Why are we messing around with carbon credits? Why not just write an Australian Standard for carbon emissions and give an implimentation date (or series of dates)?
Australian standards are great because they can be written when nobody has any idea how they will be met. But as soon as the problem is out there the designer/engineers find a way of conforming. Why not just have an AS giving a sliding scale of permissible emissions per kilowatt of energty produced and let those who have the ability solve the problem get on with it? Politicians, accountants and business leaders don't have a clue on technical matters so give it to those who do. No argueing over taxes or credits. No argueing over who recieves excemptions. No new layer of government to oversee it. Just write the AS and solve the problem.

The capacity of increased atmospheric CO2 to increase temperatures, from whatever the source (natural or anthropogenic), is very limited above 300ppm. From around 300ppm to well over 800ppm the warming effect of atmospheric CO2 declines to about 1ºC or less increase in temperature. Additional atmospheric CO2 makes virtually no difference to temperatures.

To all intents and purposes there is no molecular difference between natural and anthropogenic CO2 in terms of heating behaviour and estimated lifetime in the atmosphere (around 12 years by the way) before reabsorption by oceans, photosynthetic organisms or plant life.

If an emission trading scheme (ETS) is successful in reducing anthropogenic CO2 levels back to a proportion of that emitted in the year 2000 (the yearly level most widely quoted) the effect will be very minor (if, in fact, it makes any difference at all) as this reduction pales into insignificance when compared to natural variations in atmospheric CO2 levels such as those caused by oceanic outgassing (approximately 91 billion tonnes compared to anthropogenic CO2 output of 7.5 billion tons).

In other words a fully implemented globally-applied ETS is likely to reduce atmospheric CO2 by only several parts per million.

Mike Pope, how is this going to make any difference?

It is time you figure out that Rudd is a populist. He likes saying the popular things, Grocery watch and Fuel Watch are prime example, even if they really do nothing. His aim is to do what he can to get re-elected next time (which politician isn't)

He will do what it takes to not cost any Australian job, not give people a reason to kick him out. So it is not the Senate, it is not that he does not care about the environment. It is just very low on his priority list.

He is a politician afterall

Not only is Rudd weak by caving in to vested interests but he has broken a core election promise. Apart from the incentive of nontrivial carbon charges the ETS also created a funding mechanism for a shift to green technology. It seems to me for all his flaws Howard actually took some positive steps like a rapid rate of wind farm building. Not having to appease frequent flier greenies Howard also proposed nuclear baseload, a concept that that doesn't sit well in Rudd's ecotopian vision.

I disagree that Australia is a bit player in the global emissions scene. Emissions from exported coal are higher than domestic. Anecdotal evidence suggests a drop in coking coal exports, offset by Chinese attempts to buy a Rio Tinto subsidiary. The Chinese want to burn 3 bn tonnes of coal a year in which case we should either carbon tax our coal exports or goods imported from China. The absence of an early domestic carbon cap has lead to results like an increase in brown coal burning, boosted I believe by power exports to Tasmania via the Basslink cable. Meanwhile those Barrier Reef corals do it tough and may not adapt.

Re other mitigation suggestions I think technical standards should complement a carbon cap eg every new car to use less than 5L/100km. With feed-in tariffs overseas experience suggests the schemes are unaffordable and have limited success. It is better to increase capital subsidies to solar PV funded by...you guessed it, a tough ETS.

Define a 'meaningful' reduction. More than 1% of global emissions? Not even possible for Australia is it? I suppose we could stop all mining and exporting of any raw materials...

If methane levels accelerate then it is all moot.
Permafrost is releasing methane now due to the warming that has already occurred. If this "tipping point" is actually reached then the GW denialists are right (but for wrong reasons): CO2 mitigation is useless.
It all depends on the data.
Anyone keen on funding an Ark project? :-)