Ms Price, who is attending the summit in the city of Katowice, has put the expected surplus by 2020 - when the Paris agreement kicks in - at 294 million tonnes of carbon dioxide-equivalent. However, consultancy Climate Analytics calculated the final figure will be at least 333 million tonnes. If accounting around land use changes - including tree planting and land clearing - is settled in Australia's favour, the surplus could swell to 400 million tonnes. Australia's current pledge under the Paris agreement is to cut emissions 26-28 per cent below 2005 levels by the year 2030. Unless other nations object to the use of carryover credits, it could then meet the target with just a 15 per cent cut - a much easier task. "This appears to be the 'canter' the government keeps talking about," said Bill Hare, director of Climate Analytics. "It is fake action and would be rorting the planet, and will undermine real action in Australia."

Carryover estimates are based on data provided by Australia to the UN Framework Convention on Climate Change (UNFCCC) at the end of 2017. Loading Ms Price declined to directly answer questions about how it will use any Kyoto carryover. "The government is interested in working with international partners in the development of our strategy, through consultations with G20 countries that have completed their strategies or those currently in [a] planning or development phase," said Ms Price.

A spokespeson for the Environment Department reiterated that the projected 2013-2020 "over-achievement" was at 294 million tonnes, but added that emissions projections for 2018 were "currently under preparation". "The Australian government is committed to the Paris Agreement," the spokesperson said. "Our priority at [Katowice] is to secure agreement on a comprehensive Rulebook to guide the implementation [of the Paris pact]. 'Fatal undermining' Richie Merzian, who was part of Australia's climate negotiations team for nine years before joining think tank The Australia Institute in April, said the government had long considered deploying a Kyoto surplus towards its Paris target. "It was certainly part of their train of thinking," Mr Merzian said. "It could be they were banking on this."

"You're basically getting away without reducing your emissions," he said. Use of any credits would be consistent with Australia's past approach of booking any "over-achievement" towards its next emissions goal. Germany, the UK and three other European nations cancelled 635 million tonnes of credits from the first Kyoto period at the Paris talks in 2015 but Australia kept its 128 million-tonne surplus. Mr Hare said while the Polish talks may not rule directly on the carryover issue, backroom debate would no doubt include the issue given its importance. New Zealand is among others facing similar decisions to Australia's. "It is no exaggeration to suggest that if this approach is allowed it would lead ultimately lead to a fatal undermining of any integrity in accounting for the implementation of the Paris Agreement," he said. "There would be little recourse against others opening up loopholes." Most of Australia's emissions reductions in the past couple of decades have stemmed from tighter restrictions in Queensland that curbed deforestation after 2006.

Activists dressed in polar bear costumes protest on the sidelines of the COP24 climate talks now taking place in the Polish city of Katowice. Credit:AP Labor caution Mark Butler, Labor's climate spokesman, declined to rule out using Kyoto credits if the ALP wins office next year. "Labor will take advice from relevant agencies and experts," he told the Herald. Labor has pledged to lift Australia's current Paris pledge to a 45 per cent economy-wide reduction from 2005-level emissions by 2030.

"Regardless of how Kyoto units are treated in future, Australia has to take strong action to cut pollution and transition our economy to clean energy," Mr Butler said. Adam Bandt, the Greens' climate spokesman, said the public expected “a government of climate deniers to use dodgy accounting to shirk their climate responsibilities, but not Labor". “Labor needs to follow the lead of many other developed countries and immediately rule out using carryover credits to meet our measly Paris obligations if it wins office," he said. Emma Herd, chief executive of the Investor Group on Climate Change, said any weakening of emissions targets would sap investments needed to tranform the economy to net-zero emissions by mid-century. "To secure the long-term prosperity of Australia, targets need to be in line with the objectives of the Paris Agreement - limiting warming to 1.5 degrees and well below 2 degrees," Ms Herd said.