Business Green: Climate scientists gathering in Copenhagen today attempted to hammer home the full scale of the threat posed by global warming, warning that we are currently on track for a “five-degree world” where the global population would be slashed from an expected nine billion in 2050 to just one billion people by the end of the century. Opening the final day of the Climate Congress meeting was Professor John Schellnuber of the Potsdam Institute for Climate Impact Research and one of the …