It's taken until very late in the campaign, but the Coalition's climate policy fig leaf has finally fallen off.

For years now, the Coalition has tried to convince voters that its “Direct Action” policy would be able to achieve a 5 per cent reduction in carbon emissions – the same environmental outcome as Labor's carbon tax, but without the dreaded tax.

Of course, Direct Action was always basically bullshit, in the very specific meaning of that term advanced by philosopher Harry Frankfurt. Frankfurt's point was that a lie is a conscious intention to deceive. Bullshit, on the other hand, is not really about truth or falsehood, but about providing cover while advancing some particular interest.

Direct Action is a perfect example of this. The goal of the policy wasn't to fool voters into believing the Coalition could deliver meaningful action on climate change. After all, many Coalition voters don't believe in climate change in the first place. Its real aim was to obfuscate and misdirect, in order to provide an intellectual smokescreen for the Coalition's relentless assault on Labor's carbon tax. That's why the dubious and untested science of soil carbon, which lies at the centre of Direct Action, was so useful. Soil carbon could work. Or maybe it won't. I don't think Greg Hunt and Tony Abbott really care.

It's basically impossible to find an independent analyst who believes Direct Action can work. On the other hand, as Labor's Mark Butler has noted, there is an avalanche of evidence that shows it will fail. If we take just the example of soil carbon, the University of Western Australia estimates it will cost farmers something like $80 per tonne of sequestered carbon to implement. The CSIRO's Michael Battaglia has made a similar argument – that carbon farming is highly sensitive to carbon prices, as well as interest rates and the stability of future carbon legislation.

Independent modelling by SKM–MMA – a firm best known for its work for the fossil fuel industry – suggests that Direct Action will most likely result in a 9 per cent increase in carbon emissions, and still cost billions more than the Coalition has budgeted.

Now we know the Coalition doesn't really believe in Direct Action either. On Monday Tony Abbott revealed he wouldn't be too concerned about whether Australia met its 5 per cent emissions reduction target by 2020. Speaking at the National Press Club, Abbott dropped any pretence of concern about the long-term consequences of climate change. Instead, he railed against the “almost unimaginable” economic impacts of a carbon price, and told journalists bluntly that the Coalition will be spending no more than it has budgeted on reducing carbon. If that doesn't produce a 5 per cent reduction, so be it.

“The bottom line is we will spend as much as we have budgeted, no more and and no less. We will get as much environmental improvement, as much emission reduction as we can for the spending we have budgeted,” Abbott said at the National Press Club. “We are very confident we can achieve the 5 per cent target … but in the end we have told you the money we will spend – and we won’t spend any more,” he said.

That's a massive backflip by any standards. Direct Action can't work, and Abbott has now admitted it. Really, it reveals that the Coalition has been misleading voters all along on climate. In a close campaign, such an admission might have been devastating.

The Coalition is so far ahead in the polls, and many sections of the media are so biased against the current government, that the stunning backflip generated little more than a ruffle from certain sections of the online media – led by Lenore Taylor at the Guardian and Tristan Edis at Climate Spectator. It was mentioned only in passing elsewhere.

Indeed, so confident is the Coalition of victory, Abbott has flicked the switch to incumbency this week, defining his own election mandate before even getting elected. On Tuesday he was telling the media that this election is a “referendum on the carbon tax”, and that if he did win, “the last thing the Labor Party will do is commit political suicide twice by continuing to support this absolutely toxic tax”. On Lateline last night, the Coalition's climate spokesman Greg Hunt was backing him up, again threatening a double dissolution election if Labor did not wave through the Coalition's plans to repeal the carbon tax.

Mandates are always a slippery concept in representative democracies, in which voters delegate governance to politicians and then trust them to do the things that they said they would. Both Labor and the Coalition went to the 2007 election, for instance, promising emissions trading schemes. That didn't stop the Liberals from dumping Malcolm Turnbull, installing Abbott, and then frustrating Labor's attempts to legislate exactly that policy. A bipartisan mandate meant nothing when it came to attacking Labor in government.

For a political animal like Tony Abbott, the significance of the m-word is not so much in winning Saturday's poll – Coalition strategists appear to believe they've got it in the bag – but in putting down markers for future battles. The Coalition would dearly love to use carbon as a club to beat Labor with mercilessly once in office. Claiming a mandate on carbon is a handy tactic that will allow Abbott and his cheerleaders in the Murdoch tabloids to argue that the question of carbon pricing has been settled, and that Labor is on the wrong side of history.

In fact, precisely the opposite is true. Carbon policy is not settled, and Labor is right to claim it will stick to its guns in opposition. Climate change is real and worsening, with the IPCC's Rajendra Pachauri recently telling the world we are at “five minutes to midnight” when it comes to saving the planet. An Australian government that walked away from its binding 5 per cent target on reducing emissions would be a huge symbolic blow to international action. In the meantime, the sophisticated infrastructure that Labor has painstakingly built on carbon – the Climate Commission, the Australian Renewable Energy Agency, the Climate Change Authority, the Clean Energy Finance Corporation, even the Department of Climate Change itself – will be dismantled. The war against carbon will even spill over into academia, with reports today that the Coalition would start vetting Australian Research Council grants to make sure they weren't wasted on research on public art and climate change, to take one very specific example.

As Fairfax's Ben Cubby observes today, for all its carbon contortions, Labor eventually teamed with the Greens and independents to put in place a policy framework that had the ability to reduce Australia's carbon emissions. After the wrecking ball of an Abbott government moves through, Cubby writes, “in all likelihood, this policy infrastructure will have to be rebuilt from the ground up in three or six years' time.”

We constantly hear reports of how disengaged voters can't see the difference between the Coalition and Labor. On climate policy, there is a clear difference. The difference is not just over the narrow issue of the carbon tax. It is now about which party will actually reduce emissions. More broadly, it is about whether Australia will play its part in helping to stabilise the climate, or turn up the burners on a cooking planet.