The record-breaking heat seen across southeast Australia in the last few months was made 50 times more likely by climate change, according to new analysis that links the heat directly to global warming.
Southeast Australia was struck by three major heatwaves in January and February, with temperatures climbing as high as 113°F (45°C) in some places. On February 10, Sydney Airport recorded its hottest February day on record, with temperatures hitting 109°F (42°C). The heat was also uncharacteristically persistent — Observatory Hill in Sydney saw temperatures reach above 95°F (35°C) for nine consecutive days in January, breaking a 120-year old record. Elsewhere, the consistent heat was even more extreme: in Moore, New South Wales, there were 52 consecutive days with temperatures above 95°F (35°C).
The study, conducted by the World Weather Attribution Program at Climate Central, used climate model simulations and observational data analysis to understand how climate change, caused by an increase in greenhouse gases in the atmosphere, might have made these heat events more likely. They found that climate change made the average temperatures seen this summer in Australia 50 times more likely, and made the maximum summer temperatures 10 times more likely.
“In the past, a summer as hot as 2016–2017 was a roughly 1 in 500-year event,” the researchers wrote. “Today, climate change has increased the odds to roughly 1 in 50 years — a 10-fold increase in frequency.”
The analysis also warns that heat events like these — both punctuated heatwaves and long stretches of above-average temperatures — are likely to become more frequent as climate change continues. In the future, according to the study, heat events like the one this summer could happen as frequently as every five years — and will likely be more intense, with temperatures averaging at least 1.8ºF (1°C) warmer than they were in the past.
The connection between heat waves and climate change has strong scientific support. In 2015, eight papers published in the Bulletin of the American Meteorological Society’s attribution report — an annual report that explains extreme weather events from a climate perspective — all linked climate change to heatwaves, showing that climate change clearly made heatwaves either more likely, more intense, or both.
According to data from NASA and NOAA, 2016 was the hottest year on record. Before that, both 2015 and 2014 held that distinction. In fact, 16 of the 17 hottest years on record have occurred since 2001.