NY Times articles
here.

The savage heat waves that struck Australia in 2013 were almost
certainly a direct consequence of the human release of greenhouse gases,
researchers said Monday. It is perhaps the most definitive statement climate
scientists have made that ties a specific weather event to global warming.

Five groups of researchers, using distinct methods, analyzed the heat that baked
Australia for much of last year and continued into 2014, shutting down the
Australian Open tennis tournament at one point in January. All five came to the
conclusion that last year’s heat waves could not have been as severe without the
long-term climatic warming caused by human activity.

“When we look at the heat across the whole of Australia and the whole 12 months
of 2013, we can say that this was virtually impossible without climate change,”
said David Karoly, a climate scientist at the University of Melbourne who led
one research team.