt, the lights went out on the Sphinx and the Great Pyramids of Giza from 8:30 to 9:30 pm.

The Philippines saw participation from 647 cities and towns; over 10 million Filipinos were estimated to have joined in the hour-long lights-off. This was followed by Greece with 484 cities and towns participating, and Australia with 309.

Despite official organisers WWF stating that the event is not about the reduction in electricity, a number of public institutions reported on electricity savings in their cities to see participation numbers. The Canadian province of Ontario, excluding the city of Toronto, saw a decrease of 6% in electricity usage while Toronto saw a decrease of 15.1% (nearly doubled from 8.7% the previous year) as many businesses darkened, including the landmark CN Tower.

The Philippines was able to save 611 MWh of electricity during the time period, which is said to be equivalent to shutting down a dozen coal-fired power plants for an hour.

Swedish electricity operator Svenska Kraftnät recorded a 2.1% decrease in power consumption from its projected figure between 8 p.m. and 9 pm. The following hour, the corresponding number was 5%. This is equivalent to the consumption of approximately half a million households out of the total 4.5 million households in Sweden.

According to Vietnam Electricity Company, Vietnam's electricity demand fell 140 MWh during Earth Hour.

Participation

96 countries and territories on 6 continents participated in the event in 2009.

Participating television and radio stations

The National Geographic Channel suspended regular programming for an hour and showed how to reduce energy consumption during Earth Hour.

National Geographic Channel Asia suspended broadcast on March 28, 2009 from 8:30 p.m. to 9:30 p.m.

Cartoon Network and Magic 105.4 FM broadcast Earth Hour at 20:30 for the event.

Malaysia's 8TV halted transmission for one hour starting from 20:30

DhiTV and Villa TV halted transmission for one hour in Maldives from 20:30.

Canal 5 in Mexico halted transmission for one hour in Mexico City at 20:30.

Philippine network ABS-CBN turned off the lights in their studio from 20:30 to 21:30.

Naga City internet radio stations Zone105 and XFM Naga went offline at 20:30.

Radiotelevisión Española (RTVE) turned off the lights in their newsrooms and their sets.

2010

Earth Hour 2010 was held from 8:30 p.m. to 9:30 p.m. local time on March 27. In Israel, the hour was held on April 22.

126 countries participated in Earth Hour 2010.

In the United States polling showed that an estimated 90,000,000 Americans participated in Earth Hour as lights were turned off around the country, including landmarks such as Mount Rushmore, the Las Vegas Strip, the Empire State Building and Niagara Falls.

Some cities and landmarks took the opportunity to make more long-term adjustments to their everyday power consumption. In Chicago, the Building Owners and Managers Association (BOMA) developed lighting guidelines to reduce light pollution and reduce the carbon footprint of downtown buildings. Mount Rushmore in South Dakota started powering down each night around 9 p.m. instead of 11 p.m.

In Vietnam, electricity demand fell 500,000 kWh during Earth Hour 2010, which was three times larger than the first time the country joined the event in 2009.

In the Philippines, 1,067 towns and cities pledged participation in 2010 and over 15 million Filipinos participated in the event.

About 4000 cities participated, including landmarks such as Big Ben, the Empire State Building, the Sydney Opera House, the Eiffel Tower, the Parthenon, the Brandenburg Gate, and the Forbidden City.

Celebrity Earth Hour ambassadors included South African Archbishop Desmond Tutu, former New Zealand Prime Minister Helen Clark, President of Vietnam Nguyễn Minh Triết, and London Mayor Boris Johnson.

Earth Hour garnered support from many corporations including Coca-Cola Enterprises, Wells Fargo, IKEA, HSBC, PwC, Accenture and Nokia Siemens Networks.

Participating TV channels and radio stations

National Geographic Channel Asia and Cartoon Network both suspended broadcasting from 8:30 p.m. to 9:30 p.m.

In the Philippines, GMA Network turned off lights in their building from 8:30 p.m. to 9:30 p.m, while ABS-CBN stopped broadcasting and turned off their lights.

Vietnam's FBNC channel joined hands with Earth Hour Vietnam.

The Agenda with Steve Paikin on TVOntario ran its full program running only on candlelight again.

Innovative environmental media

Australian advertising agency Wunderman Sydney produced a marketing piece to support Earth Hour, their pro-bono client since 2009. To encourage businesses to participate in Earth Hour 2010, five-thousand 'Plant Spikes' were produced and distributed to offices around Australia. The spike was designed to be inserted in office pot plants by plant hire company TPR Group as they serviced plants in businesses nationwide.

To ensure the spike was completely environmentally friendly, the agency partnered with printer STI Lilyfield to invent an organic printer's ink containing natural plant fertilizer derived from Durvillaea potatorum and extract of Ascophyllum nodosum to promote healthy plant growth and improve resistance to insect and fungal attack. Printed on 100% FSC-certified paper, this ink fertilized the pot plants as the spike biodegraded naturally in the plant's soil.

2011

Earth Hour 2011 was the biggest year in the campaign's five-year history, reaffirming it as the largest ever voluntary action for the environment. In 2011, the tagline "Beyond the Hour" was adopted by organisers as a way to encourage people to take their commitment to the cause beyond the 60-minute event. Together with agency Leo Burnett, Earth Hour unveiled an updated planet themed logo that included a small plus symbol to the right of the signature "60" which was used in previous years. The 60+ symbol continues to be the main logo used by campaign organisers around the world.

Earth Hour 2011 took place in a record 5,251 cities and towns in 135 countries and territories on all seven continents. It had an estimated reach of 1.8 billion people across the globe. In addition to this, the campaign's digital footprint grew to 91 million.

In 2011, some of the world's most well-known landmarks, including the Forbidden City, Eiffel Tower, Buckingham Palace, Golden Gate Bridge, Table Mountain, Christ the Redeemer statue and Sydney Opera House switched off their lights for Earth Hour's global "lights out" event.

In India, Earth Hour 2011 was held on March 26, 2011 from 8:30 p.m. to 9:30 pm. IST, flagged off by the Chief Minister of Delhi Sheila Dixit and Earth Hour 2011 Ambassador and Bollywood actress Vidya Balan in the presence of Jim Leape, Director General, WWF International. Rosebowl channel suspended broadcasting from 8.30 p.m. to 9.30 p.m. to mark the observance of Earth Hour.

In Azerbaijan, Maiden Tower darkened for Earth Hour.

The Philippines, which has been an active participant of the Earth Hour, had an early "earth hour" when power was accidentally interrupted, plunging Metro Manila and nearby provinces into darkness. After power was restored, major buildings, commercial centers and residential areas in Metro Manila and most provinces continued to turn off their lights, while participating channels in the Philippines, ABS-CBN and Cartoon Network halted their transmissions for an hour.

30 provinces and cities in Vietnam took part in Earth Hour 2011 with the main event held in Nha Trang. The nation's electricity demand fell 400,000 kWh, one-fifth less than the previous year's. Vietnam managed to save 500 million VND (US$23,809) thanks to the saved power.

YouTube promoted the Earth Hour by changing its logo, and by adding a switch on/off feature near the title of each video, so that users could change the background color from white to black.

One of the least co-operative areas traditionally has been Alberta; in 2008, Calgary's power consumption went up during Earth Hour. The trend continued in 2011 when Edmonton's power usage also increased. While Calgary's power usage went down in 2011 during the event, electricity officials could not distinguish their readings between normal usage and a conscious attempt to participate.

2012

It was announced that the Earth Hour Global headquarters was moving from Sydney to Singapore in February 2012. A launch event took place at ION Orchard on February 20, with the move supported by Singapore's Economic Development Board (EDB) and WWF-Singapore.

Earth Hour 2012 was observed on March 31, 2012 from 8:30 p.m. to 9:30 p.m. (participants' local time). It took place in more than 7000 cities and towns across 152 countries and territories, making it the biggest growth year for the campaign since 2009. It was also the first year that Earth Hour was celebrated in space, with Dutch astronaut André Kuipers tweeting at various moments during the event's trek around the globe.

I Will If You Will

The global theme for WWF's Earth Hour in 2012 was "I Will If You Will", a two-year campaign aimed to engage the movement's followers to go beyond 60 minutes and to challenge their own networks of friends to become more environmentally conscious throughout the year. Using a YouTube platform, the campaign saw video challenges set by celebrities, politicians, organisations and everyday individuals that were fulfilled when a designated number of accepts were achieved on the platform.

The campaign was supported by supermodel Miranda Kerr, who conducted a free yoga class after 500 fans accepted her challenge, and Greenpeace Executive Director Kumi Naidoo who dyed his beard green at the Rio+20 Conference in South Africa after 10,000 people accepted his challenge to support Earth Hour.

As in the previous year, YouTube changed its logo and added a light switch feature near video titles, so that users could change the background color from white to black. This support helped generate 4.6 million hits on the "I Will If You Will" platform during the week of Earth Hour, with more than 200,000 people personally pledging to take a direct action beyond the 60-minute event.

Environmental legislation change in Russia

WWF-Russia generated 122,000 signatures on an Earth Hour petition to strengthen "oil pollution" laws for marine waters of Russia. The petition was entered into the Russian parliament after the March event, and a strengthened law to protect the country's seas was passed in December that year. WWF-Russia had used the "I Will If You Will" challenge idea to generate signatures on the petition, with various Russian celebrities including politician and former boxer Nikolai Valuev challenging the country to sign the petition.

2013

Earth Hour 2013 was held across the world on Saturday, March 23 at 8:30 p.m. to 9:30 p.m. local time to avoid taking place after European Summer Time began, ensuring a greater impact for the lights-off event. It was also changed to avoid coinciding with the Christian Holy Saturday, which fell on March 30 of that year.

Globally, there was a continuation of the "I Will If You Will" theme, with certain countries and territories producing video challenges from notable ambassadors to encourage participation in the event and certain environmental actions. Organisers note that in 2013, many countries and territories began producing environmental outcomes through the event.

Africa

In 2013, the world's first Earth Hour Forest began in Uganda, an ongoing project that aims to restore 2700 hectares of degraded land. Standard Chartered Bank-Uganda pledged to help fill the forest with more than 250,000 trees.

Earth Hour commemorations in Madagascar had as their highlight the distribution of one thousand wood-saving stoves to victims of the cyclone Haruna in the southern town of Toliara, extensively damaged in February 22 storm. WWF-Madagascar and ADES (Association pour le Développement de l'Energie Solaire) distributed an additional 2,200 wood-saving stoves later that year.

Former President of Botswana, Festus Mogae promised to plant one million indigenous trees over four years, as part of his "I Will If You Will" challenge for Earth 2013. He planned to kick off his IWIYW challenge by planting 100,000 trees in a severely degraded area in Southern part of the country called Goodhope. The remaining trees were to be planted in other parts of the country which were also in need of land rehabilitation, such as in the North Eastern and Western regions of Botswana.

Europe

WWF-Russia launched its 2013 campaign aiming to secure more than 100,000 signatures from Russian citizens to petition for amendments to the current forest legislation. The petition reached more than 127,000 signatures before the Earth Hour event, ensuring the legislation was debated in the State Duma by politicians.

At the global media launch for Earth Hour 2013, CEO and co-founder Andy Ridley spoke about the movement's significant environmental outcomes beyond the hour: "People from all walks of life, from all nations around the world, are the lifeblood of the Earth Hour interconnected global community. They have proven time and time again that if you believe in something strongly enough, you can achieve amazing things. These stories aren't unique, this is happening all over the world," he said.

Participating countries

Earth Hour 2013's participants included:

Spain

Hong Kong

Bulgaria

Samoa

Fiji

New Zealand

Australia, Sydney Opera House and Sydney Harbour Bridge

Argentina

Iran, Milad Tower, Saat Tower, Siosepol and Naqsh-e Jahan Square

New Caledonia

Papua New Guinea

Japan, Tokyo Tower

South Korea

Philippines

Indonesia

Norway

Malaysia, Petronas Towers

Taiwan, Taipei 101

Singapore, Marina Bay Sands

China, The Bird's Nest (stadium) (Beijing)

South Africa

India, Gateway of India

Dubai, Burj Khalifa

Bahrain, Bahrain World Trade Center, Al Fateh Grand Mosque, Isa Cultural Centre, Electricity and Water Authority, Bahrain International Circuit and the Al Moayyed Tower

United Arab Emirates, Shaikh Zayed Grand Mosque and Shaikh Zayed Bridge

Greece, Acropolis of Athens, White Tower of Thessaloniki

France, Eiffel Tower

England, Big Ben, Houses of Parliament

Italy, David in Florence

Denmark, Copenhagen's Little Mermaid statue

Canada, all 30 National Hockey League arenas (7 of which are in Canada), Hamilton Utilities and Horizon Utilities

United States of America

all 30 National Hockey League arenas (23 of which are in the United States)

LAX

Iceland

Participating organisations

Multinational participation:

Anschutz Entertainment Group, 58 venues

Barclays Plc, Barclays Center Brooklyn and several other centers

2014

Earth Hour 2014 took place on Saturday, March 29, during the same 8:30 to 9:30 pm local timeslot. Earth Hour Blue was launched as a global crowdfunding and crowdsourcing platform for the planet. "It is all about the collective effort of individuals around the world getting together to help fund or add their voice to support on-the-ground environmental and social projects that deliver real outcomes."

The Earth Hour 2014 Report highlighted a broad range of environmental outcomes achieved by the movement across 162 countries and territories around the world. More than US$60,000 was raised on the Earth Hour Blue platform for grassroots environmental projects run by WWF. The movement also saw campaigns to help protect Australia's Great Barrier Reef, the launch of a Blue Sky App in China, and the delivery of thousands of wood efficient stoves to communities in Madagascar.

The event was also supported by the cast and producers of The Amazing Spider-Man 2, who attended the Earth Hour event held by WWF-Singapore.

2015

Earth Hour 2015 took place on Saturday, March 28, again between 8:30 and 9:30 pm local time. The tagline for the global campaign was "Change Climate Change", returning to the movement's original focus to initiate citizen action on global warming. A day before the event, over 170 countries and territories had confirmed their participation; with more than 1200 landmarks and close to 40 UNESCO world heritage sites set for the switch off.

For the second year running, Earth Hour Blue aims to raise funds for WWF organised climate focused projects on a crowdfunding platform. This year, crowdfunding projects include solar light distribution in the Philippines and India, and wildlife based projects from Colombia, Uganda and Indonesia.

Uniquely participating in the Earth Hour activity are the inhabitants of an island called Sibuyan in the Philippines who turned on their lights to elevate the message of using renewable energy. The island's source of electricity is a mini-hydro power plant.

2016

Earth Hour 2016 was on Saturday, March 19, from 8:30 p.m. to 9:30 p.m. during participants' local time. It was also changed to avoid coinciding with the Christian Holy Saturday, which fell on March 26 of that year. It was the 10th year anniversary of the campaign's beginnings in Sydney, Australia. Östersund in Sweden cancelled the 2016 event, following a spate of sex attacks, highlighting safety as a subject for discussion when saving resources. Almost all the countries in the world observed Earth Hour, Pakistan also observed this day

Celebrity endorsements

Earth Hour has been supported around the world by Nelson Mandela, supermodel Miranda Kerr, footballer Lionel Messi, the United Nations Secretary General Ban Ki-moon, Greenpeace International Executive Director Kumi Naidoo, former US Vice President Al Gore, the President of Fiji Ratu Epeli Nailatikau, André Kuipers and the International Space Station, actress Isabel Lucas, TV stars Bill and Giuliana Rancic, Yoko Ono, Stephen Fry, Cate Blanchett, Coldplay, among many others.

In 2014, Earth Hour was supported by Sony Pictures and the cast of The Amazing Spider-Man 2, including actors Andrew Garfield, Emma Stone, Jamie Foxx and director Marc Webb. The cast put their support behind Earth Hour Blue crowdfunding projects, asking their fans to raise funds for on-the-ground environmental projects from across the world. Spider-Man and its cast and director also attended the WWF-Singapore Earth Hour event in 2014.

Actress and co-founder of The Honest Company, Jessica Alba, was the Earth Hour 2013 global ambassador. Supermodel Miranda Kerr served as global ambassador in 2011 and 2012, helping launch Earth Hour's "I Will If You Will" platform.

Chinese actress Li Bingbing has been a longtime supporter of the campaign, attending WWF-China's Earth Hour events each year. Supermodel Gisele Bündchen is also a longtime supporter of Earth Hour, taking to social media to encourage fans in Brazil and around the world to switch off.

Organisations that support Earth Hour

Earth Hour is supported around the world by Woodland, CBRE Group, the National Hockey League, FIFA, UEFA, Manchester United, Hilton Worldwide, Girl Scouts of the US, World Organisation of the Scouts Movement, UNESCO, the UN Environment Programme, the International Trade Union Confederation, HSBC, World Association of the Girl Guides and Girl Scouts, Philips, IKEA, The Body Shop, ING Vysya Bank and more.

Measurement of reduction in electricity use

The Earth Hour Global FAQ page states:

Earth Hour does not purport to be an energy/carbon reduction exercise, it is a symbolic action. Therefore, we do not engage in the measurement of energy/carbon reduction levels for the hour itself. Earth Hour is an initiative to encourage individuals, businesses and governments around the world to take accountability for their ecological footprint and engage in dialogue and resource exchange that provides real solutions to our environmental challenges. Participation in Earth Hour symbolises a commitment to change beyond the hour.

A 2014 study published in Energy Research and Social Science compiled 274 measurements of observed changes in electricity demand caused by Earth Hour in 10 countries, spanning 6 years, and found that the events reduced electricity consumption an average of 4%. The study noted the policy challenge of converting Earth Hour's short-term energy saving into longer-term actions, including sustained changes in behavior and investment.

Criticism

Some critics point out that the reduction in power consumption in most cases is insignificant. The Herald Sun equated the power savings in the Sydney central business district to "taking 48,613 cars off the road for 1 hour". Australian columnist Andrew Bolt pointed out that "A cut so tiny is trivial – equal to taking six cars off the road for a year".

Other criticisms of Earth Hour have included the following:

The Competitive Enterprise Institute has introduced an opposing Human Achievement Hour in celebration of human progress in various fields of industry, including technology, medicine, energy, and more. During this hour, the Institute suggests that people celebrate by using modern technology such as electricity, telecommunications and indoor plumbing.

Bjørn Lomborg, author of The Skeptical Environmentalist, wrote, "It is vital to make solar and other new technology cheaper than fossil fuels quickly so we can turn off carbon energy sources for a lot longer than one hour and keep the planet running... Fossil fuels literally gave us an enlightenment, by lighting our world and giving us protection from the fury of the elements. It is ironic that today's pure symbolism should hark back to a darker age."

Bjørn also pointed out the feel-good factor Earth Hour creates, noting that it is an "ineffective feel good event" that makes people feel they are doing something for the environment, while in reality the amount of carbon emissions reduced by the earth hour is negligible.

The Christian Science Monitor said that most candles are made from paraffin, a heavy hydrocarbon derived from crude oil, a fossil fuel, and that depending on how many candles a person burns (if one uses candles during Earth Hour), whether or not they normally use compact fluorescent light bulbs, and what source of energy is used to produce their electricity, in some cases, replacing light bulbs with candles will cause an increase, instead of a decrease, in carbon dioxide emissions.

On March 29, 2009, one day after Earth Hour 2009, Dân Trí Daily News published an editorial expressing concern that many young people chose to drive around the darkened city of Hanoi for fun, exhausting petroleum instead of electricity and resulting in long traffic jams.

In 2009, economist Ross McKitrick criticized the idea, saying, "Abundant, cheap electricity has been the greatest source of human liberation in the 20th century.[...] The whole mentality around Earth Hour demonizes electricity."

In March 2010, The Daily Telegraph quoted Ross Hayman, head of media relations at the UK National Grid, as saying "it could therefore result in an increase in carbon emissions" due to complications related to rapidly lowering then raising electricity generation.

In February 2010, Rick Giles, president of ACT on Campus, the youth wing of New Zealand's ACT Party, appeared on the morning television show Sunrise to denounce Earth Hour and instead suggested the celebration of "Edison Hour". He argued that Earth Hour is an "anti-technology" cause, and that people will simply use candles instead, which is undesirable as they are petroleum-based. He argued that if we are heading for some kind of disaster, it makes sense to use technology to combat this. Rick said "I think my argument is so powerful that it's not necessary to talk about it".

The Ayn Rand Institute wrote, "Participants spend an enjoyable sixty minutes in the dark, safe in the knowledge that the life-saving benefits of industrial civilization are just a light switch away... Forget one measly hour with just the lights off. How about Earth Month... Try spending a month shivering in the dark without heating, electricity, refrigeration; without power plants or generators; without any of the labor-saving, time-saving, and therefore life-saving products that industrial energy makes possible."

Expressing sarcastic support for Earth Hour, the pro-carbon Carbon Sense Coalition wants Earth Hour to be renamed "Blackout Night", and to be held outside on the shortest and coldest day of the year "...to prepare our population for the dark days ahead".

During the 2010 Earth Hour in the city of Uusikaupunki in Finland, a 17-year-old female motorcyclist hit a 71-year-old man, who was walking on the street instead of the sidewalk for an unknown reason. The man died from his injuries, while the motorcyclist and her passenger were uninjured. At the time of the accident the street lights had been turned off as part of the Earth Hour. The police stated that the lack of street lighting may have played a part in the accident, while the mayor believed the city's street lights would have been too dim to prevent it even if they had been on.

Jeremy Clarkson, ex-host of the BBC motoring programme Top Gear, claimed switching on all electrical items in his home as a protest against the perceived impact of Earth Hour, claiming the event would have little to no effect on attitudes towards climate change.