Did Tony Abbott mislead the public on the cost of emissions reductions? A Government report quietly released on Friday afternoon suggests he did, and that his direct action policy is costing us more than it needs to, writes Greg Jericho.

Last Friday afternoon the Government released two reports relevant to climate change. The timing of such releases should always prick one's attention, because it invariably means it involves something the Government would rather everyone ignore. And the Government certainly would like to ignore these reports.

The two reports showed that the Prime Minister has misled the public on the cost of larger cuts to emissions and that the Government's current direct action policy is a high cost alternative. They also showed electricity greenhouse emissions have once again started to rise.

The first of the two releases on Friday came via Environment Minister Greg Hunt with the latest quarterly update of our greenhouse gas emissions.

It shows that since the end of the carbon price, electricity emissions have started rising:

In the March quarter of this year, for the first time since 2012, the greenhouse gas emissions from electricity generation were higher than they were a year previous:

This occurred despite the report also showing that the demand for electricity in that period had actually fallen 0.3 per cent.

In his media release, Greg Hunt made no mention of electricity other than to refer to the "hike" in electricity price due to the "carbon tax". Mr Hunt instead focussed on the overall figure of greenhouse gas emissions - excluding changes in land use - which saw a 0.4 per cent fall in the March quarter.

But given electricity accounts for a third of our greenhouse emissions that's really where the focus of emissions reduction lies. Thus it was apt that on the same day the Government finally, and with no fanfare whatsoever (not even a media release), released the modelling behind the Government's target of emissions cuts for 2030.

The Government's proposed policy is to cut emissions to 26-28 per cent below 2005 levels by 2030. The modelling suggests this would cut our GDP in 2030 by 0.3 per cent compared to what it would be if we just kept to our 2020 target of about 13 per cent below 2005 levels.

When announcing the targets, Tony Abbott told the media that "the modelling that we have done suggests that achieving a 40 per cent reduction by then will be much more expensive. It will be over 2 per cent of GDP".

The modelling, however, shows that statement to be a complete fib.

A 45 per cent cut of emissions by 2030 is estimated only to cut GDP in 2030 by between 0.5 per cent and 0.7 per cent.

But the modelling did not only reveal the Prime Minister was being careless with numbers, it also conclusively showed that the Government's policy of not allowing emissions reductions to be made through the purchase of international permits is significantly worse for Australia's economy.

The modelling shows that were the Government to allow up to 45 per cent of Australia's reduction target to be met through purchase of international permits then rather than a 0.3 per cent hit to GDP in 2030 the hit would be 0.2 per cent.

Similarly employment would be 0.087 per cent below what it would be were we to cease cutting emissions after 2020, but if we did not allow purchase of international permits it would be 0.12 per cent lower.

The modelling shows that with a target cut of 26 per cent, allowing purchase of international permits would reduce the hit to our GDP in 2030 by 25 per cent, and the bigger our target, the more benefit comes from using overseas permits.

This comes into sharp relief when we look at the projected impact of the emissions target on the outputs of Australia's industries.

The modelling suggests that under the Government's proposed target, Australia's coal mining output in 2030 would be 7.6 per cent lower than it would be if we held our emissions steady from 2020 onwards. Were we to cut our emissions by 45 per cent, coal mining output would be 18.7 per cent lower.

But were we to allow international permits to be purchased the hit to the coal industry would be much reduced:

With a target of 26 per cent, the hit to the coal industry output goes from 7.6 per cent to 4.3 per cent. Were the targeted cut of emissions to be 45 per cent below 2005 levels, the output of the coal industry would be expected to be 14.6 per cent below what it otherwise would be. But if international permits were allowed to be purchased it would be just 8.7 per cent lower.

The problem is the Liberal Party's current policy is to not purchase such permits - mostly because that would in effect make Australia part of a de facto emissions trading scheme.

In the Liberal's 2013 election platform it argued that "we will reduce emissions inside Australia, not by paying billions of dollars to foreign carbon traders".

Abbott in 2011 suggested buying carbon permits to meet an emissions reduction target was just a "get-rich-quick scheme for foreign carbon traders".

The same year he told Alan Jones that money spent on carbon permits is "money that shouldn't be going offshore into dodgy carbon farms in Equatorial Guinea and Kazakhstan".

This modelling, however, makes clear that reducing emissions without accessing international permits is the much more expensive way of doing it.

When announcing the Government's target, Abbott and the Foreign Minister, Julie Bishop, were asked by Guardian Australia's Lenore Taylor about the possibility of allowing international permits given the lower cost.

Ms Bishop replied that "we believe that we can meet this target without access to international units". But she pointedly suggested the Government would "look at this again in 2017, 2018, or beyond".

Certainly business groups would be very glad to hear this. But the Prime Minster quickly put cold water on the idea by reiterating his view that there "should be domestic reductions in emissions rather than instantly rushing off to try to get them from other countries".

And while it is admirable that Abbott should believe Australia should reduce our own emissions, the reality is the modelling undertaken by Warwick McKibbon for the Government puts a lie to statements by the Prime Minister on the costs of larger cuts in emissions.

The modelling also shows that the Government's current policy approach of ignoring the international carbon market will hurt Australia's economy.

Greg Jericho writes weekly for The Drum. He tweets at @grogsgamut.