In part, Kevin Rudd says it is because the rest of the world hasn't agreed to any signifcant or binding targets so we won't. Why can't we be a leader in the world? What's wrong with setting the pace? After all, it is only the planet we're trying to save here. And it isn't like we've got another one.
The other reasons is what we're apparently trying to balance climate change control with economic growth. Here's a news flash: if we don't do something significant to save the environment then we won't be having any economic growth at all. We'll probably be signing a death warrant for the human race. Plus, investing in the technology to help reduce emissions will increase economic growth because we'll have to build new technology to get rid of the old stuff that emits so much carbon.
Now, you might think my "death warrant" comment above is a bit harsh but I don't think so. The best case here is that we do something to slow down our emissions and control climate change and the scientist's dire predictions are wrong - humans are not responsible for climate change (as a whole). That isn't such a bad outcome - we've reduced our emissions anyway and made the environment a healthier place for everyone. The worst case is that we don't do enough and the environmental change we've already started spirals out of control and the planet eventually becomes unlivable.
Sure, there are lots of scenarios in between these two but what we should be doing is planning for the worst case. And Australia should be taking a lead in this - after all, why not? We have intelligent people here and I'm sure we can start to make a difference.
Yes, in the scheme of things Australia is a small emitter overall (but a large per-capita emitter). But again, why can't we be the shining example?
The other thing our government is doing wrong is subsidising large carbon emitting industries. Why are we doing this? Anyone with half a brain has known about carbon emissions for at least 30 or 40 years. I've been hearing about it all my life - it was original described as "greenhouse gas emissions". So if you own a business that depends on that and you haven't done anything about it then you should be sacked. You've had more than enough time to think about what to do rather than continuing to run your business the way you have without any thought for the future.
Instead, the government should be subsidising research and development into renewable energy resources; encouraging people to use those resources; and making sure that we export those ideas and technology to other countries.
As always, I could rant for hours. But I won't.
Update: An interesting comment from New Scientist regarding investing in ambitious climate change goals.