Guardian: A vast swath of the coastal lands around New Orleans will be underwater by the dawn of the next century because the rate of sediment deposit in the Mississippi delta can not keep up with rising sea levels, according to a study published today. Between 10,000 and 13,500 square kilometres of coastal lands will drown due to rising sea levels and subsidence by 2100, a far greater loss than previous estimates. For New Orleans, and other low-lying areas of Louisiana whose …