The year 2015 saw the hottest temperature on record globally but in less than a decade, this may just be another year. A research published by the Bulletin of American Meteorological Society reveals that human activities had already locked in a "new normal" for global average temperatures that would occur no later than 2040.
Lead author Dr. Sophie Lewis from the Australian National University hub of the ARC Centre of Excellence for Climate System Science stated, "If we continue with business-as-usual emissions, extreme seasons will inevitably become the norm within decades and Australia will be the canary in the coal mine that will experience this change first."
But Dr. Lewis doesn't think the situation is completely without hope. Though annual global average temperatures were locked in, it would still be possible with immediate and strong action on controlling carbon emissions to prevent record-breaking seasons from becoming average, at least at regional levels. "If we reduce emissions drastically to the lowest pathway recommended by the Intergovernmental Panel on Climate Change, then we will never enter a new normal state for extreme seasons at a regional level in the 21st Century," Dr. Lewis said.
Dr. Lewis and her colleagues have now developed a scientific definition for the term 'new normal' as this is the cornerstone of their new research. "Based on a specific starting point, we determined a new normal occurred when at least half of the years following a record year were cooler and half warmer. Only then can a new normal state be declared," she said.
The researchers, in an effort to determine when new normal states would appear under the Intergovernmental Panel for Climate Change's four emissions pathways, used the National Computational Infrastructure supercomputer at Australian National University to run climate models. Results showed that though global average temperatures would inevitably enter a new normal under all emissions scenarios, this wasn't the case at seasonal and regional levels.
"It gives us hope to know that if we act quickly to reduce greenhouse gases, seasonal extremes might never enter a new normal state in the 21st Century at regional levels for the Southern Hemisphere summer and Northern Hemisphere winter," Dr Lewis stated.