THE GEOGRAPHY OF TRANSPORT SYSTEMS
Source: WTO.
Changes in the Value of World Trade per Type of Merchandise, 1950-2007
Specific segments of international trade are subject to much volatility, particularly fuel and mining trade (e.g. petroleum), which began to diverge in the 1970s. Commodity chains are thus subject to some level of uncertainty in assessing its growth potential and the necessary level of investment in transport infrastructure, let it be for modes or terminals.