Retailers, consumers and prices
The Las Vegas strip (below) and other global icons went dark on Saturday for Earth Hour.
McDonald’s powered down in Chicago. Twitter was alight with Earth Hour tweets.
The annual event, launched in 2007 by the World Wildlife Fund, aims to encourage people to cut energy use and curb greenhouse gas emissions from fossil fuels.
World emissions have risen by about 70 percent since the 1970s. China has recently overtaken the United States as the top emitter, ahead of the European Union, Russia and India.