Study: More than 6 million could die early from air pollution every year

Photos: What's causing climate change? Meet the top 10 villains
Electricity and heat: 30.6% – Burning fossil fuels for electricity and heat is, by far, the main driver of climate change. Emissions from those sectors account for nearly a third of global greenhouse gas emissions, according to the World Resources Institute. These activities are the biggest climate villains, statistically speaking.
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Photos: What's causing climate change? Meet the top 10 villains
Transportation: 14.8% – Transportation -- driving, flying and the like -- makes up nearly 15% of global climate-change pollution, according to 2012 data synthesized by WRI. It's the second-most important cause of dangerous global warming.
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Photos: What's causing climate change? Meet the top 10 villains
Manufacturing and construction: 13.3% – Manufacturing and construction are less often discussed than transit, but they contribute nearly as much to climate change: 13.3% of emissions, WRI says. These activities are the third-biggest contributors of heat-trapping emissions.
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Photos: What's causing climate change? Meet the top 10 villains
Agriculture: 11.1% – Likewise, our food systems are villains in the fight against climate change. Advocates say giving up meat, especially beef, would help curb greenhouse gases. Agriculture makes up 11.1% of global emissions, according to WRI.
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