"However, until confirmed, the reason those primitive arcologies are believed to have failed is thermal inversion. There are rivers of water running through the ocean, some hot, some cold. They shift about and move freely, so there can be a dynamic difference of twenty degrees in ocean water within a mere ten meters. For a dometown a thousand meters tall, the differences can be incredible, and deadly. Mini-fissures are created by the temperature differences. These lead to a general weakening, then cracks and explosive decompression and total dome failure. Millions, and in some cases, billions lost in an eyeblink."