Matthew Wright and Trevor Jack argue that  'a lower carbon price may bring short-term political gain, but credibility on global warming would go up in smoke'.   

Some quotes: An argument for transitioning to the ETS earlier than currently legislated is that it would be cheaper. True, in the short term, given that the carbon tax would be around $25 and the ETS cost would be about quarter of this. But this is cheaper in the same sense that buying a five-litre can of fuel is cheaper than buying a 20-litre can. Each is a can of fuel. But the useful content is different by a factor of four. Similarly, a $25 carbon price buys much more real abatement than $6. And the policy objective is surely real carbon abatement and not just “anything so that we can be perceived to be doing something”? …
The effect on global warming? Carbon pricing can affect short-term production decisions and thereby change short-term CO2 production. A lower carbon price should increase, by a small margin, CO2 emissions. But the main imperative for any carbon abatement policy, is to affect long-term investment decisions and transform the community and economy to a cleaner future. For example, any serious response to global warming must result in no new fossil-fuelled power stations. Decisions on investments with 30-year-plus lifetimes are based on all the future circumstances, including explicit carbon costs. If investors perceive the Australian government taking a token approach to global warming and expect this to continue well into the future, they should factor lower future carbon prices into their decision making – i.e. more coal-fired power stations rather than better/smarter grids, energy conservation measures, renewable power. On the other hand, if investors perceive that the government and community generally want action, they will expect carbon pricing to rise steeply over time. Thus, investors would invest in renewable alternatives, rather than fossil fuels. Combined with the Coalition's policies, which provide no incentive for economy-wide transformation, the effect on global warming of the government implementing a lower carbon price is likely to be further delay in de-carbonising the Australian and global economies.
On political standing? With appropriate spin, (possible) lower costs to consumers, higher profits to generators, and omission of the need to fund the revenue shortfall, there may be short-term political gain, relative to the “ban the carbon tax” alternative, in switching to a lower carbon price. But the government's credibility in terms of having a serious long-term strategy to address global warming would become similar to that of the opposition – essentially non-existent. If the political need is to be seen to be doing something, then an ETS, with a floor around $25, might dissociate Rudd's “new policy” from Gillard's so-called dishonestly introduced carbon tax yet maintain the price at a level at which it is plausible, that investors would believe the government to be serious and thereby consider cleaner rather than more carbon-intensive investments.

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