Do a Google search for "37 million barrels" AND China, and you'll find at the beginning of the year Reuters reported:
Chinese people use up to 3 billion plastic bags a day and the country has to refine 5 million tons (37 million barrels) of crude oil every year to make plastics used for packaging, according to a report on the Web site of China Trade News (www.chinatradenews.com.cn).
The Chinese government is banning production and distribution of the thinnest plastic bags in a bid to curb the white pollution that is taking over the countryside...The move may save as much as 37 million barrels of oil currently used to produce the plastic totes, according to China Trade News.
Either I'm missing a browser plugin of some kind, or the China Trade News website is in Chinese. In any case, I haven't seen the original claim so it is a little hard to place in context, but I don't need to in order to know that the Chinese bag regulation will not--as Scientific American and legions of (less-reputable) sources claim--"save 37 million barrels of oil."
First, that original 37-million-barrel figure referred to "plastics used for packaging," which might include packaging other than the plastic bags affected by the new rule. Second, the Chinese government has not announced plans to ban all bags, but only bags less than 0.025 mm thick. That means it would be illegal to produce the equivalent of a grocery or dry cleaning bag, but something as thick as a bread bag or boutique retail bag would still be legal as long as they have a price tag on them (the law prohibits complimentary plastic bags). Third, even if every single plastic product in the 37-million-barrel figure stopped being produced, the regulation only saves that amount if nothing replaces them.
This little game of journalistic telephone shows that, yes, the plastic bag really does epitomize modern environmental debate. A similar distortion was recently uncovered in the figures used to describe plastic bag impacts on wildlife:
The central claim of campaigners is that the bags kill more than 100,000 marine mammals and one million seabirds every year. However, this figure is based on a misinterpretation of a 1987 Canadian study in Newfoundland, which found that, between 1981 and 1984, more than 100,000 marine mammals, including birds, were killed by discarded nets. The Canadian study did not mention plastic bags.
Fifteen years later in 2002, when the Australian Government commissioned a report into the effects of plastic bags, its authors misquoted the Newfoundland study, mistakenly attributing the deaths to "plastic bags."