In a time of rising seas and intensifying storms, one of the world’s wealthiest, most-educated cities made a fateful decision to spend billions of dollars erecting a new district along its coast — on landfill, at sea level. Unlike other places imperiled by climate change, this neighborhood of glass towers housing some of the world’s largest companies was built well after scientists began warning of the threats, including many at its renowned universities. The city, which already has more high-tide flooding than nearly any other in the United States, called its new quarter the Innovation District. But with seas rising inexorably, and at an accelerating rate, others are calling the neighborhood by a different name: Inundation District.