Guardian: Coral growth across the Great Barrier Reef has suffered a “severe and sudden” slowdown since 1990 that is unprecedented in the last four centuries, according to scientists. The researchers analysed the growth rates of 328 coral colonies on 69 individual reefs that make up the 1,250 mile-long Great Barrier Reef, off north-east Australia. They found that the rate at which the corals were laying down calcium in their skeletons dropped by 14.2% between 1990 and 2005. Corals around …