"It means we are essentially passing one in a whole series of points of no return, " said Michael Mann, a climate scientist at Pennsylvania State University.

NPR: Experts: CO2 Record Illustrates 'Scary' Trend

Yesterday the Dow dropped almost 400 points as Italian bond yields surged past the 7% mark that is seen as the point of no return.

FORBES: Rebound In Stocks With Italian Bond Yields Dipping Below 7% Crisis Level

The Springboks, meanwhile, return home with no points from their three away matches, with next to no hope of defending their title after suffering a third straight defeat for the first time since 2007.

BBC: Australia 30-13 South Africa