Scientists are 90 percent sure this year's Australian heat wave couldn't have happened without manmade influence. Photo: CIA
Surprise, surprise: The record-breaking heat wave that plagued Australia earlier this year with temperatures that reached up to 121 degrees was almost certainly caused by humans, according to a new study.
The study, published in Geophysical Research Letters by scientists at the University of Melbourne and Australia's ARC Centre of Excellence for Climate Systems Science, highlights how humans have heightened drought effects on the continent. According to the authors, "human contribution to the increased odds of Australian summer extremes like 2013 was substantial, while natural climate variations alone, including El Niño Southern Oscillation, are unlikely to explain the record temperature."
The so-called "angry summer" was easily the hottest on record, with temperatures hitting more than 27 degrees above average in some parts of the country during the first week of January. When it was happening, meteorologists with the Australian government said that though "Australia has always experienced heat waves … the event affecting much of inland Australia has definitely not been typical."
Temperatures hit up to 121 degrees F in parts of Australia in January. Photo: Australian Government Bureau of Meteorology
That's for sure: According to Sophie Lewis, one of the authors of the latest study, using nine of the most cutting edge climate models, the probability that increased greenhouse gases were at least partially to blame for the heat wave is more than 90 percent.
"We compared temperature probabilities in a suite of model simulations of the climate including only natural climate influences (volcanoes and solar radiation changes) with a parallel set of model simulations including natural and anthropogenic climate influences, such as greenhouse gases," Lewis said. "The results were clear - when [man made] influences were included in the model simulations, the probability of warmer summer temperatures like 2013 were far higher. It was very likely that human influences increased the odds of summer extremes by at least five times."
You've heard this all before, but with us busting through the 400 PPM carbon dioxide threshold, this is probably the new norm, Lewis said.
"The model experiments also show that these types of extreme Australian summers will become more severe and more frequent in the future, with further global warming," she said. "Extreme summers occur 8 times more frequently in the climate model simulations that include human influences, such as greenhouse gases, compared to the climate model simulations with only natural climate variations."
Let's see if we can break 125 degrees next year.