Do the Suez and Panama canals have any impact on world temperature and weather cycles?
Good question, but a bit misleading. As alluded to in previous answers, the Panama canal is fed by fresh water, and there is no possible movement of sea water as the canal rises some sifnificant way above sea level. Before the isthmus, the expanse of sea free to move was vast. These two cannot be compared. In the case of the Suez, the linked seas are relatively enclosed and there is limited movement of water between them and the open oceans. Although it is at sea level, the quantity of water moving through is minimal thus the effect of water itself is negligable. Also as the water temperature is similar, that has no effect either. So, no, I very much doubt it at a local level, let alone at a global one. And the only impact on global warming is from the sea traffic using them (though remember that will be less than if they had to make the alternative detour – so the canals in effect reduce the contribution to global warming!
