‘We are at a tipping point’: Scientists warn Australia could see ‘human-level extinction’

A study of global warming models suggests Australia could witness a human-level tipping point as a result of global climate change, with a possible 50 per cent chance of a “global catastrophic” event.

The study by the US Geological Survey (USGS) and the University of Arizona’s School of Earth, Atmospheric and Planetary Sciences (SAPS) is the first to show the extent of an extreme temperature rise from CO2, which would result in “unprecedented” impacts across the globe.

The researchers, from the USGS, said the risk of such an event could be 50 percent if the average global temperature remained unchanged, and 50 percents if the global temperature rose by 2 degrees Celsius.

“It is very possible that we will see a global catastrophic event with a high probability of a global catastrophe,” said lead author Dr Paul A. O’Brien.

“We are looking at a global tipping point where we have a high risk of this happening.”

Dr O’Briens paper, published in the journal Nature Geoscience, used the USGSS Global Climate Model (GCM) and SAPS’ Global Temperature Index (GTI) to project the warming potential of a 2.5C temperature rise.

“Our GCM simulations show that if we continue to increase greenhouse gases at the current rate of emissions, we will be on track to exceed the 1.5 C temperature rise threshold by the end of the century,” Dr O’Malley said.

“This means that we are going to see at least a 50 per-cent chance of some kind of a catastrophic event, which is a big deal.”

Dr A.C. Wootton, a climate scientist from the University in Sydney and the lead author of the paper, said it was possible Australia could be in the danger zone.

“What we are talking about is the likelihood of a large-scale global catastrophic warming event that would have catastrophic consequences for the world,” he said.

Dr Wootons modelling showed that a 1.8C global temperature rise would be more than twice as likely to result in an extreme event, compared to a 1C increase of CO2.

“The probability of this is almost half,” Dr Woottons co-author, Professor John R. Hargreaves, said.

“It’s going to be pretty high, we’re talking about almost one in five.”

Dr Hargresons modelling was based on a combination of a number of different factors including greenhouse gas emissions and temperature variations in the atmosphere.

Dr Haskett, a former UN climate change expert, said while the potential for catastrophic climate change was great, it was still a long way off.

“In a nutshell, we are at this tipping point and we are not at the tipping point yet,” Dr Haskets said.

The paper was co-authored by Dr Paul O’Neill, from NASA’s Goddard Institute for Space Studies (GISS), and Dr Paul H. A. Atherton from the Centre for Climate and Energy Economics and Policy at the University the University at Albany.