However, article two of the agreement locks signatories into following the “best available science” on the required “rapid reduction” of emissions, and the “highest level of ambition”, to limit global warming to below two degrees and as close to 1.5 degrees as possible. Macquarie University Deputy Vice-Chancellor Lesley Hughes said the science showed that under the current trajectory of warming, net zero global emissions before 2050 would be required to limit the temperature rise to below two degrees. Loading Replay Replay video Play video Play video “Net zero is absolutely necessary, but the bigger question is how quickly we get there, and what are the interim targets? If we are emitting like we are now and then suddenly hit net zero in 2050, we would overshoot the target by two degrees,” Professor Hughes said. “The emissions plan and trajectory of emissions reduction over the next decade will count more to global warming than what happens in 2040 to 2050.”

Loading The Morrison government has committed to achieve an interim target under the Paris Agreement to reduce the country’s emissions by 26 to 28 per cent on 2005 levels by 2030. It will likely use “carryover credits” gained by exceeding the Kyoto climate agreement to meet about half the emissions reduction required under Paris. Labor said it would meet the 2030 goal without carryover credits, but has not detailed how quickly it would reduce emissions to zero between 2030 and 2050. Australian National University Emeritus Professor Will Steffen said the 28 per cent emissions reduction target was “too little, too late” in light of what the science said was required to limit warming to under two degrees. “In 2015, the Climate Change Authority found that to meet the Paris Agreement, Australia would need to reduce emissions by 40 to 65 per cent by 2030, with no carryover credits,” Professor Steffen said.

Pep Canadell, a senior research scientist for CSIRO and the executive director of the Global Carbon Project, said to keep warming to as close to 1.5 degrees as possible would require “global carbon neutrality”, and warned Australia against leaving the bulk of emissions reductions to after 2030. “That would mean we have just 20 years to hit zero, and completely get rid of all fossil fuel electricity,” he said. Minerals Council of Australia chief executive Tania Constable said her organisation “firmly supports" the Paris Agreement, and it was developing a climate action plan on “how the mining industry can assist Australia meet its commitments”. The Australian Petroleum Production and Exploration Association also endorses the Paris Agreement and chief executive Andrew McConville pointed out “a number of our member companies already support net zero emissions by 2050”. Australian gas giants Woodside and Santos, as well as multinational resources companies Shell, Chevron and BHP Billiton, back the Paris Agreement and promote their aspiration to be carbon neutral by 2050.