There's a rogue engineer on the loose / How much would it cost to save all endangered animals on earth? / Tepco admits responsibility for Fukushima meltdowns / Tanzania applies for permission to sell ivory stockpile / Saudi Arabia plans to go green / Russia to salvage two sunken nuclear subs / Why a four-day week could be good for you and the environment   (Photo: penelope Clay)

Businessman Russ George defends experiment seeding Pacific with iron sulphate

Guardian: World's biggest geoengineering experiment 'violates' UN rules