SEATTLE (CBS News) — Amazon shareholders this week defeated a proposal to wean the company off fossil fuels. But the proposal raised a long-debated question: How much climate pollution does Amazon create, anyway?

Unlike most of its peers, Amazon keeps its carbon footprint figures hidden. In February, the company promised to disclose its carbon emissions figures this year although it declined last week to elaborate on its timeline to CBS News.

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Environmental groups, however, say Amazon’s impact is significant, thanks to the company’s enormous size and complexity. Amazon is the fifth-largest U.S. company, with significant operations in retail, logistics, entertainment and cloud computing — which, activists say, is Amazon’s most polluting.

Amazon Web Services is the biggest cloud-computing provider in America. It has over a million customers, ranging from small businesses to the likes of Verizon, Neflix and Unilever. The CIA is even a cloud customer. It’s also one of Amazon’s fastest-growing divisions, along with three other segments that also heavily rely on computing power: third-party sales, advertising and the subscription services around Amazon Prime, said RJ Hottovy, retail sector strategist at Morningstar.

AWS is supported by more than 50 data centers across the world, according to a Greenpeace report earlier this year on the data industry. Each of those centers consumes about as much power as a small town, Gary Cook, senior IT sector analyst for Greenpeace, told CBS News recently.

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“From a carbon footprint, data centers are super energy intensive,” Cook said. “Electricity demand in the U.S. is declining, but data centers are a big growth market.”

Why so much growth? It turns out that internet use, and especially the media-rich internet that many Americans are used to today, consumes a great deal of power. Every video call, text message or “Marvelous Mrs. Maisel” episode has to live on a server somewhere. That all adds up: A study last year of the information and communication industry found that the sector emits as much carbon as flying.

While some of these data centers are powered by wind or solar farms, nearly half still run on fossil fuels, according to Amazon’s figures. Amazon’s heavy presence in Northern Virginia, just outside Washington, D.C., is particularly polluting, according to Greenpeace. Amazon is the largest private utility customer in an area where much of the electricity still comes from natural gas and coal — the dirtiest fuel. Just 12 percent of AWS’ power in Virginia comes from clean energy, Greenpeace said.

CONTINUED AT CBS NEWS: Amazon has yet to reveal its climate footprint

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