Wall Street Journal: To understand the deadlock in the debate on global climate change, take a look at your iPod. The vast majority of the world’s MP3 players are made in China, where the main power source is coal. Manufacturing a single MP3 player releases about 17 pounds of planet-warming carbon dioxide into the atmosphere. IPods, along with thousands of other goods churned out by Chinese factories, from toys to rolled steel, pose a question that is becoming an issue in the climate-change debate. …