Trust me I know all about Ian Plimer...I used to be a big supporter of his when he took up the debate against creationists. Now...I don't know what to think. I can only assume his close association with mining companies has somehow clouded his mind. There's no way you can call anyone who denies the seriousness of global warming a "skeptic" - scientists are skeptical by nature, and if you read the IPCC report, or realclimate.org you'll see plenty of good examples of skepticism - accepting that there are unknowns, that there is more to work, that some hypotheses regarding potential effects of global warming are, at best, controversial. OTOH, Plimer is a best contrarian, or just plain in denial. He's certainly well out of his depth regarding climate science, at any rate. And let's not even get started on Bob Carter. But whatever...their opinions on the matter are pretty irrelevant.

Wiz, like you, I admire Plimer for his stance in the creationist
debate. He is clearly no fool. So I will reserve judgement until
I read as to what he has to say and what his critics say about
his claims.

As a geologist of some repute, he should actually know quite alot
about this topic, but I'll wait and see. If his arguments are
all wrong, he'll soon be shot down in flames by others.

I happen to live in South West Western Australia, the area claimed
to be the worst in Australia in terms of the effects of climate
change. Certainly in this district, I'm actually having one of
my best seasons ever and climatologists predictions regarding
this season have been very wrong. So we clearly don't quite understand
it all yet.

Main thing is that Al Gore has stirred up enough debate for people
to start seriously looking for answers. Not only that, the Americans
finally realise that the Arabs have them by the proverbial testicles
when it comes to energy, so they have to do something about it.
Those things I feel will lead to positive technology developments
and change.

If the planet does warm by 5 degrees, due to our activities, then
clearly we have not been living sustainably and nature will sort
it all out with a thud. Perhaps only a couple of billion humans
will be left. Hopefully they at least will have learnt through pain,
that sustainability matters. At the present time, a whole lot
simply won't accept that. But then its always been my claim
that people are smart enough to invent new things, not smart
enough to always use them wisely. They also seem to need pain to
learn.

Is carbon trading a 'market mechanism'?

http://www.ozpolitic.com/forum/YaBB.pl?num=1191728697

Freediver, I guess I must be one of those few "lay" economists who would generally prefer to see an emissions tax (offset with reductions in either payroll tax or GST) over a trading scheme. I agree - neither mechanism is really any more or less "market-oriented" than the other. Indeed, even mandating maximum emissions levels and simply charging penalty fees for breaching these levels would arguably lead to much the same result (and there is evidence that mandating pollution levels is actually more effective than trading schemes, when comparing SO2 reductions between Europe and North America).
The only real advantage of trading schemes is that they reward companies that actively sequester existing emissions. But there is a lot of debate as to how well we understand this process (e.g. some forestation may actually increase global warming, because it lowers the Earth's albedo), and how feasible it is to measure emission sequestering. At any rate, you could still have a system where a heavy GHG emitter, say BHP, paid for another company to sequester existing emissions (e.g. by planting tropical rainforests), and was allowed to deduct that from their output before the tax charge was worked out.
The most critical elements of any such scheme is to minimize bureaucracy and red-tape, reduce opportunities for abuse, and to plan for a gradual introduction, over at least a 10 year period.

Yabby, some of Plimer's claims about CO2 emissions (e.g. wrt seismic activity) make me question his expertise as a geologist, not to mention any understanding he may have regarding climatology, or marine ecology (claiming that the Barrier reef will benefit from global warming!). I hate to say it, but it does seem like he's becoming slightly potty in his old age.

It's good to hear someone else on the tax bandwagon. Would you consider contacting your local reps, senate candidates and the major party candidates for treaurer about this? I spoke in person to Bob Brown, Andrew Bartlett and Claire Moore about this on the weekend. They are definitely receptive to the idea, but more of a push is needed. Also, you could consider joining the mailing list for the sustainability party:

http://www.ozpolitic.com/sustainability-party/sustainability-party.html

"The only real advantage of trading schemes is that they reward companies that actively sequester existing emissions.

As you suggest, a tax scheme could also do this, either by a direct subsidy for sequestration, or by an exemption from the tax for offset emissions. Of course, the technical issues remain. I think it would be better to leave the sequestration in government hands, at least until the techniques are proven.

"and to plan for a gradual introduction, over at least a 10 year period

I think that a tax on CO2 emissions from power stations and petrol could be set up almost overnight. Provided the taxes were offset with tax reductions elsewhere, the impact on the economy would be minimal. The tax scheme allows for gradual change by allowing polluters to pay a predictable price until they can make the necessary changes. Maybe you could hike up the tax in ten years if faster change was deemed necessary.