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36 Million Americans Take Part in WWF's Earth Hour

Zogby Survey Finds Widespread Participation and Increased Environmental Interest Following WWF’s First Global 'Lights Out' Event for Climate Change

World Wildlife Fund announced today that an estimated 36 million Americans took part in Earth Hour, a global event in support for action on climate change that took place March 29, 2008.

According to a survey by Zogby International, approximately 16 percent of the U.S. adult population reported taking part in Earth Hour and 78 percent were aware of the event, which took place globally in more than 400 cities in 35 countries across all 7 continents. 

The survey—conducted both before and after Earth Hour among a sampling of adult U.S. residents—also demonstrated an increased interest in environmental issues, such as climate change and pollution. In addition, utility companies in the flagship US cities of Atlanta, Chicago and Phoenix reported a measurable drop in electricity usage during the hour-long event.

 Among key findings from the Zogby survey:

  • 16% of respondents from across the US reported participating in Earth Hour—an estimated 36 million Americans.
  • Prior to Earth Hour, 76 percent of adult Americans had not heard about Earth Hour.  Post-event, 78 percent had heard about Earth Hour—a 56 point rise in awareness.
  • After Earth Hour, the survey found a 4 percentage point increase in the level of interest in environmental issues like climate change, global warming and pollution (73 percent pre-event versus 77 percent post-event).
  • Approximately 92 percent of people in WWF’s four flagship Earth Hour cities (Chicago, Atlanta, Phoenix and San Francisco) were aware of Earth Hour after the event.
  • More than 2.7 million adults took part in Earth Hour in Chicago. In San Francisco, nearly 1 million adults participated, with about 900,000 taking part in Atlanta and just over 800,000 in Phoenix.
  • During the week leading up to the event, there were more than 6.2 million unique visitors to the website.

“Earth Hour provided millions of Americans with a way to demonstrate their commitment to combating climate change,” said Carter Roberts, President and CEO of World Wildlife Fund. “This strong public support for Earth Hour should serve as a call to action to governments around the world that it is time to take serious steps to reduce energy consumption and global CO2 emissions.”

Beyond the four official US flagship cities of Atlanta, Chicago, Phoenix and San Francisco, WWF estimates that more than 100 cities and towns across the nation took part in the event, including Miami, Denver, Honolulu, Charlotte, Minneapolis, Pittsburgh and St. Louis and many others. Iconic landmarks in the US going dark included the Golden Gate Bridge, Sears Tower, Empire State Building, Coca-Cola billboard in Times Square, Bank of America Plaza (Atlanta), US Airways Arena (Phoenix), Alcatraz and others turned off their lights to symbolize the need to take action on climate change.

While the primary focus of Earth Hour was to raise awareness about climate change and provide people with an opportunity to express concern about the issue, several flagship cities experienced measurable drops in electrical usage, indicating strong participation in the event.

In Chicago, ComEd reported that electricity usage declined 7 percent both in the City of Chicago and throughout its Northern Illinois service territory during Earth Hour. In Atlanta, Georgia Power reported that its customers decreased their electricity usage by nearly 4 percent during Earth Hour. 

WWF officials said the success of Earth Hour was a clear indicator that an increasing number of Americans are concerned about environmental issues and favor actions that would help combat the impact of climate change.

“Climate change is the most urgent environmental issue facing our planet today,” said WWF’s Carter Roberts. “To achieve the greenhouse gas reductions necessary to slow the effects of climate change, it will take a concerted effort from all levels of society—including individuals, businesses, and governments throughout the world. Earth Hour inspires people all around the world to show their commitment and concern.” 

More information about Earth Hour can be found at

Survey Methodology

The studies were commissioned by WWF and conducted by Zogby International, one of the world’s most respected research companies.  A sample of Zogby International’s online panel, which is representative of the adult population of the U.S., was invited to participate.  The first study included 6,231 adult U.S. residents and was conducted March 7 – 10, 2008.  The second survey, which was conducted after the March 29 Earth Hour event, had 7,280 participants and occurred April 4 - 7, 2008. Slight weights were added by region, party, age, race, religion and gender to more accurately reflect the populations.  The margin of error is +/- 1.2 percentage points.  A subset of 4 DMAs was created by screening by residency in Atlanta, Chicago, Phoenix and San Francisco—which were the 2008 Earth Hour U.S. flagship cities.  The margins of error are higher in sub-groups with +/- 4.2 percentage points. 

About WWF

For more than 45 years, WWF has been protecting the future of nature. The largest multinational conservation organization in the world, WWF works in 100 countries and is supported by 1.2 million members in the United States and close to 5 million globally.  WWF's unique way of working combines global reach with a foundation in science, involves action at every level, from local to global, and ensures the delivery of innovative solutions that meet the needs of both people and nature. Go to to learn more.


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