【Economist】Bitcoin: The dirty truth

新英文杂志 2021-04-12 23:29



Totting up the cryptocurrency’s environmental costs

AS COINBASE’S IPO shows, cryptocurrencies have many fans. But they have detractors, too. Environmentalists, in particular, fret about how much energy bitcoin uses. In a paper in Nature Communications, a group of academics led by Dabo Guan of Tsinghua University and Shouyang Wang at the Chinese Academy of Sciences examine bitcoin’s energy use in China. They conclude that, in the absence of legal curbs, bitcoin could by 2024 become a “non-negligible” barrier to China’s efforts to decarbonise its economy.

Bitcoin’s hunger for energy stems from its design. It forgoes centralised record-keeping in favour of a “blockchain”, a transaction database that is distributed among users. The blockchain is maintained by “miners”, who validate transactions by competing to crack mathematical puzzles with solutions that are hard to find but easy to check. Each successfully mined block of transactions generates a reward, currently 6.25 bitcoins ($357,000).

The system varies the difficulty of the puzzles to ensure that one new block is created, on average, every ten minutes. High bitcoin prices make it worthwhile to spend more computing power—and therefore electricity—chasing mining rewards. But bitcoin’s automatic stabilisers will ramp up the mathematical difficulty in response. Like the Red Queen in “Through the Looking-Glass”, competing miners find themselves running faster simply to stand still.

Despite the currency’s democratic ambitions, mining is concentrated among a handful of professional operators. About 70% takes place in China. The researchers use economic modelling to try to work out how much carbon all this make-work produces. They conclude that, without regulation, Chinese bitcoin mining could consume around as much energy as Italy or Saudi Arabia by 2024. Annual carbon emissions, at 130m tonnes, would approach those of Nigeria.

Such numbers should be taken with a good deal of salt. Bitcoin’s energy use depends crucially on its price, which swings wildly. The authors assume that the long-term trend will be upward, because the rate at which new bitcoins are created is designed to halve every four years. Reality will doubtless prove more complicated. But the general picture—that bitcoin is a dirty business—fits with other research. One oft-cited model, which uses publicly available blockchain data, reckons its global energy consumption is already equal to that of Kazakhstan, and that its carbon footprint matches Hong Kong’s. 


Apr 10th 2021 • Finance and economics • 477 words



文章第五段第一句话“Such numbers should be taken with a good deal of salt. " 中的 taken with a good deal of salt 如何理解

注意这里化用了 take with a grain/pinch of salt 这一习语,英文释义为 to accept sth but to maintain a degree of skepticism about its truth.。看一个例句 You have to take these findings with a grain of salt because respondents tend to give the answers they feel they should.你必须对这些结果有所保留,因为调查对象们倾向于给出他们认为应该给的答案。

🔔 查看本文更多讲解、全文翻译,欢迎加入《阅读训练营》

🔔 扫码下方二维码添加小编微信进读者群获取每周推文PDF


本文全文摘选自The Economist/《经济学人》(Apr 3rd, 2021),仅供个人学习交流使用,欢迎转发至朋友圈。

©2021 新英文杂志(每日精选优质外刊文章,始于2016年3月,无其它品牌或分号)