on the back of
中国が米国を抜いて世界一の石油輸入国になりました。ただその背景には米国国内の石油生産量がエネルギーの自立に向かって大きく舵を取ったという事情があります。
China overtakes U.S. as world's top oil importer
China has overtaken the US as the world's largest net importer of oil, in a generational shift that will shake up the geopolitics of natural resources.
US net oil imports dropped to 5.98m barrels a day in December, the lowest since February 1992, according to provisional figures from the US Energy Information Administration. In the same month, China's net oil imports surged to 6.12m b/d, according to Chinese customs.
中略
US domestic oil production is booming on the back of the shale revolution, reducing the need for crude oil imports. In addition, US super-majors and refiners such as ExxonMobil and Phillips 66 are exporting record quantities of oil products to meet soaring demand for gasoline, diesel and kerosene in Latin America and Africa, lowering the country's net oil imports.
US oil production surged last year by more than 800,000 b/d. The rise in domestic production has allowed the country to lessen its dependence on the Opec oil cartel. But the reduction has been uneven, with Saudi Arabia, Kuwait and other Middle East countries suffering relatively little from reduced US demand compared to African producers such as Angola and Nigeria.
http://edition.cnn.com/2013/03/04/business/china-u-s-oil-importer/index.html?hpt=ias_c2
on the back ofというイディオムはas a result ofやafterと同じ意味合いで使われます。したがって「シェールガス革命の結果」という意味になります。ただ、複数の新聞・通信社記事の訳をながめると、「シェールガス革命に後押しされて」「シェールガス革命のおかげで」など、よりこなれた形で処理しているところが多いようです。（UG）
