A new study in Australia has revealed that temperatures in 2015 - the hottest year on record - might become the new normal by 2025 if carbon emission levels continue to rise at their current rate.
Researchers from the Arc Centre of Excellence for Climate System Science found that human activities have already set a new normal for average global temperatures that would occur no later than 2040.
Sophie Lewis, lead author of the study, said if the business-as-usual emissions continue, extreme seasons will become the norm within the next decades.
However, Lewis says there is still hope: immediate and urgent climate action could prevent record-breaking seasons from becoming average year by year, at least at regional levels.Extreme Temperatures In Australia
Lewis, who is a climate scientist from the Australian National University, says Australia might experience the extreme changes in temperature first.
If carbon emission rates are not reduced, the record hot summer of 2013 in Australia - when temperatures approached almost 50 degrees Celsius (122 degrees Fahrenheit) - could become just another average summer by 2035, Lewis said.
"The likely impacts of an extremely hot year in 2035 would be unlike anything we have ever experienced," said Lewis.The 'New Normal'
The concept of a "new normal" has been repeatedly discussed when it comes to climate change, but it has not been clearly defined until ANU researchers developed a scientific definition for the term.
Researchers determined that a new normal occurs when at least half of the years that follow an extreme year were cooler and half warmer, depending on a specific starting point.
This same process was also used to determine new normal conditions for regional and seasonal changes to the climate, the study said.Seasonal And Regional Levels
With the help of the National Computational Infrastructure supercomputer at the university, Lewis and colleagues explored when states of new normal would manifest under the four emission pathways of the Intergovernmental Panel for Climate Change.
Lewis and colleagues analyzed seasonal temperatures from December to February across Australia, Asia, North America and Europe.
Results showed that while the average global temperatures would inevitably reach a new normal under all possible emission scenarios, this would not happen at regional and seasonal levels.
Lewis said this offers hope that if we act immediately to curb the emission of greenhouse gases, extreme seasonal temperatures might never reach a state of new normal at the regional level for the Northern Hemisphere winter and the Southern Hemisphere summer.
Details of the new study are published in the Bulletin of the American Meteorological Society.