Over at Bloomberg, Mark Gimein calls Bitcoin — yes, Bitcoin — an "environmental disaster." Why? Because all that processing power used to mine for new Bitcoins requires a staggering amount of energy:
Mining is a process in which powerful computers create Bitcoins by solving processor-intensive equations. ...
Blockchain.info, a site that tracks data on Bitcoin mining, estimates that in just the last 24 hours, miners used about $147,000 of electricity just to run their hardware, assuming an average price of 15 cents per kilowatt hour … That’s enough to power roughly 31,000 U.S. homes, or about half a Large Hadron Collider.
It's a stunning stat, but does this really count as a "disaster"? That's less clear. After all, we need to consider the counterfactural: Is it possible that these computers would be used for other activities and calculations anyway, if they weren't mining Bitcoins?
In any case, Gimein's piece does touch on a red-hot topic in energy circles — how much electricity does all of our computing and Internet infrastructure actually consume? A 2011 study by Stephen Ruth of George Mason University estimated that the entire global information and communications technology industry accounts for “only about 3–5 percent" of the world’s electricity use. So it has a much smaller environmental footprint than, say, cars, trucks, and planes (which account for 25 percent of all energy demand.)
On the other hand, the Internet's energy needs are expected to swell significantly in the coming years — even though computing keeps getting more energy-efficient. An interesting new study in Science by Diego Reforgiato Recupero finds that Internet traffic volume tends to double every three years. But network energy-efficiency isn't keeping pace. As a result, the world's IT infrastructure will consume 19 percent more energy in 2013 than in 2012.
Interestingly, as Alexis Madrigal explains here, most of the energy used by our computing infrastructure comes from wireless and cellular networks — by contrast, data centers themselves only use about 10 percent of the electricity involved. What's more, those wireless networks don't seem to be improving their energy efficiency all that quickly. That's why overall energy use could keep growing, particularly as cloud computing becomes more widespread.
Bottom line: On the vast scale of environmental disasters, Bitcoin barely registers. And, in the grand scheme of things, the Internet is still relatively green (that's particularly true if it cuts into other activities, like driving). But it's also true that our computing infrastructure is becoming an increasingly significant part of the world's energy demand.