By James Whitmore, The Conversation
2014 has been confirmed as Australia’s third-hottest year, capping off a record-breaking decade, according to the Bureau of Meteorology’s annual climate statement, released today.
Seven of Australia’s ten hottest years have occurred in the past 13 years. During that period, only 2011 was cooler than the 1961-1990 average. Experts said this long-term trend and temperature extremes are a clear signal that climate change is happening in Australia now.
“If we want to look at the impact of climate change, what we’re really seeing is the climate of Australia has continued to warm,” said Karl Braganza, manager of Climate Modelling at the Bureau of Meteorology.
In the ten years to 2014, temperatures have been running 0.55C above the long-term average. The previous ten-year record was held by 2004-2013 at 0.5C above average.
The two-year period of 2012-2013 also smashed the previous 24-month record by 0.32C.
2014 on its own was the third-hottest year since Australia’s official records began in 1910, with temperatures 0.91C above average. This followed Australia’s hottest ever year, with temperatures 1.2C above average.
2014 also set a new record for the hottest spring, breaking the previous record set the year before.
Sophie Lewis, a climate scientist at the Australian National University, said these extremes were “at least 30 times more likely because of human influences, such as greenhouse gases”.
Globally, 2014 is likely to have been the hottest on record, driven by record-breaking sea surface temperatures. The UK Met Office also recorded 2014 as the UK’s hottest year.
Sarah Perkins, a climate researcher at the University of New South Wales, said that while 2014 was not Australia’s hottest, the year included significant hot periods, including the “infamous” Australian Open heatwave. The record-breaking spring contributed to another early start to the bushfire season, and recent heatwaves increased the bushfire risk and poor fire-fighting conditions currently in South Australia, she said.
Lower rainfall linked to El Niño conditions was driving warmer temperatures over the last six months, Braganza said. Models suggest El Niño could persist into 2015, potentially making 2015 as warm or warmer than 2014.
Braganza also said there has been a “notable absence” of cold weather.
“We’ve had heatwaves consistently every six weeks or over the past two or three years, even throughout winter.
“Since the mid-20th century, the spatial extent of these heat events has been growing. Heatwaves are becoming more frequent, they’re becoming hotter, lasting longer, and covering more of the continent.”
Comments compiled with the help of the Australian Science Media Centre.