The commitments included pledges to .... generate 20 per cent of Australia's energy from renewable sources by 2020.

At current rates of population and economic growth (last 5 years' average 3.24%) Australia in 2020 could be using 50% more energy than today. If only 20% comes from renewables as pledged we will still be using 20% more fossil fuels than we are today.

Agreed - these sorts of targets aren't all that helpful (something we've discussed before).

Its better to aim for a percentage reduction of present day emissions - eg reduce emissions by 60% by 2030 or suchlike.

In the real world, I still thinks its better to implement a carbon tax, make the rate increase monotonically over time, give people a tax cut to compensate and put some sort of penalty into WTO trading rules for non-compliers.

The tax and tariff systems already exist and are vigorously enforced, and thus have some hope of making cuts in emissions real by virtue of making them uneconomical.