THE GEOGRAPHY OF TRANSPORT SYSTEMS
| Oil Field | Output (MBD) | % of National Output | Status |
| Ghawar (Saudi Arabia) | 4.5 | 40% | Possibly declining |
| Cantarell (Mexico) | 2.0 (1.7 in 2007) | 60% | Declining |
| Burgan (Kuwait) | 1.7 | 68% | Declining |
| DaQing (China) | 1.0 | 40% | Possibly declining |
Source: adapted from D. Luhnow (2006) "Mexico's Oil Output May Decline Sharply," Wall Street Journal, Feb 9.
Global oil production is peaking at the same time that there is a surge in new demand from newly industrialized countries. The world's largest oil fields have reached optimal output, with some declining. For instance, the Cantarell oil field in Mexico was assessed to be possibly declining in 2005. In 2007, its output declined to 1.7 million barrels per day confirming that the world's second largest oil field is in decline, joining the rank of Burgan (Kuwait) which also started declining in 2005.