AN international study involving ANU has designed a simple climate model that gives authorities a more precise picture of how to avoid dangerous global warming this century.
The Paris Climate Agreement set targets to restrict the rise in global temperatures to two degrees Celsius or less above pre-industrial levels by reducing carbon emissions.
Co-researcher Prof Eelco Rohling from ANU says the uncertainties in climate models used by scientists today were too large to develop future carbon budgets that meet specific warming targets.
“There is significant uncertainty in projecting the amount of carbon that can be emitted, in part due to the limited number of earth system model simulations and their discrepancies with present-day observations,” says Prof Rohling.
“Our model narrows the uncertainty in global warming projections and reduces the range in equilibrium sensitivity of global temperatures to emissions.”
Prof Rohling says a warming target of 1.5 degrees above the pre-industrial level would require the total emitted carbon from the start of last year to be less than 195–205 petagrams of carbon – a petagram is one billion metric tonnes.
“The two degree target is only likely if the emitted carbon remains less than 395 to 455 petagrams of carbon,” Prof Rohling says.
“At the current emission rates, the 1.5 degree target is reached in 17 or 18 years and the two degree target in 35 to 41 years, so there is a limited window to develop a low carbon future.
“Immediate action on climate change is essential, to develop strategies towards zero carbon emissions, options to take carbon out of the atmosphere and ways to adapt to the effects of a much warmer climate.”
ANU conducted the study in collaboration with the University of Southampton and the University of Liverpool in the United Kingdom.
The study is published in “Nature Geoscience”.