Sunset Credit : NOAA (CC BY 2.0)
Original Published Date: 
Tuesday, July 21, 2020

Full article issued by The ARC Centre of Excellence for Climate Extremes and The University of New South Wales.

An international research team led by Australian Laureate Fellow Professor Steven Sherwood, based at the ARC Centre of Excellence for Climate Extremes, and including former Australian Laureate Fellow Professor Eelco Rohling, has conducted the most advanced and comprehensive analysis of climate sensitivity yet undertaken, to reveal with more confidence than ever before how sensitive the Earth’s climate is to carbon dioxide. 

For more than 40 years, the estimated likely range of the eventual global temperature response to a doubling of atmospheric carbon dioxide compared to preindustrial levels has stubbornly remained at 1.5°C – 4.5°C. 

This new research, revealed in a 165 page, peer-reviewed journal article commissioned by the World Climate Research Programme written over four years, finds that the true climate sensitivity is unlikely to be in the lowest part of the 1.5-4.5°C range.

The analysis indicates that if atmospheric carbon dioxide levels double from their pre-industrial levels and are maintained, the world would probably experience eventual warming from 2.3 – 4.5°C. The researchers found there would be less than 5% chance of staying below 2°C and a 6-18% chance of exceeding 4.5°C.

With the Earth’s temperature already at around 1.2°C above preindustrial levels, if greenhouse gas emissions trajectories continue unabated the world can expect to see a doubling of carbon dioxide in the next 60-80 years.

The research was only made possible by bringing together the international team of researchers from a wide range of climate disciplines. Using temperature records since the industrial revolution, paleoclimate records to estimate prehistoric temperatures, satellite observations and detailed models that examine the physics of interactions within the climate system the team were able to combine more independent lines of evidence than any previous study to get their results.

Photo credit: 

Credit: NOAA (CC BY 2.0).