John Howard's coalition government was warming to an emissions trading scheme in the year 2000.
Twenty-year-old cabinet papers - released by the National Archives of Australia - reveal a government on a trajectory towards an ETS, with the Australian Greenhouse Office commissioned to conduct a feasibility study.
Then-environment minister Robert Hill backed a market-based approach, noting in a submission to cabinet that environmental issues had a high public profile.
The policy was in line with the coalition's market-oriented economic philosophy, encouraged by its success in introducing the goods and services tax.
Senator Hill told cabinet he was developing a new initiative designed to encourage businesses to adopt environmentally-sensitive processes in their operations.
In the other corner sat industry and resources minister, Nick Minchin.
Cabinet papers show him in action championing, with then-treasurer Peter Costello, a liquefied natural gas plan.
Senator Minchin argued that future greenhouse gas abatement action should not render Australian industries, including LNG, uncompetitive.
But he acknowledged market-based mechanisms were the most efficient and least costly means of achieving Australia's greenhouse gas targets.
In August 2003, Mr Costello took a proposed cap and trade ETS to cabinet, where it was rejected, reportedly following industry lobbying of Mr Howard.
The prime minister may not then have been convinced of the merits of an ETS but that changed and in June 2007, he announced a scheme was government policy and would be in place by 2012.
Archives consultant historian Christine Wallace said this was one of the great "what ifs" of recent Australian political history.
"What if Howard had won the 2007 election? What if Costello had succeeded Howard prior to the 2007 election and gone on to win it?" She asked.
"Both had committed to an ETS. Both were practised in initiating, marketing and implementing a new tax, as they showed so capably with the GST.
"Had either of these counterfactual scenarios actually come about, an ETS might already have been operating in Australia for years - an accepted, unremarked-upon aspect of public finance in Australia, just like the once-controversial GST."
As it turned out, Labor won the 2007 election.
Kevin Rudd declared climate change one of the great moral, economic and environmental challenges. But efforts to legislate an ETS got bogged down.
It was left to new Labor PM Julia Gillard to introduce a carbon price, against which opposition leader Tony Abbott campaigned vigorously, terming it "the great big tax on everything".
Mr Abbott set about dismantling Labor's climate policies upon winning government in 2013.
Back in 2000, the coalition was at best green in part.
Although Australia had signed the 1998 Kyoto Protocol on emissions, Mr Howard declined to ratify it on grounds that it would disadvantage Australia.
Interestingly, Senator Hill sought to make approval for the Kogan Creek coal-fired power station conditional on "the difference in greenhouse gas emissions between it and an equivalent gas-fired power station be fully offset by investment in sinks."
The environment department's submission noted that the combined emissions of Kogan and an alumina project would account for a quarter of all future emissions growth Australia was permitted under Kyoto.