Last month, a montage of art that had been turned into an NFT by the digital artist known as Beeple sold for more than $69 million at a Christie’s online auction. (Also last month, an NFT created from a New York Times technology column sold for more than $500,000, with the proceeds going to the Neediest Cases Fund, a Times-affiliated charity.) But, by Mr. Precht’s own calculations, creating the 300 items of digital art that he had planned to sell — 100 each of three art pieces — would have burned through the same amount of electricity that an average European would otherwise use in two decades, he said in an Instagram video late last month. What in the (warming) world?