National Geographic: Fossil coral reefs at a Mexican theme park “confirm” that sea levels rose rapidly about 121,000 years ago, according to a controversial new study. Previous research on fossil reefs had shown that sea levels surged by 13 to 19 feet (4 to 6 meters) near the end of the last time period between ice ages, known as an interglacial period. But researchers have been unsure whether this sea-level rise happened quickly or gradually. By mapping the ages and locations of ancient corals at …