About 150 turns out from 2050AD decided I wanted my Persian empire to go down in history with a much grander score, so I decided to conquer my neighbors. I swallowed Egypt, and then Germany, and then turned my appetite to Mongolia. Halfway into my war with Ghengis Khan the oddest thing happens...Global Warming strikes Alexandria. This isn't like Civ3 Global Warming either. The tile was a grassland with a Town on it....and now it is desert. Following that disaster, global warming struck random cities in my empire about once every 4 turns..and in one case it struck two tiles for two respective cities in the same turn. I can find no reference to Global Warming at all in the Civilopedia and was under the impression they took it out of Civ4. Much to my dismay, not only is included in Civ4, they have suped it up! Anyone have information on this? is it a result of me conquering so many cities that had their city improvements destroyed? Is there any way to turn off this 'feature'?