As the great research ship Chikyu left Shimizu in January to mine the explosive ice beneath the Philippine Sea, chances are good that not one of the scientists aboard realized they might be closing the door on Winston Churchill’s world. Their lack of knowledge is unsurprising; beyond the ranks of petroleum-industry historians, Churchill’s outsize role in the history of energy is insufficiently appreciated. Winston Leonard Spencer Churchill was appointed First Lord of the Admiralty in 1911. With characteristic vigor and verve, he set about modernizing the Royal Navy, jewel of the empire. The revamped fleet, he proclaimed, should be fueled...