The savage heat waves that struck Australia last year were almost certainly a direct consequence of greenhouse gases released by human activity, researchers said Monday. It is perhaps the most definitive statement climate scientists have made tying a specific weather event to global warming.

Five groups of researchers, using distinct methods, analyzed the heat that baked Australia for much of 2013 and continued into 2014, briefly shutting down the Australian Open tennis tournament in January when the temperature climbed to 111 degrees Fahrenheit.

All five research groups 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 emissions.

“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 some of the research.