Jennifer, I sincerely hope you are right. We know with a great deal of certainty that CO2 adds to the greenhouse effect. We do know that CO2 concentrations have risen significantly (by 35%) since the Industrial Revolution when we started to burn substantial amounts of fossil fuels releasing CO2. So there is a high likelyhood that our burning of fossil fuels has increased the CO2 concentration significantly. You probably wouldn't disagree with any of this so far (although many seem to).

What I agree is that we may not know with the same certainty what the impact will be on the environment from the know rises in CO2 concentration. This is where risk analysis is needed.

When we buy an insurance policy we rely on risk analysis experts to assess those risks for us and place a price on the risk of our house burning down for example. We can ignore this advice and not pay for the insurance or we can assess that we cannot afford to lose the house and pay an appropriate insurance premium.

I see the "carbon price" as an insurance premium. The expert risk assessors may have got it wrong. But they may also be right.

The government cannot afford to let the "house" burn down so they wisely (in my opinion) buy an insurance policy to stabilise CO2 concentrations and (hopefully) stop the house fire.

Do you take out house insurance?

I hope the Brisbane rally is an enthusiastic and positive event Jennifer. For those of us unable to attend thanks for your help and may your enthusiasm for a "fair go" remain boundless.

Martin N, candid opinion on neither side seems to share your view that a Carbon Tax will "stabilise CO2 concentrations" so all the best in that dream.

Martin N - yes, all things being equal more CO2 in the atmosphere should mean temperatures will increase, the real question is by how much. The actual physics says that a doubling of carbon concentrations will increase temperatures by one degree centigrade. (Do you want the actual reference? I'm a tired of giving it.) Much of the argument has been about the feedback effect added by the climate models. So can you add to the debate? Do you think the feedback effect is more than one or less than one, and how do you know?

Then we come to your insurance analogy. Will a carbon tax have any noticeable effect on world emissions? No. It is clear that China, America and India are not going to put a price on Carbon, so what do we hope to achieve by a tax? Our insurance premium isn't going to buy us any sort of policy, or buy anything at all except a tiny amount of green cred. And we all know how much that is worth.

I respect anyone who will get out on the streets to deomonstrate for their convictions,Jennifer.

Curm, you a thinking and also paid analyser of the global warming issue. I don't include you with the nest of vipers who mindlessly deny in these pages that there is a problem with global warming and have never written anything constructive in their lives. However I think though that we can analyse global warming to death. As I see it there are four over-arching facts which are hard to argue with:

1. Greenhouse gases are increasing in the atmosphere,are causing increasing global temperatures (I think you have acknowledged this). We are already seeing the predicted increasingly severe weather events (that is droughts floods, tornadoes)as a result.

2. There is another big problem - over-use of the world's scarce mineral resources. Both of these problems will cause problems for coming generations including our chldren and grandchildren.

3. The solution to both is the same - cut down on wasteful consumption of fossil fuels.

4. Australia is per capita the most resources rich nations and also in the top 3 of high greenhouse gas emitters in the world; also among the most affluent of nations. That is why we should be leading, not trailing the world in greenhouse action.

If we agree that we should reduce use of fossil fuels (de-carbonise our economy) there are many ways to do this - voluntary (does anyone really think this alone will work?), C price, feed-in tarriffs etc. But no-one has yet shown how it can be done without including a carbon tax as a central plank of action. I think the analysis should go into how this can be done.

Once a forest, savannah or any form of original vegetation reaches a mature state due to the limit of the amount of vegetation sustainable by available water and nutrients resulting from the degradation of non organic minerals, the carbon cycle is such that there is no net gain by way of a reduction in atmospheric carbon dioxide levels. The exception is the carboniferous materials which are eventually converted and laid down as coal or oil deposits.

Interestingly, to the chagrin of our dedicated environmentalists, when a forest is harvested, the carboniferous materials such as timber are then locked away for perhaps a century or more and the regrowing forest then positively contributes to carbon dioxide abatement.

The climate change enthusiasts have also got something else very much wrong. The warming of the oceans, which is undisputed, will result in the evaporation of greatly increased amounts of water which will fall as rain. The drought breaking rains of the last 12 months are the result of ocean temperatures. None of this increased rainfall was predicted by the CSIRO or the various meteorological organisations in Australia yet for some improbable reason, the cutbacks in Murray Darling water allocations were based on a 10% reduction in river flows. The consistent drought in South Western WA is because that area derives its winter rainfall from the Antarctic Current. This as yet, has not increased in temperature as its heat source is the great ocean currents which transfer heat from the tropics to the Arctic and Antarctic waters.

As an example of what will happen with increased rainfall, the Simpson desert is green for the first time in many years. The Australia wide increase in vegetation will result in the fixing of huge amounts of carbon, concievably far more than all our puny abatement measures.

Roses1 - well, thanks, I guess.. sure we can cut down on wasteful fossil fuel use. The real question has always been how far are we prepared to go, particularly considering that Australian efforts will simply have no effect on the supposed problem?

Think of it as a pay cut. How much of a pay cut.... or perhaps a fairer approach is, how much of future pay increases are you willing to forgo, in the name of emission reductions? No, it doesn't work out that you can have a cleaner economy that generates more. We will have to pay to forgo emissions and that is the end of that. How much do you think voters will want to pay, particularly as no one has been able to show that cuts in Australia will have any effect.

That's the dimension of the problem.

As for the business about humans contributing to CO2 in the atmosphere, your point one, I would like to take issue but I will have to bide my time. Having had the doubtful honour of looking through some of the material on the carbon cycle theory (the time CO2 hangs around in the atmosphere), I very strongly suspect the whole thing is a concoction. But then you would rightly point out that highly qualified people think otherwise, and that I haven't got anything definite to point in the other direction.

So there you go, you've got me on that one.