SciDev.Net: World leaders must reduce the long-held target of limiting global warming to below two degrees Celsius to avoid catastrophic impacts on the world's poorest people, says a leading climate scientist. Industrialised nations must stop ignoring the sustained calls from the developing world - backed by scientists - and set a 1.5 degree cap when the internationally agreed limit comes under review at UN climate talks later this year in Paris, France, says Petra Tschakert, a geographer from Pennsylvania...