Act now or 'hottest year' may become new normal by 2040, warns study

According to researchers, no matter what action we take, human activities have already locked in a 'new normal' for global average temperature

The year 2015, which is on record the hottest year globally, could become the new normal by 2040 if carbon emissions continue to rise at the current rate, researchers have warned.

However, with immediate and strong action on carbon emissions, it is still possible to prevent record-breaking seasons from becoming the new average — at least at regional levels, the study said.

Only days ago, the historic Paris Agreement came into force, which aims to limit global warming to well below 2 degrees Celsius and as close to 1.5 degrees Celsius as possible to prevent dangerous tipping points in the climate system.

As of now, the Paris Climate Change Agreement has been joined by only 97 countries, including India, accounting for just over two-thirds of the world's greenhouse gas emissions.

According to lead author Sophie Lewis from the Australian National University (ANU), no matter what action we take, human activities have already locked in a "new normal" for global average temperatures that would occur not later than 2040.

"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," Lewis added.

For the study, using the National Computational Infrastructure supercomputer at ANU to run climate models, the researchers explored when new normal states would appear under the Intergovernmental Panel for Climate Change's four emissions pathways.

The ANU study coincides with the UN climate change conference in Marrakech, the first meeting of the Paris Agreement's governing body.

The Marrakech conference gives developed countries the opportunity to present their roadmap to mobilise the pledged $100 billion in annual support to developing countries by 2020.

The team of researchers also examined seasonal temperatures from December to February across Australia, Europe, Asia, and North America.

The results revealed that while global average temperatures would inevitably enter a new normal under all emissions scenarios, this was not the case at seasonal and regional levels.

"It gives us hope to know that if we act quickly to reduce greenhouse gasses, 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," Lewis said, in the paper published in the Bulletin of American Meteorological Society.