You don’t have to be a policy expert to realise that if the Coalition is serious about climate change, it will have to take its Direct Action Plan back to the drawing board.

Having spent time analysing the parties’ climate change policies for the University of Melbourne’s Election Watch, I’m disappointed that yet another speech by Greg Hunt, the shadow minister for climate action, failed to answer key questions about the Coalition’s climate policy. As it stands, the Direct Action Plan falls short as a policy model for climate action: it’s questionable whether it will enable us to control and reduce our emissions at all, let alone to do so in a way that’s cost effective and fair.

The Coalition has said it accepts the climate science and is committed to Australia’s internationally binding target to cut emissions by 5-25% by 2020. The climate science makes it clear that without good policy intervention, the concentration of greenhouse gases in the atmosphere will continue to rise far above safe levels.

The first move of a Coalition government would be to repeal the laws establishing the current carbon price policy and replace them – by the middle of next year at the earliest – with a policy called Direct Action.

Essentially, Direct Action is a scheme that rewards entities that voluntarily reduce their emissions. So, if you're an emitter you can propose an emissions reduction project to the government − it might be to improve your energy efficiency, store carbon in the soil or plant trees. The government compares your proposal to other project proposals, and picks the ones that will be the cheapest to implement. If it picks yours, you enter into an agreement to cut your emissions and are paid once you've delivered the emissions cuts.

You don't have to be a policy expert to see where major cracks could form in this policy model. First and foremost, if the cash reward is to be the driving incentive, how large would the pool of funds need to be to drive the level of emissions reductions necessary to meet our 5-25% target? A report published last week estimates that, depending on the level of Australia’s 2020 target, it would cost $4-15bn more than the Coalition has currently budgeted. In fact, the report claims that the funding the Coalition has pledged is so inadequate that emissions would rise by 8-10% by 2020.

Under Direct Action it is the public, not polluters who pay. Is that fair? Unlike under a carbon price, there’s no cost, no disincentive, to keep polluting at the same rate. Indeed, Hunt recently suggested that the Coalition no longer even intends to penalise polluters that increase their emissions. So, Direct Action (ie taxpayer) funded projects would need to cut enough emissions to offset the emissions of non-participants.

Predicting and controlling the trajectory of Australia’s emissions under Direct Action would be quite a challenge. Without an annual cap on emissions or price per tonne of emissions as is in place under carbon price models, how would a Coalition government ensure that we are on track to meet our international obligations and reduce emissions to safe levels? What happens if projects fail to deliver the cuts as promised? Can we afford a policy that could leave our health, communities and property exposed to the substantial risks posed by climate change?

The Coalition’s policies also jeopardise investment in renewable energy. It has promised to scrap the Clean Energy Finance Corporation, the $10bn body set up to stimulate private investment in renewable and clean energy technologies, and to review the Renewable Energy Target (RET) in 2014. According to the chair of the peak body for the clean energy sector, the uncertainty created by the prospect of a second review of the RET in two years is deterring investment in renewable energy. Coupled with abolition of the carbon price, this uncertainty will make it more expensive to meet the RET.

Some have pointed out that at best Direct Action is a short-term model that is not viable in the long run. Yet the shortcomings of the Direct Action Plan as it stands are striking. If the Coalition is serious about tackling climate change, then it must offer voters a credible alternative to the carbon price. The various iterations of Direct Action the Coalition has presented to us so far simply don’t cut it.