Bloomberg: Carbon permits will rise more than 18-fold to $400 a metric ton by 2050 unless spending on new technologies that curb emissions is increased, the Organization for Economic Cooperation and Development forecast. Carbon prices may be held to about $200 a ton if there’s more spending on developing technology such as hydrogen fuel- cell vehicles over the next decade, Romain Duval, a senior OECD economist, said last week in an interview in Poznan, Poland. “The big difference is you …