Australia's climate is warming at an alarming rate and oceans around the continent have been rising by as much as a centimetre a year, according to a new government report
A dust storm hits Bondi Beach back in 2009. According to the report Australia has recorded its 13 hottest years on record since 1997. Photo: EPA
The snapshot, produced by the national science and weather agencies, found climate changes have been occurring at an increasingly rapid pace. It predicts fiercer storms, increased drought and more intensive periods of rainfall over the coming decades.
According to the report, based on observations and peer-reviewed research by government scientists, Australia has recorded its 13 hottest years on record since 1997 – and average day and night-time temperatures are now almost a degree higher than they were a century ago. Sea-surface temperatures increased by about 0.8C since 1910 and hit a record high in 2010. Each decade in Australia has been warmer than the previous decade since the 1950s.
The report, by the Bureau of Meteorology and the Commonwealth Scientific and Industrial Research Organisation [CSIRO], says the changes appear to have been mostly caused by human-induced carbon emissions and are not due to nature alone. Following a dip in carbon emissions during the financial crisis, carbon dioxide levels in the atmosphere reached 390 parts per million last year, the highest level in 800,000 years.
"It is very likely (at least 90 per cent likelihood) that most of the observed global warming since the mid-20th century is due to increases in greenhouse gases from human activities," the report says.
"Human activities also have influenced ocean warming, sea-level rise, and temperature extremes. It is very unlikely (less than ten per cent likelihood) that 20th century warming can be explained by natural variability alone."
Australia has been particularly hard-hit by global warming, with sea levels and ocean temperatures around the continent rising faster than world averages.
In the past 18 months, Australia has endured two La Ninas – leading to the nation recording its wettest two-year period since instrumental records began in the 1880s. The rainfall led to flooding in Queensland last year that killed dozens of people and caused damage to farms, houses and business of about $AUS30 billion.
Heavy rainfall over the recent summer has caused further bouts of heavy flooding across vast swathes of territory in New South Wales, Victoria and Queensland. This led to the highest two-year average rainfall on record.
Despite the recent cooler, rain-inducing La Nina weather pattern, increasing greenhouse gas concentrations are expected to lead to hotter weather in the coming decades. The report says average temperatures could rise by up to 5C by 2070.
"Global changes of this magnitude happen very rarely," said Karl Braganza, the head of climate monitoring at the Bureau of Meteorology.
"They happen when asteroids strike, they happen when there's planetary volcanic activity. They are happening now because we are digging up fossil fuels and basically burning them all. And we are doing that very, very rapidly."
The snapshot comes months before Australia's controversial tax on carbon emissions by heavy polluters comes into effect on July 1. The scheme will impose a tax of $AUS23 per ton on emissions and will be the world's biggest carbon reduction scheme outside Europe.