Australia's carbon pollution would increase by at least nine percent by 2020 under the policies of the conservative opposition, breaching global commitments, new pre-election modelling showed on Thursday.
The modelling, published by Australia's independent Climate Institute thinktank, showed that "under all (opposition) coalition scenarios Australia's emissions continue to increase to 2020 and beyond".
"Even with conservative assumptions, the coalition's policy as it is currently defined would see Australia's emissions rise about nine percent by 2020," said Climate Institute chief executive John Connor.
According to the modelling, which examined a range of pledges and policies from Tony Abbott's opposition—currently on track to win the September 7 election according to opinion polls—emissions would increase by between eight and 10 percent from 2000 levels by 2020.
"This is the equivalent of doubling Australia's car fleet over this period," the Climate Institute report said.
Both Abbott and the ruling Labor party have committed to global emissions reduction targets of at least five percent from 2000 levels by 2020.
Labor plans to achieve this through an emissions trading scheme to replace its current pollution tax on major emitters; the opposition has a "direct action" plan including an emissions reduction fund to encourage business and industry efforts.
A controversial scheme to sequester carbon dioxide in soil—criticised as technically limited and economically unviable by experts—is the other major plank of its policy.
The Climate Institute said Abbott would need to spend an extra Aus$4-15 billion (US$3.6-13.7 billion) on top of current pledges to meet the five percent reduction target by 2020, and his emissions reduction fund would effectively subsidise "business as usual" pollution at current levels.
The modelling showed that conservative policies would reduce Australia's domestic emissions by 200 million tonnes by 2020, compared with 290 million tonnes under Labor.
"As a country highly vulnerable to the impacts of climate change, it's in our own interest for the world to limit temperature rise to less than two degrees above pre-industrial levels," Connor said.
"The next couple of years are crucial in helping boost global efforts."
Abbott rejected the report, saying his environment spokesman Greg Hunt was "absolutely confident that we can purchase sufficient emisisons reductions from the funding envelope that we've made available".
"People have a right to put forward a position, the Climate Institute is obviously entitled to put forward its position, but I simply don't accept that report," he said.
Abbott said Labor would only meet its 2020 commitment by purchasing Aus$3.5 billion in carbon credits on the international market.
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