Canal De Panamá, Panama

The increasing rate of melting of ice in the Arctic Ocean has led to speculation that the Northwest Passage or Arctic Bridge may become viable for commercial shipping at some point in the future. This route would save 9,300 km (5,800 mi) on the route from Asia to Europe compared with the Panama Canal, possibly leading to a diversion of some traffic to that route. However, such a route is beset by unresolved territorial issues and would still hold significant problems owing to ice.
Water issues
Gatun Lake is filled with rainwater, and the lake accumulates excess water during wet months. The water is lost to the oceans at a rate of 101,000 m3 (26,700,000 US gal; 22,200,000 imp gal) per downward lock cycle. Since a ship will have to go upward to Gatun Lake first and then descend, a single passing will cost double the amount; but the same waterflow cycle can be used for another ship passing in the opposite direction. The ship's submerged volume is not relevant to this amount of water. During the dry season, when there is less rainfall, there is also a shortfall of water in Gatun Lake.