Tensions in the South China Sea—scene of naval standoffs in the past year as China has pressed its smaller neighbors on the open sea—may seem far off to many Western investors, but any conflict in the region could affect the global economy.

Coast guard vessels from China (rear) and Vietnam in a disputed part of the South China Sea near China's oil drilling rig, May 14, 2014.

There are no definitive government estimates about the amount of global trade passing through the South China Sea, but the United Nations Conference on Trade and Development estimated that 8.4 billion tons—or about half of the world's annual merchant fleet tonnage—passed through the region in 2010.